The Structural Engineer 2020-10

 

October 2020  Volume  Volum e 98 | Issue 10

Setting the standard Could a carbon rating scheme offer a route to netn et-zero zero emissions?

Loadbearing stone buildings

Box-girder Box -girder failures: failures : 50 years on

Unauthorised changes on site

 

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34 Upfront 5  Editorial 6  News

Climate emergency  8  Setting carbon targets: an

introduction to the proposed SCORS rating scheme 14  What do we mean by effi ciency?  A holi holisti stic c appr approac oach h to to redu reducin cing g embodied carbon 18  Rationalisation versus versus optimisation optimisation – getting the balance right in changing times

Professional guidance 22  Business Practice Note No. 35:

Dealing with unauthorised changes on site 24  An introduction to the COBie standard

28 24

Technical 28   Stone as a structural material.    S    T    C    E    T    I    H    C    R    A    R    E    T    R    A    C    K    C    A    J    ©    S    U    P    M    A    C    E    L    T    O    O    B    R    E    D    N    A    T    N    A    S   :    R    E    V    O    C  

37

Part 4: Contemporary loadbearing stone buildings

   0    2    0    2 34   Profile: Sinéad Conneely and   r Laura Hannigan   e    b 37  Viewpoint: The box-girder failures failures 50   o    t years on – lest we forget   c    O 40   Viewpoint: Structural engineering – a

Opinion

    │

14

view from Jamaica

   0 42  Book review: Durability of reinforced    1   e concrete structures   u   s 43   Verulam   s    I

    │ At

the back

   8 46   Diary dates    9

  e   m   u    l   o    V 50 TheStructuralEngineer Jobs 47  Spotlight on Structures 48   Products & Services 49  Services Directory

DESIGN

GLOBAL

BRIEF

OPTIMISATION  

2

3 thestructuralengineer.org | October 2020

  DESIGN

 

LOCAL OPTIMISATION

4

 

 

®

 

Editorial

Upfront

 

PRESIDENT Don McQuillan BSc(Eng), CEng, FIStructE, FICE, FIAE, FIEI, FCIHT, FConsE, MAPM, MAE CHIEF EXECUTIVE Martin Powell EDITORIAL HEAD OF PUBLISHING Lee Baldwin MANAGING EDITOR Robin Jones t: +44 (0) 20 7201 9822 e: robin.jones@istr [email protected] ucte.org EDITORIAL ASSISTANT Ian Farmer t: +44 (0) 20 7201 9121 e: [email protected] [email protected] rg

Robin Jones Managing Editor 

 ADVERTISING  ADVERTISIN G DISPLAY SALES t: +44 (0) 20 7880 7632 e: [email protected]  RECRUITMENT SALES t: +44 (0) 20 7880 6235 e: [email protected] [email protected]  k 

Time to set

DESIGN SENIOR DESIGNER Nicholas Daley  PRODUCTION PRODUCTION DIRECTOR Jane Easterman EDITORIAL ADVISORY GROUP Will Arnold MIStructE Premma Makanji MIStructE  Allan Mann FIStructE Chris O’Regan FIStructE  Angus Palmer Palmer MIStructE Simon Pitchers FIStructE Eleana Savvidi MIStructE Price (2021 subscriptio subscription) n) Institutional: £465.00 Personal (print only): £110 (until 6 Dec) Personal (online only): £110 (until 6 Dec) Personal (Student Member): £40 Single copies: £25 (incl. p&p) Printed by  Warners Midlands plc The Maltings, Manor Lane Bourne, Lincolnshire PE10 9PH United Kingdom © The Institution of Structural Engineers. The Structural Engineer (ISSN 1466-5123) is published by IStructE Ltd, a wholly owned subsidiary of The Institution of Structural Engineers. It is available both in print and online. Contributions published in The Structural Engineer  are Engineer   are published on the understanding that the author/s is/are solely responsible for the statements made, for the opinions expressed and/or for the accuracy of the contents. Publication does not imply that any statement or opinion expressed by the author/s reflects the views of the Institution of Structural Engineers’ Board; Council; committees; members or employees. No liability is accepted by such persons or by the Institution for any loss or damage, whether caused through reliance on any statement, opinion or omission (textual or otherwise) in The Structural Engineer , or otherwise. The Institution of Structural Engineers International HQ 47–58 Bastwick Street London EC1V 3PS United Kingdom t: +44 (0)20 7235 4535 e: [email protected] The Institution of Structural Engineers Incorporated by Royal Charter  Charity Registered in England and Wales number 233392 and in Scotland number SC038263

carbon targets

I HOPE you’re HOPE you’re continuing to find the ‘Climate emergency’ section of The Structural Engineer  useful.  useful.  This month, month, the section focuse focuses s on the the efficiency efficiency of designs and the need to go beyond counting embodied carbon and adopt targets for its reduction.  The first first article builds on the Institution’s recently published guide , How to to calculate embodied carbon, carbon, by considering the question of what a ‘good’ carbon footprint might be (page 8). 8). The authors propose a rating scheme that will allow projects to be graded

of the Merrison Report into the disasters are still applicable today (page 37). 37). Then, as the UK marks Black History Month, Alfrico Adams, a veteran of the Jamaican structural engineering profession, recalls his student days in London and recounts his generation’s efforts to put the profession on a firmer footing in the Caribbean (page Caribbean (page 40). 40). We also conclude our miniseries on stone as a structural material with an article in which authors from Webb Yates discuss their work on a building system aiming to offer a low-

once their embodied carbon has been calculated. With a rating scheme, engineers – and their clients – can then set realistic targets for their projects, and gradually work towards better-rated designs in future.  This is followed by two articles articles with a focus focus on on lean design. First, Ben Gholam of Price & Myers describes a parametric benchmarking tool the practice has developed to allow rapid comparison of the embodied carbon in scheme designs (page 14).. Ian Poole of Mott MacDonald then looks at the 14) relationship between optimisation and rationalisation of designs, and urges engineers to use modern tools to prioritise optimisation and higher utilisation ratios (page 18). 18). Don’t forget that the Institution’s Climate Emergency Task Group is seeking feedback from

carbon alternative to steel and concrete-framed structures (page 28); 28); speak to Sinéad Conneely and Laura Hannigan about their motivations for setting up a small practice and ambitions to produce more carbon-efficient designs (page 34); 34); explore how to deal with unauthorised changes on site (page 22); 22); and present an introduction to the COBie standard (page standard  (page 24). 24). I hope you enjoy the issue.

WITH A RA RATING TING SCHEME, ENGINEERS CAN SET REALISTIC TARGETS FOR THEIR PROJECTS

members on the content being prepared, so please take its climate survey – see page 6 for 6 for details. Elsewhere in the issue, two articles touch on the history of structural engineering. First, Ian Firth looks back on the 50th anniversary of the box-girder bridge failures of 1970, and explains why the lessons 5 thestructuralengineer.org | October 2020

 

Upfront

News

Institution news Instituti

Ele Election of Vice-Presidents 2021–22 2 0 Close of voting: noon on 3 September 2020

 The e re  resu results su t of the election election of VicePresidents Presi Pre si ents of the Institution of Structural Engineers Engine Eng ineers ers for 2021–22 are as follows:

RESULT

2 to elect

DE HOOG, Tanya ROBINSON, Toby

1707

ELECTED

1531

ELECTED

STAVES, John

944

MEHR ME HRKA KARR-AS ASL, L, Sh Shap apou ourr

873 87 3

LAM, Dennis

783

Number of eligible voters:

21,982

 

Votes cast by post:

101

 

Votes cast online:

3293

Total number of votes cast:

3394

Turnout:

15.4%

Number of votes found to be invalid:

Institution news

Don’t forget to take the climate emergency guidance survey  In late 2019, the Institution set up a Climate Emergency Task Group, with the goal of driving its response to the climate emergency. One of the remits of the CETG was to publish guidance, and during the last six months the group has organised guidance notes, viewpoints and worked examples across many topics related to the climate emergency.

Total number of valid votes to be counted:

0 3394

Civica Election Services can confirm that, as far as reasonably practicable, every person whose name appeared on the electoral roll supplied to us for the purpose of the election: | was sent the details of the election and | if they chose to participate in the election, had their vote fairly and accurately recorded.  All voting material material will be be stored for for six months. months.

Industry news

Institution Fellows recognised by Royal Academy of Engineering  Two leading structural engineers  Two engineers have been appointed Fellows of the Royal Academy of Engineering.

Leroy is also Editor-in-Ch Editor-in-Chief ief of the Institution’s research journal, Structures. Professor Naeem Hussain is

including Stonecutter’s Bridge in Hong Kong and for the client design for the Queensferry Crossing in Scotland.

 The CETG is now now seeking seeking your help to set the direction for future guidance. The group would like to know what guidance you would find most useful to help you combat the climate emergency in your work.  There  Ther e are are two two surveys surveys – one one to determine regional needs, the other to look at overall requirements across the whole membership. Please complete either survey (or both!) and ask your colleagues to do the same – the more feedback the group receives, the more help it can provide to members. Note that both surveys are anonymous.

Leroy Gardner, Professor of Structural Engineering at Imperial College London, is highly regarded internationally for his research in structural steelwork and contributions to standardisation and teaching of structural engineering. His research has underpinned design code developments in Europe, the USA and the Far East. He is the UK’s representative on several international standardisation committees, a natural consequence of his significant national contributions.  As Director of Undergraduate Undergraduate Studies, he transformed his

a Director, Fellow and Global Bridge Design Leader at Arup. He is one of the world’s leading bridge engineers and has been personally responsible for the leadership of the design of many major bridges worldwide,

Naeem has contributed to the development of bridge technology and is the recipient of many awards, including the RAEng Prince Philip Medal in 2012 for Exceptional Contribution to Engineering.

Take the surveys at www. istructe.org/resources/  news/climate-emergencyguidance-survey-2020/ .. guidance-survey-2020/ 

department’s student satisfaction department’s score from bottom of Faculty to top in College. His promotion to Professor at the age of 36 was the youngest ever in Civil Engineering at Imperial College.

éProfessor Leroy Gardner

éProfessor Naheem Hussain

6 October 2020 | thestructuralengineer.org

News   Upfront News

 

Industry news

Concrete sector targets carbonneutral future Forty of the world’ world’s s leading cement and concrete companies have unveiled a joint industry ‘2050 Climate  Ambition’. The ambition statement statement demonstrates the commitment of the industry across the globe to drive down the CO2 footprint of the product, with an aspiration to deliver society with carbon-neutral concrete by 2050. Launched by the Global Cement and Concrete  Association on behalf of its member member companies, the ambition statement represents a critical milestone for the industry. It is the first time it has come together globally to state a collective ambition for a carbon neutral future.  The statement identi identifies the essential levers that will be required to achieve carbon-neutral concrete, including: reducing and eliminating energy-related emissions, reducing process emissions through new technologies and deployment of carbon capture, more effi cient use of concrete, reuse and recycling of concrete and buildings, and harnessing concrete’s concrete’s ability to absorb and store carbon from the atmosphere.

Industry news

Mayor of London and Bryden Wood launch new version of housing design app Supported by the Mayor of London, tech-led design practice Bryden Wood and leading residential consultancy Cast have released a new version of the cutting-edge PRiSM app, which harnesses the latest digital technology and data to help design and build manufactured homes.  The pion pioneer eering ing app is the the latest development in London’s homebuilding strategy and the next step towards the technology and training that City Hall’s Covid-19 Housing Delivery Taskforce called for in July. London is the first city in the world to make a freely available app of this kind, at a city-wide level, sharing expertise and using technology to transform the design process and get the city building the homes Londoners need.  The goa goall of this ope open n sourc source, e, free free-to-use app is to encourage uptake

surrounding area. These include: | building and neighbourhoods in greater detail |  local amenities | ecology (location and species of trees) and weather patterns | road information, transport infrastructure and site accessibility | land classifications

of modern methods of construction systems across the industry and to show that this type of housing is suitable for many sites across London. Brand new features and extensive upgrades to the technology mean users will experience a rich 3D environment in which to design their housing scheme and can explore numerous new data sets about the

approach to bespoke design with manufacturing-led effi ciency. In addition, PRiSM 2.0 now off ers ers a larger pattern book of housing types and, within these, much greater design flexibility.

Greater understanding of sites’ constraints and restrictions will mean better planning for construction and improved intelligence about which manufacturing process might suit councils’, housing associations’ or developers’ requirements. The PRiSM app is the first step towards a digital planning approach.  The sco scope pe of of PRiSM PRiSM 2.0 has also now been expanded to include a much larger number of design and construction systems, including Bryden Wood’s ‘Platforms’

Find out more about the Climate Ambition 2050 at  https://gccass at https://gccassociation.or ociation.org/climate-amb g/climate-ambition/  ition/ .

Industry news

Sign up to Construction Declares virtual multidisciplinary meetings Construction Declares, in conjunction with Architects Declare, invites you to a series of multidisciplinary meetings around the UK. The meetings will be held on Zoom, and are open to all built environment professionals.  All meetings will include an introduction introduction by a member member of the UK Architects Declare steering group and a discussion led by regional Construction Declares volunteers.  The meetings will run from from 13 October–15 December December 2020, at 17:00 (UK time) on each date. Find your nearest event and register to attend at  at   https://architectsdeclare.com/events .

For out more at https://prism-app.io/ .

Industry news

Draft Eurocodes issued for public comment BSI has issued drafts of two revised iterations of the Eurocodes for public comment. Drafts of BS EN 1990 Eurocode - Basis of structural and geotechnical design and design and BS EN 1993-1-1 Eurocode 3 - Design of steel s teel structures. structures. - Part 1-1: General rules and  rules for buildin buildings gs are available to view at  at  https://standardsdevelopment.bsigroup.  under the ‘Construction’ section of the BSI Standards com/categories/91.010.30 under com/categories/91.010.30 Development portal. Members wishing to review and comment on the drafts should register on the BSI portal and submit their comments by the deadline of 26 October. October.

7 thestructuralengineer.org thestructuralengineer .org | October 2020

   

Planning application Setting procedur procedures carbon targets es Opinion Climate emergency

 

2.Low carbon

Setting carbon targets: an introduction to the proposed SCORS rating scheme Will Arnold, Arnold, Mike Cook, Duncan Cox, Cox, Orlando Gibbons and Gibbons and John Orr present SCORS – a proposed carbon rating scheme for structures – and encourage engineers to adopt carbon targets for their projects.  The Instit Institutio ution n has rece recently ntly published ished a guide on How to calculate embodied carbon1. The guide (free in PDF format) enables a structural engineer to estimate how much embodied carbon is present in their design, at any stage in the design process. For many, the publication of this method has raised the question of what a ‘good’ figure for that carbon footprint might be. In this article, the authors propose the use of a Structural Carbon Rating Scheme (SCORS) that has been informed by project carbon data, and that can be used to compare high-carbon and low-carbon design decisions and options. We compare SCORS to targets set by the Royal Institute of British Architects (RIBA), the London Energy Transformation Transformation Initiative (LETI), and the Intergovernmental Panel on Climate Change (IPCC), and discuss how the reader might set their own targets.  The artic article le highligh highlights ts the the need need to adop adoptt (and hold ourselves to) low targets that are periodically updated and that tend towards

GET T THE GUIDE  How to calculate calcul cal culate ate embodied embodi emb odied ed carbon on is is free free to download ownloa own loa at

www.istructe.org/resources/  .istructe.org/resources/  guidance/how-to-calculateance how-t how-to-cal o-calcula culateteembodied-carbon/  odied-carbon/ .  A har hard rd d copy copy version versio ver sion n is is also is also also available ilable to buy.

zero, starting immediately.

SCORS Figure 1 shows 1 shows the SCORS rating ‘sticker’ suggested for use by structural engineers in communicating the implications of design decisions to those we work with and for.  The SCOR SCORS S rating rating of of an option, on, asset asset,, or company’s portfolio of work is based on the estimated A1–A5 emissions of the primary structure (superstructure plus substructure), calculated in accordance with How to calculate embodied carbon, which outlines calculation inclusions and exclusions, such as excluding the benefits of sequestration or off setti setting. ng. (See Figur Figure e 1.1 of the guide for an explanation of lifecycle modules.) For early-stage calculations, embodied carbon factors should be based on typical values for the country in which the project will be built (including assumptions around

SCAN QR CODE

cement replacement, steel recycled content, etc.), as provided in How to calculate embodied carbon. Once the supply chain is better understood, ‘real’ values based on product-specific environmental product declarations (EPDs) could be used instead.  The A1–A5 carbo carbon n footpr footprint int is then then divided by the gross internal area (GIA) of the completed building (for refurbishment projects the full GIA is taken).  A final carbon count should be uploaded to the RICS Building Carbon Database2 to drive progress around industry

profession – perhaps including a link to these calculations on the final ‘sticker’.

understanding of carbon. The engineer may also choose to make their carbon calculations freely available to all to maintain transparency across the

understand whether their design is high or low in embodied carbon compared with the typical range of industry practice. In SCORS, no diff erentiation erentiation is made between structural type, number of storeys, client brief, presence of a basement, or whether the project is a new-build or refurbishment. Across all building structures, anywhere on the planet and in any configuration, an A rating means that the estimated A1–A5 carbon footprint of the primary superstructure plus substructure substructure is in the range of 100–150kgCO2e/m2 GIA.  As well as allowing allowing comparisons sons between diff erent erent options of the same scheme or to a benchmark, it will allow structural engineers and our collaborators

Using the scheme It is proposed that structural engineers use SCORS to communicate the implications of design decisions. The bene fit of using SCORS is that people assign a meaning to a green A+ rating, or a red F rating, facilitating conversations around embodied carbon with those who hold the most influence. It contextualises the carbon impact of a design, helping engineers, architects, clients and planners

to understand the relative embodied carbon impacts of di ff erent erent types of buildings (e.g. comparing a 30-storey tower with three 10-storey buildings), with the intent of challenging the brief

1: Proposed Structural Carbon Rating Scheme (SCORS) sticker  ìFIGURE

8 October 2020 | thestructuralengineer.org

 

Setting carbon targets  targets  Climate emergency 

TABLE 1: Targets in RIBA 2030 Climate Challenge 4 RIBA targets, modules A–C (excl. B6–7), whole building

 A1–A5 a s % of A–C 6

 Assumed s tructur al car bon as % of whole-building carbon

 A1–A5 s tructures 2030 target (and SCORS rating)

2020 target

2030 target

Domestic

600

300

74%

65%

144 (A)

Non-domestic

800

500

52%

60%

156 (B)

NB All figures are given in kgCO2e/m2 GIA 

TABLE 2: Targets in LETI Embodied Carbon Primer (ECP)5 LETI targets, modules  A1–A5, whole building bu ilding

Structural carbon as % of whole-building carbon (per LETI ECP)

 A1–A5 st ructures 2030 target (and SCORS rating)

2020 target

2030 target

Residential

500

300

67%

201 (C)

Commercial

600

350

65%

228 (C)

Education

600

350

48%

168 (B)

on emissions that will have the most impact today.  

Benchmarking SCORS against existing projects

NB All figures are given in kgCO2e/m2 GIA 

more often. Note that SCORS focuses on A1–A5 (cradle–completion) (cradle–completio n) emissions rather than  A–C (lifec (lifecycle) ycle) emiss emissions, ions, the minimu minimum m scope of a structural embodied carbon assessment according to How to calculate embodied carbon. This is because these are the emissions that we have the most

certainty and control over, over, as well as those which will certainly be released before our deadline to reach net zero of 2050. Whole-building carbon reductions over the lifecycle remain the overall goal, with best practice being to consider A–C emissions, but reporting A1–A5 emissions enables the structural community to focus

2: Data from êFIGURE 2: Data three firms compared for carbon footprint of their designs

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 The range range and grad gradation ation of SCORS SCORS is informed by a review of embodied carbon estimates from 326 projects shared by  Arup,, Price  Arup ce & Myers and Thorn Thornton ton  Tomas  T omasetti. etti.  The data data is a mixed set – sligh slightly tly varying ng calculation methods, different (though appropriate) appropriat e) carbon factors, and a mixture of building typologies and locations. Data also had to be adjusted to cover lifecycle modules A1–A5, with 15% added to account for modules A4 and A5 where only A1–A3 had been investigated. We recognise that there are limitations to interrogating such a small cross-section of the building industry, and welcome any data that firms would like to share to add to this study – please get in touch at [email protected] if [email protected]  if you would like to contribute! Despite the diversity of the calculations, the data allowed us to understand what a typical range of structural embodied carbon impacts looks like (Figure 2). 2). The average score was a high E, and a substantial number of projects were assigned a G due to the inclusion of many high-rise projects in the dataset. The highest reported figure was over 1000kgCO2e/m2. Note that similar findings were shown in the Carbon Leadership Forum’s (CLF) embodied carbon benchmark study3.  

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What does ‘good’ look like? Current UK industry targets  The next next step was to work work out what SCORS rating we should be targeting, now and in the future. In the UK, both RIBA 4  and LETI5 have recently outlined targets for embodied carbon. Both set multidisciplinary whole-building targets (structure, facade, MEP and fit-out) – with RIBA looking at whole-life emissions (A–C,

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9 thestructuralengineer.org | October 2020

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excluding B6–7) and LETI only A1–A5.  Their targ targets ets are show shown n in Tables 1 and 2, 2, and we have calculated the structures-only A1–A5 target and SCORS rating to go with it. It should be noted that

   

Opinion Climate emergency Planning application Setting procedur procedures carbon targets es

(construction) emissions coming roughly two years later – and that typical designs must achieve an A rating by the year 2030.  There  Ther e are, are, of of course, course, other curve curves s that that start at a diff erent erent SCORS rating, or are based on diff erent erent amounts of new floor area, but the curve always requires a dramatic reduction in emissions in the short term, and always ends at net zero by the time we get to the year 2050.  

Setting targets ìFIGURE

3:

Calculation of embodied carbon budget for building structures to 2050

4: Spending the global carbon budget – carbon targets if you start at 350kgCO2e/m2 and reduce emissions by 10% each year  îFIGURE

these are the first formal attempt by the UK building industry to set carbon targets and may be revised further as counting carbon becomes more commonplace and the achievability of targets better understood.  The RIBA and LETI LETI targ targets ets would requ require ire building structures to achieve SCORS ratings between A and C by the year 2030.   Global science-based targets Going beyond the UK, we then wanted to determine what embodied carbon figures our industry will need to achieve in order to limit global warming. The IPCC Global Warming of 1.5°C report 1.5°C report7 estimated that, as of the end of 2017, the atmosphere could absorb a further 580 gigatons of carbon (GtCO2e) to maintain a 50% probability of limiting warming to 1.5ºC above pre-industrial levels*. In the three years since 2017, the remaining capacity to absorb further CO2 is estimated to have reduced to 464GtCO2e8. Figure 3 shows that in order to stay within 1.5°C of warming, we must limit building structures carbon emissions to 21GtCO2e across the world (a rough sum,

but indicating the order of magnitude). Once this 21Gt carbon budget is used up, we must operate at net zero going forwards. So what does this look like year on year between now and 2050? Figure 4 shows 4 shows one such pathway†, based on the 2017 Global Status Report estimate9 of 5.3bn m2 new construction each year. This example curve starts with an E rating (the average rating from our review of structural embodied carbon data) and then reduces by around 10% per year, tapering towards zero emissions by 2050.  The grey dashe dashed d lines nes indicate ndicate the the range range within which diff erent erent parts of our industry might operate, with some achieving lower emissions, others higher. The curve shows ‘design emissions’ – with real

TYPICAL DESIGNS MUST ACHIEVE AN  A RATING RATING BY THE THE  YEAR 2030

Setting your own targets We know that setting the best targets doesn’t come at the expense of client or employee demands. Clients are attracted to sustainable design, policy-makers are starting to demand it, and graduates want to work for firms that prioritise it. The ‘better than average’ engineer attracts the best work – in a market with an increasing focus on sustainability, why would you not want to be outperforming on carbon terms? But until formal targets are adopted (e.g. by institutions or by legislation), individuals and firms must set their own targets if we are to see progress in this area. The authors advocate that all firms should set in-house science-based10 SCORS targets for average structural A1–A5 emissions across all projects (taking advantage of refurbishment projects), projects), and then target year-on-year year-on-y ear reductions. This would form part of a company’s compliance with their Structural Engineers’ Declaration11, notably item seven: whole-life carbon modelling and reduction as part of the basic scope of work. Best practice on individual projects is

* Note that Architecture 2030 in the USA uses the IPCC’s more stringent ‘67% probability’ carbon budget, which is around 40% lower. This would give a global buildings structural carbon budget of nearer 13GtCO 2e.  Architecture  Architec ture 2030 also advo advocate cates s target targeting ing net net zero zero by the the year year 2040 rathe ratherr than than 2050. 2050.   †  The calc calculati ulation on on on which which Fig. 4 is base based d is very simp simplisti listic, c, a more acc accurat urate e model model need needs s to be devel developed. oped. There There are many variations ations that that need need to be be accoun accounted ted for for,, includ including ing di diff erent erent rates of decarbonisation between industries (the construction industry is expected to never quite reach zero emissions, being balanced by other carbon-negative industries) as well as diff erent erent rates of floor area growth (5.3bn m2 per year is a simplistic global average between now and 2060, whereas the figure increases throughout time, and is not evenly spread between continents).

10 October 2020 | thestructuralengineer.org

Setting carbon targets  targets  Climate emergency 

 

UNTIL FORMAL TARGETS ARE  ADOPTED, INDIVIDUALS AND FIRMS MUST SET THEIR OWN then to agree a target with the client and architect at an early stage, in order to ‘lock in’ that target. This could be done in conjunction with an industry-recog industry-recognised nised carbon management standard, such as PAS 2080:201612, and should form part of a wider project strategy such as net-zero operational carbon. Having set targets, firms should also be open and honest with their employees and competitors about how they’re doing. To say ‘we targeted a B rating this year but only achieved a C’ may not sound positive, but it gets people talking, and prompts us to do better next year! We also know that there will always be certain projects where we won’t hit our targets (due to location, type of project, construction demands, etc.), so when setting a company-wide SCORS target, we need to aim higher than the ‘acceptable’ outcome that we ultimately expect to achieve. Perhaps we all need to aim for the ‘40% better’ grey line in Fig. 4. 4.   Roadmap to net zero  This artic article le set set out out to pro promote mote the advantages of using a consistent carbon rating system such as SCORS, and to compare that against various targets set by industry and science. Fig. 4 suggests 4 suggests that we will be targeting A ratings on all projects within 10 years, and we know that an A

   P    U    R    A    /    X    O    B    D  

   G    N    I    S    U    O    H    A    I    V    A    T    C    O    /    S    D    R    A    W    D    E    S    A    M    O    H    T    D    R    A    L    L    O    P  

rating is achievable with the right brief – early engineer involvement, maximised reuse potential, not too tall, well-configured layouts, decent structural floor zones (Figure 5). 5).  A low-car low-carbon bon futur future e can also be sustained by these projects if we consider future reuse, reassembly, reassembly, and ease of maintenance in our designs. However, there will still be much work to do once an A rating becomes the norm, and it is an uncomfortable truth that there are parts of Fig. 4 that 4 that we don’t currently know how to get to.  At prese present, nt, targe targeting ting A++ only only seems seems realistic through low-impact reuse of existing structures, highlighting the need to prioritise reuse in countries where existing assets are plentiful. But how do we do this where this is no such building stock? How will we average an A++ rating for a new-build designed in the year 2040? How will we average figures even lower than that as we

   S    T    C    E    T    I    H    C    R    A    R    E    T    R    A    C    K    C    A    J  

5: 1 Triton Square (Arup, top), Olive Road (Price & Myers, middle), and Santander Bootle Campus (Thornton Tomasetti, Toma setti, bottom) all achieve A ratings or better  ìFIGURE

11 thestructuralengineer.org | October 2020

   

Opinion Climate emergency Planning application Setting procedur procedures carbon targets es

get closer to 2050? How will we ever achieve zero without the use of off setting setting or sequestration? Clearly, there are opportunities ahead for researchers and materials specialists to revolutionise this industry (a topic that the Institution’s Climate Emergency Task Group (CETG) will be reporting on next) but we shouldn’t let that distract us from the immediate need to make a dramatic impact of our own in the here and now.  

Conclusions  This art article icle has sho shown wn tha thatt a rating ng sys system tem like SCORS can contextualise both the carbon impact of our work and the progress that must be made in the coming decade. We are calling on industry bodies to adopt both this, and sciencebased targets, to better scrutinise the structural embodied carbon in our projects, and to accelerate progress in tracking and reducing carbon within the building industry industr y. We acknowledge that SCORS considers the structure in isolation from the rest of the building, whereas the bigger picture involves minimising the embodied carbon of the whole building. However, in order to do this, each discipline must understand its own carbon impact within that big picture, and this is what SCORS off ers ers for structural engineers – a method of evaluating the impact of our piece of the puzzle.  Targ  T argets ets out outline lined d by by RIBA RIBA and LET LETI, I, along with those shown here by setting our own science-based targets, all highlight that there is significant work to do over the next decade to start to control our carbon emissions. Discovering at concept stage that a project is achieving a G rating needs to lead to the question: ‘How do we do better?’

Firms need to make tracking carbon a standard part of their services – something that asset managers13,14 and policy will soon demand of us anyway (e.g. the Greater London Authority15 intends to make this a planning regulation soon). They should then share the results of their calculations using the RICS Building Carbon Database2 so that our industry can better understand their impact and trajectory traje ctory..

  Will Arnold MEng, CEng, MIStructE

2030 is not very far away, and if we are to achieve ratings of A and better, we need a greater prioritisation of reuse in addition to everything we already know about lean and effi cient design. We must not do any of this without considering the whole-life carbon impacts of our projects, but the certainty and imminence of today’s carbon emissions must be considered in the context of a rapidly depleting carbon budget.

Mike Cook is a Partner at Buro Happold and Chair of the Institution of Structural Engineers Climate Emergency Task Group.

Will Arnold is a Senior Structural Engineer at Arup and the Institution of Structural Engineers.

 

Mike Cook  MA, PhD, CEng, FREng, FIStructE

 

Duncan Cox BA (Hons) Duncan Cox is a Senior Associate at  Thornton Tomaset  Thornton Tomasetti ti where where he focus focuses es on integrating sustainability into their facade and structural designs.

 Ackn  Ac know owle ledge dgeme ments nts  Thank you you to Laura Laura Batty (Heyne Tillett llett Steel), Ed Clark (Arup/CETG), Ben Gholam (Price & Myers), Dr Jannik Giesekam (University of Leeds), Mike Gryniuk (Structural Engineering Institute/SE2050), Will Hawkins (University of Bath), Monica Huang (CLF/University of Washington), Premma Makanji (Price & Myers), Laura Rasmussen (Architecture 2030), Mike Sefton (CETG), Kate Simonen (CLF/University of Washington) and  Alex Tait Tait (RIBA) (RIBA) for their review review of this article and their fantastic suggestions about how to make it more useful.  Thank you you also to members members of Arup’ Arup’s s Structural Engineering Sustainability Hub (SESH-UK) for their valuable input into some of the main ideas around this article.

 

Orlando Gibbons MEng Orlando Gibbons is a Structural Engineer at Arup and member of the Institution of Structural Engineers Sustainability Panel.

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John Orr MEng, PhD, CEng, MIStructE, FHEA  [email protected]

@IStructE #TheStructuralEngineer

Dr John Orr is University Lecturer in Concrete Structures and EPSRC Early Career Fellow at the University of Cambridge. His teaching and research are closely linked to sustainable construction, and improving construction sector productivity.

REFERENCES 1) Gibbons O.P. and Orr J.J. (2020) How to calc calculat ulate e

embodied carbon [Online] Available at: www.istructe.

org/resources/guidance/how-to-calculate-embodiedcarbon/ (Accessed: September 2020) 2) Royal Institution of Chartered Surveyors (2020) 

RICS Building Carbon Database [Online] Available at:

www.rics.org/uk/products/data-products/insights/ricsbuilding-carbon-database/ (Accessed: September 2020) 3) Carbon Leadership Forum (2020) Embodied Carbon Benchmark – Data Visualization [Online] Available at:

http://carbonleadershipforum.org/projects/embodiedcarbon-benchmark-study-data-visualization/ (Accessed: September 2020) 4) RIBA (2019) RIBA 2030 Climate Challenge [Online]  Availab  Ava ilable le at: www www.ar .archi chitec tectur ture.c e.com/ om/-/me -/media dia/  / files/ 

Climate-action/RIBA-2030-Climate-Challenge.pdf (Accessed: September 2020) 5) London Energy Transformation Initiative (2020)  LETI Embodied Carbon Primer [Online] Available at: www.leti.

london/ecp (Accessed: September 2020)

6) RICS (2017) Whole life carbon assessment for the  built envi  built environ ronmen mentt (1st ed.) [Online] Available at: www.

rics.org/globalassets/rics-website/media/news/wholelife-carbon-assessment-for-the--built-environmentnovember-2017.pdf (Accessed: September 2020) 7) Intergovernmental Panel on Climate Change (2019) Special Report on Global Warming of 1.5ºC [Online]

 Available  Availab le at: at: www www.ip .ipcc. cc.ch/ ch/sr1 sr15/ 5/ (Acc (Access essed: ed: Sep Septem tember ber 2020) 8) Mercator Research Institute on Global Commons and Climate Change (2018) That’s how fast the carbon clock is ticking [Online] Available at: www.mcc-berlin.

step-by-step-guide/ (Accessed: September 2020) 11) Anon  Anon (20 (2019) 19) UK Structural Engineers Declare

 [Online] Available Climate & Biodiversity Emergency  [Online] at: www.structuralengineersdeclare.com (Accessed: September 2020) 12) British Standards Institution (2016) PAS 2080:2016

Carbon management in infrastructure, London: BSI 13) Derwent London (2020) Release of Net Zero Carbon

www.derwentlondon.com/  m/  Pathway [Online] Available at: www.derwentlondon.co media/news/article/release-of-net-zero-carbon-pathway (Accessed: September 2020)

net/en/research/co2-budget.html (Accessed: September net/en/research/co2-budget.html S eptember 2020)

14) Anon (2020) Landsec’s Of fi  fice   e 1.0 aims c for net zero fi  rst [Online] Available at: www.

9) World Green Building Council (2017) Global Status

constructionmanagermagazine.com/landsecs-offi ce-10-aims-for-net-zero-first (Accessed: September 2020)

Report 2017 [Online] Available at: www.worldgbc.org/ 

news-media/global-status-report-2017 (Accessed: September 2020)

10) Science Based Targets (s.d.) Step-by-step guide

[Online] Available at: https://sciencebasedtargets.org/ 

12 October 2020 | thestructuralengineer.org

15) Greater London Authority (2020) New London Plan

[Online] Available at: www.london.gov.uk/what-we-do/  www.london.gov.uk/what-we-do/  planning/london-plan/new-london-plan (Accessed: September 2020)

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Opinion Climate emergency Planning application Parametric procedures procedur carbon es benchmarking

 

3.Lean design

What do we mean by effi ciency? A holistic approach to reducing embodied carbon Ben Gholam describes Gholam describes the development by Price & Myers of a parametric benchmarking tool to allow engineers to produce scheme designs with the lowest embodied carbon. Introduction Effi ciency is something that we all strive to achieve as designers, but it is also something that is very diffi cult to define. Some define the effi ciency of a structure in terms of its cost and an d programme, while others focus on utilisation of members, or the overall amount of material per m2. However, However, in the face of the global climate emergency, we also need to consider a building’s whole-life carbon, which includes its embodied, as well as operational, carbon.  Architects, MEP engineers and sustainability consultants have, in recent years, been very successful in reducing operational carbon. This has been driven by both legislation and the financial savings to the client available from reduced energy bills. These legislative mechanisms do not currently exist for materials, which can also be so cheap in relation to the overall construction cost that there is often little financial incentive to make reductions.  As part of a consortium with with the University of Cambridge, the Steel Construction Institute and William Hare Group, Price & Myers recently completed an Innovate UK-funded study into the effi ciency of steel-framed buildings in relation to both cost and carbon. The study showed that focusing on the optimisation of individual members is not always the best solution to minimising embodied carbon, and that more focus needs to be placed on optimising highlevel factors such as grid spacings, foundation types and flooring types.  This project led us to create a parametric benchmarking tool, aimed at ensuring our engineers can rapidly produce scheme designs that represent the option with the lowest embodied carbon for the clients and architects we work with, while ensuring the relative costs can be assessed. This article summarises the work that led us to this

15 1: Governing utilisation ratios of beams, plotted as % of total mass of frame îFIGURE

   )    %    ( 10   n   o    i    t   c   a   r    f   s   s   a    M 5

0    ]    5    0  .    0   ;      0    [

   ]    0    1  .    0   ;      5    0  .    0    [

   ]    5    1  .    0   ;      0    1  .    0    [

   ]    0    2  .    0   ;      5    1  .    0    [

   ]    5    2  .    0   ;      0    2  .    0    [

   ]    0    3  .    0   ;      5    2  .    0    [

   ]    5    3  .    0   ;      0    3  .    0    [

   ]    0    4  .    0   ;      5    3  .    0    [

   ]    5    4  .    0   ;      0    4  .    0    [

   ]    0    5  .    0   ;      5    4  .    0    [

   ]    5    5  .    0   ;      0    5  .    0    [

   ]    0    6  .    0   ;      5    5  .    0    [

   ]    5    6  .    0   ;      0    6  .    0    [

   ]    0    7  .    0   ;      5    6  .    0    [

   ]    5    7  .    0   ;      0    7  .    0    [

   ]    0    8  .    0   ;      5    7  .    0    [

   ]    5    8  .    0   ;      0    8  .    0    [

   ]    0    9  .    0   ;      5    8  .    0    [

   ]    5    9  .    0   ;      0    9  .    0    [

   ]    0  .    1   ;      5    9  .    0    [

Member utilisation

stage and our findings on the way.

Defining effi ciency  Determining the amount of material in a frame is relatively straightforward with modern building information modelling (BIM) tools, but assessing utilisation ratios (URs) requires a bit more work.  To  T o do this, the first phase of the study1 involved the collection of data for over 3500 beams from 30 projects, and the back-calculation of their URs. Figure 1 shows the governing UR plotted against the fraction of the total mass of the beams (with UR = 1.0 being a 100% effi cient member).  The graph indicates that less than 20% of the measured structural mass was mobilised beyond 80% utilisation, and that there is a clear drop-off  after  after 80–85%. While the need to select

14

the most suitable section from a list of universal sizes means that, in practice, ‘full’ utilisation is often not achievable, this drop-off  indicated  indicated that designers were either heavily rationalising sizes for procurement or detailing reasons, or were hesitant to push designs right to the limit, potentially for fear of future changes. It is worth noting that, overall, this showed a cumulative 40% underutilisation in terms of material mass. The conclusion here is that there is clearly a lot to be gained in terms of material effi ciency by pushing the designs of beams closer to their full capabilities.

Utilisation vs geometry   This data related to individual individual beams, but logic dictates that there should be a direct relationship between the

October 2020 | thestructuralengineer.org

 

benchmarking   Climate emergency  Parametric carbon benchmarking

 

overall utilisation of a floorplate and the embodied carbon. To demonstrate that this is not necessarily the case, consider two options for a simple three-storey ~4000m2 commercial building. Option  A (Figure 2) has 2) has a typical span of 15m, with all beams designed at maximum UR (say 99.9%). Option B has the more typical value of 80–85% (Figure 3) but 3) but has extra rows of columns decreasing the grids to 7.5m in each direction.

 The ability to influence this outcome changes as a project progresses. Optimising the members in Option B could be done right up to the fabrication process with little impact on the overall design (a ‘local’ factor), whereas changing the grid would have a wideranging impact and would need to be done as early as possible (a ‘global’ factor).  

 A crude embodied carbon estimate estimate (for the steelwork only) gives 100kgCO2e/  m2 for Option A, but only 40kgCO 2e/  m2 for Option B. In this example, the building that has been optimised still has an embodied carbon 2.5 times higher than the one that hasn’t. (If we decide to optimise Option B and reduce steel by 15% as above, this value increases in creases to almost three times higher.) The grid has a much more significant impact on the material use and the carbon figure than the optimisation.

Decision-making

We started listing all decisions that could influence effi ciency of both individual beams and overall floorplates, at all project stages, and separated them into two distinct categories (Figure 4). 4).  A diff erent erent set of drivers in fluences the outcome of each of these, and as structural engineers, we find many of these are often outside our control once the design has passed a certain point – with cost, programme and procurement taking precedence and usually dictating

2: Option A for typical offi ce building, with all beams designed to full utilisation îFIGURE

THE GRID HAS A MUCH MORE SIGNIFICANT IMPACT IMP ACT ON THE MATERIAL USE  AND THE CARBON CAR BON FIGURE THAN THE OPTIMISATION the global factors. Coupled with the pressures of design fee and programme, the outcome is often a design that fulfils the brief but sacrifices structural effi ciency – with the engineer limited to being able to adjust the local factors towards the end of the design process (Figure 5). 5). This is a reactive process which – as we’ve shown – has the potential to make reasonable savings but may not allow the engineer to unlock the optimum design.  

Interaction  Altering some of these global global factors will typically lead to direct savings – such as lower imposed loads. However, some global factors are far more interconnected. Possible examples include: Ò| a reduction of dead loads resulting in lower foundation and column loads, but increased problems with vibration performance or uplift from wind Ò| an increase in structural zones and subsequent building height leading to lighter floor beams, but increased wind loads on the stability systems and cladding quantities Ò| a decrease in column grid reducing materials in the floors, but increasing overall materials (or costs) due to the increased numbers of columns and foundations required.    Therefore, a holistic approach approach that considers the relative impacts and interactions of all possible decisions relating to the global factors listed above needs to be taken. If done at a suffi ciently early stage, this can influence the design brief, allowing the maximum potential for savings in materials/  embodied carbon throughout the design process (Figure 6). 6).  There is likely to be a single or limited range of options that provide the optimal balance between a project’ project’s s cost and embodied carbon, and we needed a means for determining these. One option would be to compare against benchmarked data for similar completed buildings. This is possible, but to ensure suffi cient data to cover all

3: Option B for typical offi ce building, with all beams designed to typical utilisation îFIGURE

   A    D    I    H    S    I    I    J    N    U    H    S  

15

thestructuralengineer.org | October 2020

   

Opinion Planning application Parametric procedures procedur carbon es benchmarking Climate emergency

 

GLOBAL FACTORS

LOCAL FACTORS

 Column grid  Material choice Ò| Foundation type Ò| Imposed loading Ò| Structural depth Ò| Fire rating

 Material strength  Member size Ò| Member type Ò| Connection type Ò| Cells/openings Ò| Fire protection

Ò|

Ò|

Ò|

Ò|

ëFIGURE

a functional prototype, able to output rapid comparisons for steel-framed superstructure options. It became known as PANDA (Parametric Analysis & Numerical Design Assessment). After realising its potential, we decided to apply for additional Innovate UK funding to continue the work into a second phase.

4:

Breakdown of design decisions into those considered ‘global’ and ‘local’

DESIGN I BRIEF I

DESIGN BRIEF

3

LOCAL OPTIMISATION

DESIGN G

GLOBAL OPTIMISATION

çFIGURE

5:

Simplified illustration of typical design process

LOCAL OPTIMISATION

1 2 3 4 6: Revised design process, showing how early-stage optimisation could a ffect design brief ìFIGURE

scenarios, thousands of detailed cases would be required. A previous article in The Structural Engineer discussed the challenges of assembling a dataset of 80 benchmarked projects2 – and this work would have to be repeated many times over to achieve suffi cient numbers of examples. We considered creating a large database of hypothetical structures, acting as a quick reference guide to the optimal grid under certain conditions. However,, the grid is not the only However consideration, and when other key global decisions such as material choice and foundation type are factored in, the number of potential scenarios needing to be assessed quickly becomes commercially unmanageable – which is where the benefits of parametric analysis come in.

DESIGN

OUR SOLUTION WAS TO CREATE A PARAMETRIC BENCHMARKING TOOL, ENABLING RAPID  ASSESSMENT  ASSESSME NT OF ALL POTENTIAL OPTIONS îFIGURE

7:

Representation of massing input within software

PANDA tool Our solution was to create a parametric benchmarking tool, enabling rapid assessment of all potential options for any given situation. Within a few months of starting development, we had

16

 The tool has two parts: a design algorithm, and data comparison. In the design algorithm, the user inputs a simplified, orthogonal representation of the structure (Figure 7), 7), and then sets parameters which cover a broad range of both global and local factors, including maximum/minimum grid spacings, loadings, material types and geotechnical data. The algorithm then assesses all possible combinations of all the various factors and carries out a full structural design for each. Each valid design results in a detailed material and task list which is then run through a bespoke data model to assess the cost and embodied carbon of each option. The carbon data is based on the current (v3.0) ICE database3, with some adaptations made by the Cambridge team.  The cost model is being overseen overseen by one of the UK’s leading quantity surveying companies to ensure relevance to the current market. All data within the tool is fully customisable to ensure it can be adapted as the needs of the industry alter over time.  The software compares compares all these results in a graphical output (Figure 8), 8), clearly showing the variation between the relative cost and embodied carbon for each option. The results can be viewed in terms of a wide range of variables

October 2020 | thestructuralengineer.org

 

Parametric carbon benchmarking  benchmarking  Climate emergency 

(decking type, grid spacing, etc.) and can be filtered as necessary to remove unwanted results.  The tool has been developed to enable comparison of steel, concrete and timber frames over a variety of diff erent erent foundation types and is due to be launched across our practice later this year. Our engineers will use this tool at early conceptual stages. Using basic information on massing, loading and ground conditions, an output report for a simplified version of the building can be produced within minutes. The e ff ects ects of varying individual or multiple factors can then be rapidly assessed and quantified.

and materials, featuring both existing and new technologies. However However,, for the foreseeable future, high-carbon materials such as steel and concrete will remain an essential part of the mix. We therefore need tools such as PANDA to ensure we design as carbon-effi ciently as possible, while still meeting fee, programme and cost constraints. We will also need to liaise with clients, contractors and the rest of the design team to challenge decisions that result in things being done ‘the way we always do them’, and persuade others to pursue lower-carbon grids, loading and materials.  The greatest potential we we have for influencing the final outcome is by

 The aim is that the fundamentals of the initial scheme design – the global factors which play such a key role in the eventual carbon figure – will be set at the best possible values, ensuring that our engineers are working to a design that is as effi cient as it can be under the parameters of the design. While this is not intended to be a full design tool and doesn’t cover the intricate geometries often found on real projects, the level of detail provided will be suffi cient to enable the generation of benchmarking values for cost and carbon. Any changes or developments to the scheme can be assessed against this initial benchmark, ensuring that the design team is confident about the impact of all decisions.  

ensuring the correct decisions are made in the critical early stages. We must therefore also ensure we are given the opportunity to feed into the design brief to enable this4. Optimising for cost and optimising for carbon are not mutually exclusive, and with better ways of quantifying and assessing the impact of the decisions made in designing a structure, we will be much better placed to advise the rest of the team and ensure our buildings can be as effi cient as possible.

Impact and next steps  Achieving true net-zero will require require a huge step change in construction methods

Ben Gholam CEng, MIStructE

8: Graphical output from prototype parametric tool, showing cost vs embodied carbon for typical building in Fig. 7 and highlighting deck type variable ëFIGURE

17

 

 Acknowledgements  Acknowle dgements  The author would like to thank Dr Cyrille Cyrille F. Dunant, University of Cambridge; Dr Hannes L. Gauch, University of Cambridge; Ian Flewitt CEng, MIStructE, Price & Myers; Will Rogers-Tizard CEng, MIStructE, Price & Myers; Dr Stathis Eleftheriadis, University College London  / Price & Myers; Dr Michal P. Drewniok, University of Cambridge; Jonathan Davis IEng, AMIStructE, William Hare Group; Michael Sansom, Steel Construction Institute.  

REFERENCES 1) Dunant C.F., Drewniok M.P., Eleftheriadis S., Cullen J.M. and Allwood J.M. (2018) 

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[email protected]

Ben Gholam is a Structural Engineer at Price & Myers in London. For further information about the PANDA tool, visit www. pricemyers.com/news/parametric-

benchmarking-tool-for-embodied or contact Ben carbon-e ffi ciency--24  ciency--24 or at [email protected] .

‘Regularity and optimisation practice in steel structural frames in real design cases’, Resour., Conserv. Recy ., ., 134, pp. 294–302 2) Gholam B. (2020) ‘We signed the climate

declaration – now what? Lessons from counting carbon’, The Structural Engineer,  Engineer,  98 (7), pp. 28–30 3) Circular Ecology (2019) ICE Database,  Database,   V.3.0 [On  V.3.0 [Online line]] Avail Available able at: htt https:/ ps://  /  circularecology.com/embodied-carbonfootprint-database.html (Accessed: September 2020) 4) Algaard W. (2020) ‘Persuasion and

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influence in a climate emergency’, The Structural Engineer , 98 (9), pp. 10–12

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Opinion Climate emergency Planning application Rationalisation procedures procedur versus es optimisation

 

3.Lean design

Rationalisation versus Rationalisation optimisation – getting getting the balance right in changing times Ian Poole explores Poole explores ways to improve the utilisation ratio of designs, and encourages engineers to challenge assumptions that favour rationalisation over optimisation. Introduction

Reasons for low utilisation

UK structural engineers declared a climate emergency in 2019, with over 170 signatories committing to radical changes to tackle the climate crisis (www.structuralengineersdeclare. com).. This article focuses on one of the com) key commitments that the signatories agreed to address: Ò| Minimise wasteful use of resources in our structural engineering designs, both in quantum and in detail.

Risk mitigation  The reasons structural engineers often cite for not designing to 1.0 utilisation are the assumption of error (on site or in the design), and the need to cover c over design uncertainties or unknowns, which means using material as risk mitigation. While this approach is reasonable, it doesn’t consider the bigger picture, in that using additional material increases carbon emissions, which accelerates climate change and increases the risk to the livelihoods of the global population.  The approach is also circular, circular, in that if contractors know designs have spare capacity,, there is little pressure to get capacity things right. Finally, risk and uncertainty are mitigated in design codes using partial factors of safety, applied to both the loads and the materials that we use.  These codes exist to definitively justify that a design is safe, without the engineer making any extra allowance.

 This commitment infers that we are currently producing wasteful designs. Indeed, most practising structural engineers come to realise that wastefulness is inherent in how we design, and that it is mostly intentional. Wastefulness is a by-product of ingrained behaviours in the industry involving designers, clients and contractors, whereby using additional material has allowed us to improve quality,, save time, and reduce overall quality cost – the three key requirements from any client. However, there is now a fourth variable, carbon, which designers must consider (Figure 1). 1).

îFIGURE

1: Amended

project management triangle for climate emergency

It is a tough leap for engineers to make, but we are now unwittingly in a position where, when designing a building, we are not only responsible

What is the problem?  The study presented by Gholam1 in this issue found that structural engineers typically design to a maximum utilisation ratio of 0.8, with average utilisations of approx. 0.6. A white paper produced by the Structural Engineering Institute in the USA reported an even lower average utilisation of 50% in steel buildings 2.  Assuming a linear relationship between utilisation and material use, these papers suggest that structural designers are using somewhere between 20–50% more material than necessary. Given this, optimising our designs appears to off er er a significant and achievable opportunity to realise the commitment above.

for the health and safety of those who construct and use the building, but also for the health and safety of the global population due to the consequences of construction on carbon emissions and climate change. Rationalisation While risk mitigation may explain why designers waste up to 20% of material (by generally designing to a maximum utilisation of 0.8), it doesn’t explain why a further 20% is wasted (by generally designing with an average utilisation of 0.6). This can be explained by rationalisation, which will be the focus of this article. Rationalisation is the process whereby members with similar geometries and load actions are grouped together. This is seen to have various advantages, principally: Ò| simplifying the design process: reducing the number of calculations, simplifying co-ordination, minimising eff ects ects of change, and hence saving time and cost Ò| simplifying the construction process: reducing the number of unique sections and connections, reducing the risk of error, error, increasing repeatability,, and hence repeatability hen ce saving time and cost. It is important to note that the increased material cost due to rationalisation is generally small compared to labour cost savings and revenues associated with reduced programme times. On a recent project that the author worked on, the total material cost was approximately equal to just one month’s revenue from the operational building.  This presents presents a challenge that that sets the construction industry apart from other similar industries (e.g. aviation): to reduce material without the financial incentive to do so.

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October 2020 | thestructuralengineer.org

Rationalisation versus optimisation optimisation   Climate emergency 

 

 

Rationalisation interrogated If rationalisation requires an additional 20% of material (and carbon), we should be certain it is providing the benefits we assume. After all, knowledge is generally passed on, and as discussed by Rosling3, our understanding of the world often lags behind the times, defined by outdated knowledge and assumptions. Rosling asserts that we must challenge the idea that today’s culture must also have been yesterday’ yesterday’s s and will also be tomorrow’s. To this end, in the climate emergency, previous reasons and arguments must be discounted, today’s today’ s reasons and an d arguments must be informed rather than assumed, and we must endeavour to shape and predict future trends (due to the time lag between design and construction).  The following points summarise summarise the key changes to our working culture that reduce the need for rationalisation in our design: Ò| Designers have the tools available to eliminate long calculations and effi ciently design members using powerful computer-aided design (CAD) software. Ò| Changes can be quickly incorporated and calculations re-run with the aid of analysis software, and do not require changes to large quantities of paperwork as in the past. Ò| Coordination using building information models (BIM) has removed the need to simplify details,

  provide flat soffi ts, ensure equal beam depths, etc. Ò|  The  The use of BIM allows us to link design models and CAD software more effi ciently, reducing the consequence of structural designs on production and checking of drawings.    Altogether,, the benefits of  Altogether rationalisation to the designer are minimal given the tools available, providing there is reasonable allowance of time in the programme. The rationalisation benefits therefore must be realised

ëFIGURE

2: Design

model used for case study

in the construction stage. This is the assumption that most young engineers are taught when they begin undertaking design work, based on historical truths. However,, are these reasons still valid in a However rapidly changing industry?

WE ARE ALSO RESPONSIBLE FOR THE HEAL HEALTH TH AND SAFETY OF THE GLOBAL POPULATION DUE TO THE CONSEQUENCES OF CONSTRUCTION ON CARBON EMISSIONS AND CLIMATE CLIMA TE CHANGE 19

Case study   The case study presented is a longspan, single-storey, steel structure constructed in 2019. The final design (Figure 2) comprised 2) comprised 2500t of primary steelwork (roof steel ~125kg/  m2 with ~70m spans), and was highly rationalised to focus on minimising construction time on site (achieved in 10 weeks). Structural optimisation was therefore compromised due to the following design decisions:  A small number of of unique sections Ò|  A were used to increase repetition and minimise unique connections. It was assumed that this would minimise site works and the risk of error leading to programme delays.  Truss depths were were limited to avoid avoid Ò|  Truss vertical splices – this was estimated to make the design four times faster to erect due to off -site -site preassembly minimising site works. However, it compromised a greater structural depth which would have improved the effi ciency of the structure (in some areas, vertical clearances within strict building height requirements also restricted structural depth). Ò| Load combinations had to consider gravity loads, uplift due to wind through dominant openings, and large point loads acting at various locations. As complexity in loading increases, form-finding solutions become more complex and incur added time to design and construct.

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Opinion Planning application Rationalisation procedures procedur versus es optimisation Climate emergency

   This wasn’t to say that that the engineers did not try to create an effi cient structure. In fact, through challenging the brief, which specified no internal columns (as would be typical for this type of building), the design team realised an opportunity to introduce an internal column without compromising the functionality of the building.  The driver of this change was a saving in cost (estimated £1.5M) and programme (estimated six weeks).  Although not quoted as a reason reason at the time, the 600t of steelwork saved also equated to a saving of over 1000t of CO2e. Ultimately,, despite achieving the brief Ultimately and off ering ering additional value, the design conformed to the wastefulness reported in research studies referenced earlier, with an average utilisation of 0.56, owing to the large amount of rationalisation.  This case study, study, completed following construction, looks at the opportunities that might have allowed for i mproved utilisation and the possible eff ects ects on construction (cost, programme, quality) as provided by the steelwork contractor. contractor.   Opportunities  A total of 19 opportunities opportunities were identified in the case study study.. These could be generalised into three categories:   Challenging the codes Options to ‘design for performance’ rather than to codes were considered, c onsidered, such as reducing the partial factor of safety applied to the self-weight of steel and relaxing deflection criteria. However However,, it was decided that the design should conform to codes for the optimisation study.   Optimising form Optimised form is known to o ff er er vast bene fits, as outlined in the ongoing BuildOpt4 research project and in the article by Gholam1, so many opportunities related to optimised form, such as modifying truss types, geometries, grid spacings and restraint systems, were considered. However,, these were not investigated, However in vestigated, due to time limitations and the di ffi culty of quantifying other impacts. For example, increasing truss depths would increase cladding, internal volume (heating and lighting), and aff ect ect compliance with cranage requirements.   Optimising utilisations  The form of the structure was was therefore unchanged, and the aim was simply to optimise the chosen form through the removal of rationalisation, while

directly with the contractor contractor,, minimises additional time spent designing unique connections that may have previously been assumed to be an issue.    Assessment  Assessme nt  The final part of the study would require an assessment of the structure’s structure’s as-built ‘rationalised member utilisation’ and the attempted ‘optimised member utilisation’ solution, using a few iterations of the

minimising the impact on programme, as assessed by the steelwork contractor. contractor.  This was achieved through the following following approaches:   Designing spliced sub-assemblies independently  As splice locations were specified in the truss design, it would take minimal time to design each spliced section independently.. This allows reductions in independently sections as forces reduce along the truss length. When adopting this method, a sensible approach is required where the engineer must consider the connection types (Figures 3 and 4). 4).

design model to approximate the latter.  The material reduction was estimated to be 34%, which closely aligns with the increase in average utilisation ratio (0.30) (Figures 5 and 6). Critically,, 6). Critically the contractor feedback was that the optimised solution would have minimal impact on programme time. Ultimately, the material saving from optimisation would equate to approx. 900t of steel, and more pertinently to a CO2e saving of almost 1500t*. For context, this is equivalent to the annual carbon footprint of approx. 180 people in the UK 5, or 900 people taking a return flight from London to New York 6. More scarily, taking a semi-quantitative prediction of the eff ect ect of current carbon emissions on future populations and the ‘1000t rule’, this level of saving is likely to prevent a premature death relating to climate change in the future7.   Reflection  This study found that many arguments made in the past for rationalisation do not align with current best practice, both in design and construction. Further, assumptions made on the benefits of rationalisation in the design stage were in many cases unfounded. Given the findings reported in the publications referenced earlier relating to average utilisations, it is likely that many other designers are making similar

  Increasing unique sections forming truss internals, bracing and tie members Increasing the number of unique sections in our designs to reduce material is encouraged due to much higher levels of quality control and availability of steelwork than in the past, when worse quality control (leading to error) and more common lack of supply (causing delays) would require increased rationalisation.  There is also a huge range of of section capacities within similar section geometries, which allow for similar connections to be used even if members diff er. er. Finally, the ease of connection design, especially if design models are shared

decisions based on outdated knowledge and assumptions. This unnecessary rationalisation is wasting material, which in turn is needlessly pumping carbon into the atmosphere. It should be noted that this study takes a relatively soft approach to ‘optimisation’, in that the opportunities were only considered if they had minimal eff ect ect on design time and construction programme, such that they would reasonably meet client requirements on the project. Indeed, many may argue that this doesn’t go far enough, and that projects today should prioritise reducing carbon over cost and programme considerations, in which case there would be further opportunities (touched

ìFIGURE

3: Compression splice – connection would not be compromised due to differing incoming sections

4: Tension splice – additional packing and jigging will be required if incoming sections differ, increasing time and cost ìFIGURE

* This figure considers only carbon associated with Scope A1–A3 steelwork, assuming a value of 1.64kgCO 2e/kg steel, which is adopted from t he Inventory of Carbon and Energy database using average recycled content of 59%, as reported for European steel. Further carbon savings would be expected due to reduced transport (A4), reduced site works (A5), and reduced concrete in the substructure and foundations.

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October 2020 | thestructuralengineer.org

Rationalisation versus optimisation optimisation   Climate emergency 

 

WE MUST CHALLENGE ANY  ASSUMPTION  ASSUMPTIO N MADE IN THE DESIGN ST STAGE AGE WHERE RATIONALISATION IS ADOPTED OVER OPTIMISATION

   T    N    E    C    R    E    P    S    S    A    M    Y    B    L    E    E    T    S

0–0.2

0.2–0.4

0.4–0.6

0.6–0.8

0.8–1.0

UTILISATION RATIO ìFIGURE

5: Rationalised member utilisation

REFERENCES 1) Gholam B. (2020) ‘What do we mean by effi ciency? A holistic approach to reducing embodied carbon’, The carbon’, The Structural Engineer , 98 (10), pp. 14–17

   T    N    E    C    R    E    P    S    S    A    M    Y    B    L    E    E    T    S

2) Webster M.D. (2020) Ach  Achievi ieving ng Net Net  Zero Embo Embodied died Car Carbon bon in Stru Structu ctural ral Materials by 2050 [Online] Available at: https://seisustainability.files.wordpress. com/2020/03/achieving-net-zero.pdf (Accessed: November 2020) 3) Rosling H. (2018) Factfulness: Ten

0–0.2

0.2–0.4

0.4–0.6

0.6–0.8

0.8–1.0

6: Optimised member utilisation ëFIGURE

UTILISATION RATIO

on above) which would lead to material reduction. Finally, this study has been possible due to the collaboration between designer and contractor contractor.. Collaboration allowed carbon savings to be made on the project (e.g. through sharing design models to aid connection design), and the valuable lessons that form the basis of this article to be learned. Revisiting the design after construction to learn lessons was hugely beneficial, and is something we should do more often to improve the industry and address the cli mate emergency.  

Conclusions  The conclusion conclusion from from this this study is that we we must challenge any assumption made in the design stage where rationalisation is adopted over optimisation, to ensure any assumed benefits are correct and to justify additional use of material and carbon.

In most cases, given the tools available to us in the present and the future, and the urgent need to reduce carbon consumption, the balance must shift dramatically from rationalisation towards optimisation.  

4) Computational Design Optimization of Building Structures website (s.d.) [Online]  Availab  Ava ilable le at: at: www www.bui .build-o ld-opt.o pt.org/ rg/ (Acc (Access essed: ed: September 2020) 5) Data extrapolated from: Global Carbon  Atlas (s.d.)  Atlas (s.d.) CO 2 emissions  emissions [Online]  [Online] Available at: www.globalcarbonatlas.org/en/CO2emissions (Accessed: September 2020) 6) Calculated using: Carbon Footprint (s.d.)  Flight carbon footprint calculator [Online] Available at: https://calculator. carbonfootprint.com/calculator.aspx?tab=3

 Acknowledgements  Acknowle dgements I must thank Pierre-Louis Morcos and Angus Cormie for their valuable contributions in undertaking this study.  

Reasons We’re Wrong About the World –  and Why Thin Things gs Are Are Bett Better er Than Than You Thin Think, k,   London: Sceptre

(Accessed: September 2020)

HAVE  YOUR  YO UR SAY  SA Y 

7) Parncutt R. (2019) ‘The Human Cost

of Anthropogenic Global Warming: SemiQuantitative Prediction and the 1,000-Tonne Rule’, Front. Psychol ., ., 10: 2323

FURTHER READING

Ian Poole MEng [email protected]

Ian a structural engineer atthe Mottis MacDonald. He sits on Institution’s Sustainability Panel and is active in LETI, contributing to and reviewing its Embodied Carbon Primer.

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Orr J., Copping A., Drewniok M., Emmitt S. and Ibell T. (2018)  MEICON: Minimising

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Energy in Construction: Survey of Structural Engineering Practice Report  [Online]  [Online]  Availab  Ava ilable le at: at: htt https:/ ps://doi. /doi.org/1 org/10.1 0.1786 7863/  3/  CAM.35178 (Accessed: September 2020)

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Professional guidance

Business Practice Note | No. 35

 

BUSINESS PRACTICE NOTES

No. 35

have been developed by the Institution’s Business Practice and Regulatory Control Committee to provide guidance on aspects of running a practice and project management.

Dealing with

www.istructe.org/bpns

unauthorised changes on site In this note, Simon Pitchers provides advice to structural engineering professionals on how to proceed if they become aware that an unauthorised change to the design has taken place on site.

Causes of unauthorised change  An unaut unauthoris horised ed chang change e on site may be an inadvertent inadvertent misinterpretation  misinterpretation of the design, due to: Ò| ambiguity, lack of clarity, or absence of a design for a particular element Ò| failure properly to consider it.  Alternatively  Alternativ ely,, it may be a deliberate incorrect implementation of the design: Ò| because it could not be constructed as designed Ò| to make the work easier, faster or cheaper to construct. Contractor fraud or deliberate concealment concealme nt by unscrupulous timing of inspection visits have been used to hide unauthorised changes.

Potential implications Unauthorised changes changes can give rise to conflicts of interest, particularly in design-and-build projects. They can compromise stability, durability, robustness, safety, repairability, maintainability, capital or whole-life cost, professional ethics (particularly where safety is compromised) and the requirements requirem ents of other disciplines and approving authorities. Example: A change change that does doesn’t n’t compromise your structural design could contravene the requirements of the architect (perhaps by introducing a cold bridge) or warranty providers (perhaps by deviating from the requirements of the NHBC Technical Standards).

whether the issue is within your scope. Notwithstanding this, you should quickly assess whether the change compromisess design parameters and compromise consider whether it was really necessary.

Insurance notification If there is any associated risk of a claim being made against you, notify your professional indemnity (PI) insurance brokers without delay, otherwise you risk being left without full/any PI cover.  Avoid assumin assuming g that that the the cost cost of dealing with an unauthorised change which appears to be the fault of another party (such as the contractor or a diff erent erent designer) will not develop into a claim against you. Other parties may disagree with your view and withhold fees. Look carefully and critically at your own information, as under the scrutiny of lawyers, black and white situations can become grey. Example: Reinforcement had been incorrectly installed on site. However, the designer’s drawings were ambiguous, so the designer was deemed liable for the error.

Contractual position Understand your contractual responsibilities on site and any requirements to act in a certain way if you identify an unauthorised change.  You  Y ou may may be be requir required ed to to report report to an an identified party, in a specific way, within a certain timescale. Keep your PI insurers informed. They may suggest ways of providing contractual notifications without prejudicing your position.

Initial assessment If you become aware of an unauthorised change, and the change could cause a plain and obvious danger to people’s health and safety or to the property itself, you have a duty to warn, in strong and clear terms, irrespective of

Determine implications If the change cannot be resolved immediately,, prioritise determination of immediately the probable implications of the change.  Advise the clien clientt and and all member memberss of the design and construction team of the

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change and ask them what aspects of their contractual responsibility it aff ects. ects. structurally rally inno innocuou cuouss Example: A structu unauthorised change, such as permitting foundations to extend beyond their designed extent, might (perhaps unknown to you) compromise a planning condition, because the enlarged foundations now extend into a root protection zone. If another member of the team is better placed to resolve the unauthorised change – e.g. if its remedy is outside your project remit or discipline – then pass it to them for resolution.

Initial investigation  Take deta  Take detailed, iled, date dated d and and timed timed photographic and video evidence. Make written notes of all conversations that take place either in person or by phone.  The chro chronolo nology gy of even events ts often often beco becomes mes important later. Prioritise reaching a solution, but follow due process and resist pressure to cut corners to save time. If your contractual position allows it, talk to the site team as soon as the change is identified. If safety is being immediately compromised, compromised, your duty to warn may well override any contradictory contractual requirements and you may have to stop work and/or instruct immediate rectification. Explain the unauthorised change with sensitivity and in a spirit of cooperation. Find out whether the site team agrees that an unauthorised change has occurred – this may help to identify why it happened. Be prepare prepared d for initial resistance,, but this may soften when resistance people realise that the problem has been caught early, saving a more di ffi cult remedial scheme. It is occasionally possible to e ff ect ect an immediate resolution, saving everyone time and eff ort. ort.

October 2020 | thestructuralengineer.org

Business Practice Note | No. 35   Professional guidance

 

Example: Mis-positioning of signage was noted before a subcontractor had completed its work. The designer quickly liaised directly with the site team, which moved signs immediately, saving the cost of a snagging exercise and an additional visit by the subcontractor.  

Follow the trail If an unauthorised change has been identified in one element, consider whether it might be present elsewhere. elsewhere. Include in your proposals any investigation necessary to determine whether more elements have been aff ected. ected. Example: A resin anchor was identified as incorrectly fixed, the hole for the anchor not having been cleaned to the specification, reducing its tensile strength. Anchors already fixed at numerous other locations had to be investigated to check whether the same deficiency was present.  

Draft remedial advice Prioritise engagement with the team to help to consider the ramifications of: Ò| not implementing any remedy Ò| implementing a full remedy, returning the work to the original design erent Ò| implementing one or more diff erent remedies that will improve the position but will not return the work to the original design.   It is worth noting that remedial measures have to be reasonable and the law may not support an insistence on returning the work to the original design. Share your thoughts and ask the wider team if they believe a better way to resolve the problem exists. Include with your draft remedial options: Ò| the impact that each will have on the original design (e.g. reduced durability) | Ò from discussions with the team, very approximate programme and cost implications, including investigation, design, approval, construction and comprehensive independent scrutiny of remedial measures by you and any other disciplines aff ected. ected.   Write to all parties or an identified coordinating coordinatin g party as early as possible (normally within one or two working days), setting out the draft options. State clearly any uncertainty or assumptions made. Ask for direction.  An imperf imperfect ect but spee speedy dy respo response nse will serve the client better at this stage than one which is fully considered but late.

INDEPENDENT SCRUTINY IS OFTEN UNDERVALUED BY CLIENTS AND DEVELOPERS, BUT EXPOUNDING ITS  VIRTUES  VIRTUE S WILL HELP TO TURN THE TIDE OF OPINION Remedies falling short of original design  A remed remedyy that that falls falls shor shortt of the performance of the original design may be appropriate. Such solutions may invoke an associated compensatory consideration, recognising the impact that the resulting additional eff ort ort and shortfall in the resulting design will have on the client and other members of the team. Example: A  A compone component nt speci specified as hot-dip galvanised was incorrectly supplied blast-primed. It was accessible for painting in the finished building so, to avoid delay, which would have been expensive to the client due to a penalty clause, the client accepted the painted component together with a consideration that would cover the cost of the consultant’s advice on a paint specification and painting on a number of occasions over the life of the building.  

 

 Avoid  Av oiding ing pro proble blems ms Unauthorised change is a major problem, resulting in unnecessary waste and risk. The most eff ective ective ways to avoid unauthorised change are to: Ò| get your designs checked by a third party (and be grateful for any issues that are identified – they are better resolved now than on site) Ò| champion comprehensive independent scrutiny of all site activities.. activities  

Engineers thrive on solving problems, but if you do sort a problem out without first gaining formal client agreement to pay for your services, you will have diffi culties in getting paid for your extra work. Also, sadly, remember that being too helpful is one of the main causes of claims against engineers.  

Independent scrutiny is often undervalued by clients and developers, but expounding its virtues will help to turn the tide of opinion.    This note has has been prepared prepared by

Selecting and developing the remedial solution

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Implementation  Arrange to be  Arrange be able able to to undert undertake ake quickly any investigation proposed and, subsequently, inspections of the remedial work. Failing to implement your proposals in a timely manner could result in a claim against you, should you delay the contract.  All eleme elements nts of the the reme remedial dial sche scheme me should be inspected before they become concealed by follow-on trades. Make detailed records using photographic or video evidence and marked-up drawings. Implement a sign-off  system  system that identifies what you have inspected and are agreeing as satisfactory.  Avoid genera generalise lised d sign-o gn-off  statements  statements such as ‘the work inspected was excellent’ as this could be interpreted to mean you have inspected areas that are beyond your remit. Also note that the word ‘excellent’ implies a standard of work much better than ‘satisfactory’. Better is a phrase like ‘the  bar diam diamete eters, rs, posit positioni ioning ng and and cover cover at  [locatio  [loc ation] n] gene generall rally compli complied ed with with the speci fi  fication’ c   ation’.

Getting paid

Once a preferred option has been selected, develop it in detail with the team. All team members must check that the proposals will not detrimentally aff ect ect their design. A remedial scheme implemented without full consideration has the potential to undermine other parts of the design and to cause wide and serious issues. If, as you develop the remedial scheme specification, the cost and programme estimates deviate widely from your draft advice, immediately ask for direction. When the re-costed and reprogrammed remedial scheme specification is complete, including proposals for further investigation, issue it in draft and ask all other team members (including the client) for comment. Make

adjustments if necessary and then recirculate it asking for written approval from the whole team.  

HAVE  YOUR  YOUR SAY  SA Y 

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Simon Pitchers BSc (Hons), CEng, FIStructE on behalf of the Institution of

Structural Engineers’ Business Practice and Regulatory Control Committee. Members are reminded that they should always comply with the legislation of the region in which they are working and members should be aware of any jurisdictions specific to the region in which they are working. Business Practice Notes are provided as guidance to members, but do not form part of the Regulations and/or Laws of the Institution. All members are obliged to abide by the Code of Conduct.

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Professional guidance

COBie standard

 

 An introduction introduction to the COBie standard The Institution’ Institu tion’s s BIM Panel provides a brief overview of the COBie information exchange standard, which is intended to reduce interoperability issues between different software systems. Introduction COBie (Construction Operations Building information exchange) is a common standard for defining expectations for the information that needs to be exchanged throughout the whole lifecycle of an asset, i.e. the handover information required for relevant stages. Its main purpose is to help reduce interoperability issues between diff erent erent systems, e.g. when transferring design data from a 3D model into an asset management system. COBie data providess an extracted view of the overall project information model (PIM) for a facility. The PIM contains the relevant design and as-built information about the objects/assets that make up the facility facility,, including relationships with all other assets.  The information held within a PIM will include the 3D models and all issued documents.  Therefore, it should should be noted that not not all information in the PIM will be contained in the 3D model. COBie can prove a useful tool for assuring the completeness and accuracy of the information being handed over. However, this relies on clear client requirements against which the information supplied can be compared and verified. The COBie standard (BS 1192-4:20141) does not specify this level of detail, it only provides the framework for writing these contract-specific requiremen requirements ts for BIM Level 2 projects. (Note that with the recent release of ISO 19650:20182, BIM Level 2 is now referred to as Stage 2 BIM. This brings UK terminology in-line with that of the international community.)  

Scope of COBie  The COBie standard standard covers temporary project project and permanent site information for a distinct operational unit – a facility facility.. This helps specify a historical record of the asset, covering what an asset is, where it is, how it relates to other assets, and key activity details, e.g. who produced the information and under which contract.  The standard is designed designed to reduce cost by removing the need to provide duplicate information and eventually eliminating the requirement to provide paper-based documentation. During design, COBie de fines a standardised output for accommodation,

1:  Scope of COBie in design, construction and handover  ë FIGURE

product and equipment schedules. During construction and handover, it provides standardised outputs for interlinked digital information for the operations and maintenance (O&M) manual (Figure 1). 1).  The COBie forma formatt follow follows s the the rules rules of a relational database. It is not a hierarchy but a set of related data. For example, spaces are related to the zone they are contained in and also related to the floor they are assigned to. This allows the data to be interrogated and viewed in diff erent erent ways.  A key key aim aim is to pro provide vide the info informa rmation tion tha thatt is

Examples of additional COBie information are listed below. The tables in Appendix  A of BS 11921192-4 4 state state whic which h of of these these are considered optional: Ò| Instruction – Table A.1  Assembly – Table A.13 Ò| Assembly Ò| Connection – Table A.14 Ò| Spare – Table A.15 Ò| Resource – Table A.16 Ò| Job – Table A.17 Ò| Impact – Table A.18 Ò| Document – Table A.19  Attribute e – Table A.21 Ò| Attribut fields

needed for follow-on activities. For example, for a simple repair an asset manager will need to know details of the manufacturer’s parts; however, for more serious problems the original design information may be required. This means COBie data will come from a wide variety of sources.  The nee needs ds for for COBie COBie will diff er er from project to project, so the full detail of what attributes are needed from whom should be speci fied in project-specific requirements at the outset.  

Ò| Coordinate – Table Ò| Issue – Table A.25

Content of COBie sheets

Production of COBie data

 The clie client nt shoul should define which COBie sheets are to be provided and what should be in each sheet. Sections 6 and 7 of BS 1192-4 set out the management, quality and implementation standards that should be followed. The requirements are colour coded to distinguish the parameter types (Table 1). 1). Table 2 indicates 2 indicates what information is contained in COBie asset sheets, while Figure 2 presents 2 presents a COBie component example.

When planning delivery of COBie data, it is important to understand and then specify the most appropriate data source in the BIM execution plan (BEP). It is rarely possible to source it all from a 3D design model. COBie information is usually compiled by several parties and needs to be federated into a single COBie spreadsheet by the information manager. Some of the COBie data includes

24

Ò| Picklists

A.22

– Table A.26.

  Responsibilities for populating these sheets need to be clearly defined based on the responsibilities for producing and managing the relevant information. For example, as-built and O&M information should be populated by the contractor or facilities manager.  

October 2020 | thestructuralengineer.org

 

COBie standard  standard  Professional guidance

2:  COBie component example based on  Appendix A of BS 1192-4 ë FIGURE

information that is the responsibility of manufacturers manufacture rs and contractors, such as serial numbers, parts lists and job details. Effi ciencies can be made if the project delivery plan (through the BEP) includes details on automated uploading of this information from the original source, instead of manual entry of information copied from documents.  The common standards standards used for Industry Foundation Classes (IFC), Uniclass 2015 and COBie mean that many software vendors, such as Autodesk, Bentley and Trimble, have developed export tools which allow design software to automatically export COBie data views.  The quality of this COBie data data relies on the designers and detailers complying strictly with the required naming standards when producing the source design models. However,, it is technically diffi cult to deliver a However compliant COBie IFC and it is not possible to do it without manual intervention.  The aim is to produce project information in a way that can automate the production of COBie data from the PIM. This means managing project information as structured data, not as unstructured information. (e.g. in a Word document). Failure to do so results in manual population of COBie information, which reduces the effi ciency of information exchange. COBie standards are based on the principles of object modelling, i.e. the information model describes the numerous things and their relationships to each other. other. Objects are not always physical things. Objects include ‘concepts’ such as a contract, a cost plan or an activity. An asset is any object, physical or concept, that adds value. One object can be vital to the definition of another object without being an immutable part of the other other.. For example, a steel beam within a frame needs to be erected and,

TABLE 1: Parameters for COBie sheets Expected

This field is expected

Reference or Picklist

References another sheet or populated from a picklist

 Application  Applic ation

Autofilled by authoring application

Requirable

Required by employer’s information requirements or digital plan of work 

 Additional  Additi onal

User-defined. Refer to Section 7.7 of BS 1192-4 for User-de suggested additional attributes

TABLE 2: Information contained in COBie asset sheets* Contact

Contact information – Example Table A.2

Facility

Information about the facility – Table A.3

Floor

Information on vertical levels – Table A.5

Space

A location for activity – Table A.7

Zone

A set of spaces sharing a specific function/attribute. Note that zones defining public/private access should be defined (BS 1192-4 Section 5.2.2) – Table A.9

Type

Information on types of equipment, products and materials – Table A.10

Component

Individually named or scheduled item – Table A.11

System

Set of components defining a service. Note that every distinct functional system should be included, whether containing manageable components or not (BS 1192-4 Section 5.2.2) – Table A.12

* All table references are to Appendix A of BS 1192-4

when erected, it needs to perform as part of a structural system that holds a building up. So, a steel beam can be part of the erection ‘assembly’ while also being part of the structural ‘system’.  The fact that the ‘assembly’ and the ‘system’ are both called frames can cause confusion. The importance of context when using a term is essential to maintain the clarity of the diff erent erent functions if, as in this example, common names are used. It should also be noted that current export

25

standards do not include ‘assembly’ and some MEP systems. When modelling, it is important to understand these principles to ensure that aspects of the information model are not produced in a way that creates inappropriate fixed hierarchies. For example, if a steel beam can only be reported on (searched for) as part of an assembly,, it will be hard to trace this beam assembly when searching for it as part of a structural steel system.

thestructuralengineer.org | October 2020

Professional guidance

COBie standard

 

COBie data standards COBie follows the same international data standards as those used by IFC and Uniclass 2015. COBie is a subset, or model view definition, of an IFC data schema documented by buildingSMART 3.  The underlying data dictionary which describes terms, vocabulary and attributes complies with ISO 120064,5. The standard for the basic ‘operating system’ to transport the information and data is ISO 167396. Uniclass 2015 is a unified classification for the UK industry covering all construction sectors. This has been developed by the NBS to comply with ISO 12006-2. It should be noted that Uniclass 2015 is an ongoing project that is currently updated around three a year. This means that itstimes use on a project needs clear version control.

REFERENCES

1) British Standards Institution (2014) BS 1192-4:2014 Collaborative  production  produ ction of of information information.. Ful fi  fi lling   employer’s employe r’s  information  informa tion exchang exchange e  requirements  requir ements using COBie COBie.. Code of practice, London:

BSI

 August 2020) 4) International Organization for Standardization (2015) ISO 12006-2:2015 Building construction. Organization of information  about constr construction uction.. Part 2: Framework for classi fi  fication, c   ation,

HAVE  YOUR  YOUR SAY  SA Y 

Geneva: ISO

2) British Standards Institution (2019) BS EN ISO 19650:2018 Organization and digitization of information  about buildi buildings ngs and and civil civil engineering works, including  building  buildi ng informatio information n  modelling  modelli ng (BIM). (BIM). Informatio Information n  management  manage ment using using building building  information  informa tion modelling modelling,,

London: BSI 3) BuildingSMART International (2020) IFC (2020) IFC Speci fi  fications c   ations Database

[Online] Available at: https://  technical.buildingsmart.org/  standards/ifc/ifc-schemaspecifications/ (Accessed:

5) International Organization for Standardization (2007) ISO 12006-3:2007 Building construction. Organization of information about construction works. Part  3: Framework Framework for objectobjectoriented information, Geneva:

[email protected]

@IStructE #TheStructuralEngineer

ISO 6) British Standards Institution (2020) BS EN ISO 16739-1:2020 Industry Foundation Classes (IFC) for data sharing in the construction and facility  management  manage ment industri industries. es. Data Data  schema,, London: BSI  schema

FURTHER READING BuildingSMART alliance (2020) Construction Operations Building information exchange (COBie) [Online] Available at:

www.nibs.org/page/bsa_cobie (Accessed: August 2020)

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Stone as structural material

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Technical

Stone as a structural material

 

Stone as a structural material. Part 4:

Contemporary stone buildingsloadbearing SCOTT BOOTE  BEng (Hon (Hons), s), CEn CEng, g, MIStr MIStructE uctE,,  AMICE   AMIC E 

 Associate  Associ ate,, Webb Webb Yate atess Engin Engineers eers,, London, UK MARK DAY   MEng (Hons)  MEng (Hons),, CEng, CEng, MISt MIStruct ructE  E 

 Associate  Associ ate,, Webb Webb Yate atess Engin Engineers eers,, London, UK

SYNOPSIS

Not all contemporary innovation is about exploiting digital fabrication or creating wild new forms. By applying a new way of thinking to traditional materials and craft, geometrically simple and innovative structures can be realised that are both elegant and environmentally ethical. Webb Yates, in conjunction with The Stonemasonry Company, has begun to develop a building system that would be a low-energy alternative to more common steel and concrete-framed structures. In this article, we hope to demonstrate how a creative approach to engineering design can utilise stone to exploit its inherent strengths.

STEVE WEBB  BEng (Hon (Hons), s), CEn CEng, g, MIStr MIStructE  uctE 

Director, Webb Yates Yates Engineers, London, UK

Introduction Stone is a high-strength and durable building material of considerable abundance. If it is sourced locally and lightly worked, it has very low embodied energy compared with other materials. It has high thermal mass, which is desirable even in cooler climates. Due to its historical precedence, stone is deemed highly desirable as a finishing material and yet, in recent times, it has tended to be used as a high-quality decorative product only.  To  T o demonstrate stone’s stone’s environmental credentials, with regard to embodied carbon, a simple comparison can be made. A 12m span stone beam (Figure 1)  designed for offi ce loading1 has a 1) carbon footprint of 778kgCO2e (carbon dioxide equivalent). An equivalent beam has a footprint of 893kgCO2e in timber (excluding sequestration), 1929kgCO2e in concrete and 3230kgCO 2e in steel with a composite concrete deck 2.  The aim of our research at Webb  Yates has been to find a new, practical and effi cient way to use stone as a standard primary structural component. We propose a building system that

   N    A    E    L    C    A    M    N    H    O    J

would be a low-energy alternative to more common steel and concreteframed structures. This research is in its early stages and this article outlines our initial thoughts and investigations.

Components and the modern building While loadbearing wall construction has many economic advantages, the desire for open-plan spaces in offi ces and public buildings, and for the ability to adapt and reconfigure the internal arrangements of residential buildings, has led to its decline in many typologies.  A flat-slab-and-column type

28

éFIGURE 1: 12m

prestressed stone beam

construction is a common structural arrangement for residential buildings, while a steel-post-and-beam construction is more common for offi ce buildings. For a new system to be useful, floor plates must meet the same criteria of optimum offi ce space and building height as these more common steel and concrete structures. Our proposal (Figures 2 and 3) is 3)  is for structures formed with three fundamental standardised components: | columns | beams | slabs.

October 2020 | thestructuralengineer.org

 

Stone as Cracking a structural of material concrete Technical Technical

 

Column and beam components would be formed with solid stone, perhaps reinforced or post-tensioned. Post-tensioned and reinforced stone structures are not unheard of 3, but are far from common. Our practice had been working in the design of traditional stone staircases, which are supported by a side wall, for several years when our client (The Stonemasonry Company) identi fied an opportunity to market free-spanning stone staircases. It was at this point that we began to investigate reinforcing and post-tensioning stone components in series. Having now built many reinforced and post-tensioned stone elements, it is clear that this is an economical and straightforward way to build.

for the external finish: brickwork and stone.  The general principle of the stone facade, as with most buildings, was to make the structure as e ffi cient as possible, to simplify installation and to reduce the space taken up by structure. In this instance, each column is designed to resist the load that is applied, leading to varying sizes throughout the facade, i.e. a larger load = a larger column. The iterative approach considers the natural load path, the eff ect ect of relative stiff ness ness of larger and smaller columns and the eff ect ect of the reduction in self-weight èFIGURE 2: Model of

stone building system

Columns 15 Clerkenwell Close is a mixed-use (residential and commercial) building located within the Clerkenwell Green Conservation Area in central London.  The building consists of a reinforced concrete stability core, with reinforced concrete flat slabs supported by a loadbearing stone facade (Figure 4). 4).  Architectural considerations included a desire to achieve an open-plan floor plate and allow for a high ratio of windows within the facade, thus reducing the structural zone available in the facade. Initial discussions signalled two materials that would be acceptable

gained by using di ff erent erent sized columns.  The experience gained at Clerkenwell Close has aided our general understanding of the design and construction of medium-rise loadbearing stone buildings and has contributed greatly to our development of a standardised stone building system. For example, a key consideration in the design of this building was to avoid cold bridging between the floor slabs and facade columns (Figure 5). 5). We have since designed a mixed-use 10-storey loadbearing stone building at 317 Finchley Road, London (Figure 6). 6). Working closely with Groupwork + Amin  Taha,  T aha, we have further developed the design and detailing using the lessons learned from Clerkenwell Close. This project is currently under construction and is expected to be completed during 2021.

WE PROPOSE A BUILDING SYSTEM THA THAT T WOULD BE BE A LOW-ENERGY  ALTERNA  AL TERNATIVE TIVE TO STEEL AND CONCRETE-FRAMED STRUCTURES

   N    A    E    L    C    A    M    N    H    O    J  

êFIGURE 3: Concept

sketch for stone building system

ìFIGURE 4: Straight

post-tensioned stair before balustrade installation

29

thestructuralengineer.org thestructuralengineer .org | October 2020

   

Technical

Stone as a structural material

IT IS NORMAL PRACTICE IN THE UK TO CONSIDER RESTRAINT AND LOAD-INDUCED CRACKING INDEPENDENTLY 

   O    T    I    V    N    A    S    S    E    N    G    A

ìFIGURE 4: Loadbearing stone facade at

Clerkenwell Close

has beenofestimated that, tstone hrough theIt adoption a loadbearing facade, an approx. 18% reduction in cost has been achieved. By combining this with cross-laminated ti mber (CLT) floor slabs in some areas, a signi ficant reduction in embodied carbon and energy over conventional construction methods has also been achieved.

Beams  As mentioned earlier, the use of

ratio (Figure 7). 7).

reinforcement and/or post-tensioning within the column elements may be necessary or desirable. Our approach to reinforced and post-tensioned stone elements is explored in greater detail in previous articles4,5 in this mini-series, with these methods of design and analysis allowing for stone beams with a fairly high span-to-depth

Slabs Unlike vaulted stone structures which ensure the stone is working only in compression, or post-tensioned stone which utilises steel tendons to work in tension in concert with stone in compression, the reciprocal stone tile floor is perfectly level but includes no steel reinforcement.

6:  Niamet, solor am voluptati quam qui dolorup ientotatia cupitis îFIGURE

6:  Niamet, solor am voluptati quam qui dolorup ientotatia cupitis îFIGURE

ìFIGURE

5: Facade beam/ 

column connection sketch

30

30 October 2020 | thestructuralengineer.org

 

Stone as a structural material

   Y    N    A    P    M    O    C    Y    R    N    O    S    A    M    E    N    O    T    S    E    H    T  

éFIGURE 7: Post-tensioned stone beam

demonstration piece

It is common for structural engineers to be commissioned to inspect and specify repairs to Victorian and Georgian stone staircases and landings. From these inspections, it is often apparent that quite large, yet comparatively thin landing slabs were used. On closer inspection, the landings can be seen to be built from much smaller stones configured, in eff ect, ect, as a horizontal run of stair flight (Figure 8). 8). From these historical precedents, it is a small leap to imagine that a floor could be built in this way. In a similar manner, manner, a child’s tile puzzlesegments formed with tongue-in-groove hasplastic no rails to support the tiles (Figure 9). 9). The tiles transmit torsion to the edges through their edge joints. As a tensegrity structure can be referred to as ‘discontinuous compression’, so this configuration could be described as ‘discontinuous bending’. We began to see that an extensive stone floor could be built in this way.  The advantages being that a large floor could be quickly built manually from small (easily winnable) stone slabs.  Analysis suggested that stone working    Kin this way could be thinner than its    R    O    Wequivalent in concrete and very ‘low    P    Ucarbon’ (Figure 10). 10).    O

   R    G    The configuration of this reciprocal floor system would be highly redundant. éFIGURE 6: Illustrated

view of 317 Finchley Road

ìFIGURE 8: New-build

reciprocal stone stair landing

Technical

Engineers normally approach redundancy from the perspective of ductility, but in this case the stone is clearly anything but ductile. The advantage of this configuration is that there are many load paths. Many individual plates have to fail before a total collapse occurs.

Live demonstration

In August 2016, Webb Yates was invited to devise an exhibit at the  Victoria and Albert Museum (V&A) in London. Together with The Stonemasonry Company, we decided to take the plunge and live-build a prototype, both as a demonstration and as an experiment.  The design was very simple: a 3m × 3m plate formed with 36No. 500mm square flag stones supported around the perimeter only. To build these quickly, we formed the corner joint by clipping the very thin stone tiles together at their corners and holding the structure along all four sides (Figures 11 and 12). 12) .  This 3m span in stone is 40mm thick; the would same span in reinforced concrete be perhaps 100mm thick. A 7m span in stone would be approx. 125mm thick; the same span in reinforced concrete would be in the order of 250mm thick 6. Compared with reinforced concrete, the stone tile floor contains less than half the embodied energy and less than a quarter of the embodied carbon2.  The stone tile floor is therefore an example of a geometrically simple, elegant structure that is nevertheless innovative and environmentally ethical.

Exoskeleton  A stone stone exoske exoskeleto leton n has has several several advantages. A curtain wall set back approx. 200mm ensures both

31 thestructuralengineer.org thestructuralengineer .org | October 2020

   

Technical

Cracking Stone as of a structural concrete material

   K    C    O    T    S    I 

ìFIGURE 9: Child’s tile puzzle

éFIGURE 10: Finite-

element analysis output – principal stresses

weathering and thermal performance remain high without the need for window interfaces and with fewer thermal bridging points. In turn, this results in a high-performance envelope that is lower in cost.  Additionally, separating the stone structure in this way reduces the impact of a fire event by reducing direct exposure and limiting induced stresses. Embedding the structure within the facade would expose one or two surfaces to full fire temperatures, producing diff erential erential temperatures across the column section and leading to additional secondary stresses and material spalling or delamination. This would require an increased section size or additional fire protective finishes. The exoskeleton approach has been validated through testing at the BRE.  Through careful architectural design, the exoskeleton can also be used as solar shading to minimise summer heat gains and reduce cooling loads.

Solid-stone building ‘system’: proof of concept

   N    O    S    N    E    H    P    E    T    S      M    I    J  

ëFIGURE 11: Torsional floor plate

for V&A under construction

íFIGURE 12: 

Completed torsional floor plate for V&A 

In 2017, Webb Yates askedfor toabuild a demonstration of itswas proposal building system for the ‘Super Material’ exhibition at The Building Centre in central London (Figure 13). 13). In this case, we looked to refine the torsional stone slab floor concept, and incorporated a new cruciform joint to link the stone panels. We built three columns, two beams and quarter of a plate to save money and space (in this case, the system has no redundancy). Due to a specific error in the design of one of the corner plates, the system failed and had to be rebuilt, and our quest for greater understanding continues.  This failure does highlight the need for redundancy when building with brittle materials. Our approach to date has been to ensure multiple load paths are always present, and where appropriate to use the notional removal approach in combination with horizontal and vertical ties to ensure robustness1. More recently, Webb Yates was invited to co-curate an exhibition entitled ‘The New Stone Age’, again at The Building Centre. As part of the exhibition, we undertook a further

Box 1. Team for New Stone Age research project    N    O    S    N    E    H    P    E    T    S      M    I    J  

Structural engineer: Webb engineer: Webb Yates Engineers  Groupwork   Architect:  Archite ct: Groupwork  Cost consultant: Jackson consultant: Jackson Coles Sustainability: Eight Associates Construction methodology: The methodology: The Stonemasonry Company Supplier: Polycor Supplier:  Polycor

32 October 2020 | thestructuralengineer.org

  

Stone as a structural material

HAVE  YOUR  YO UR SAY  SA Y 

Technical

overall carbon and cost saving for the stone typologies (Table 1 and Figure 15).. 15)

Conclusions íFIGURE

17: 

Typical stair connection details

[email protected]

13: Solid stone building system demonstrated as part of ‘Super Material’ exhibition ëìFIGURE

îFIGURE 14: Notional

30-storey offi ce tower   

@IStructE

research project in collaboration with a team of other consultants (Box 1) to 1) to explore the viability, comparative cost, programme and embodied CO2 for a notional commercial offi ce tower of 30 storeys (Figure 14). 14).  The brief was developed by some of the UK’s leading developers to optimise the ideal column-free floor spans with internal flexibility for speculative offi ce leased spaces.  The project intended to investigate whether large-scale commercial buildings can be The built proposals with stonewere superstructures. required to deliver the same criteria of optimum offi ce space and building height as steel and concrete structures, while simultaneously achieving the same or lower construction cost and carbon footprint. Granite or basalt were proposed for their ability to withstand high temperatures and retain structural integrity in the event of a fire, in addition to their availability, cost-eff ectiveness, ectiveness, aesthetic and textural qualities.  The findings of this study revealed an

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#TheStructuralEngineer

In summary, we believe the use of stone could be quicker, cheaper and lower the embodied energy of a building’s materials and its construction. A solid-stone framing system is an example of a geometrically simple, elegant structure that is nevertheless innovative and environmentally ethical.  The system off ers ers several key benefits: | It gives the opportunity for signi ficant reductions in a building’s embodied carbon. | The  The overall weight of the building fabric can be reduced, thus reducing the total loads onto the foundations.  There is a reduction of loads on the | There floor perimeter, reducing the need for edge beams and allowing clean soffi t lines. | The  The interface between architectural and structural elements can be simpli fied and more easily coordinated. 

| There  There is a reduction or elimination of

secondary framing elements required to support cladding or other finishes. | Bringing the architect into the structural domain leads to greater collaboration and sharing of knowledge.

REFERENCES 15:  Embodied carbon comparison of different construction typologies for 30-storey offi ce tower  íFIGURE

1) British Standards Institution (2002) BS EN 1990:2002+A1:2005 Eurocode. Basis of structural design,

London: BSI 2) Circular Ecology (2019) Inventory of Carbon and Energy , V.3.0 [Online]

 Available  Availabl e at: http https://c s://circ ircular ularecol ecology ogy.. com/embodied-carbon-footprintdatabase.htmll (Accessed: database.htm September 2020) 3) Dickson M.G.T. and Werran G.R. (1999) ‘The post-tensioned,

prestressed Ketton stone perimeter prestressed frame of The Queen’s Building, Emmanuel College, Cambridge’, The Structural Engineer , 77 (20), pp. 19–29 4) Boote S. (2020) ‘Stone as a

structural material. Part 2: Traditional and reinforced stone stairs’, The Structural Engineer , 98 (6), pp. 18–28

Cost

TABLE 1: Cost comparison of different construction typologies

5) Boote S. and Lynes A. (2020)  

for 30-storey offi ce tower

‘Stone as a structural material. Part 3: Post-tensioned stone structures’, The Structural Engineer , 98 (8), pp.

Stone exoskeleton + stone cores + stone floors

Stone exoskeleton + CLT cores + CLT floors

Steel frame + concrete cores + composite steelconcrete deck floors

Concrete ‘flat-slab’ frame + concrete cores

£2902/m2

£2790/m2

£2984/m2

£3015/m2

22–28 6) The Concrete Centre (2019)  Economic Concrete Frame Elements to EC2, London: The Concrete

Centre

33 thestructuralengineer.org thestructuralengineer .org | October 2020

Opinion

Profile

 

Sinéad Conneely and Laura Hannigan Four thirty-somethings are just over one year into life as the Simple Works structural practice. Jackie Whitelaw talked to two of the founders, Sinéad Conneely  and  and Laura Hannigan, Hannigan, about branching out on their own, and shaping the future.

Sinéad Conneely, 32

Laura Hannigan, 32

Education: BEng in civil

Education: MEng in structural

engineering at National University of Ireland, Galway and MSc in applied mathematics at Imperial

engineering with architecture at University College Dublin and MSt in interdisciplinary design for the built environment at

College, London. Current role: Co-founder of Simple Works.

University of Cambridge. Current role: Co-founder of Simple Works.

Previous employer: AKT II.

Previous employers:

Other roles: Co-founder

 Thornton Tomasetti and AK T II.

of Scale Rule, tutor to disadvantaged and marginalised young people, technical tutor for the  Architectur al Associ ation, London.

Other roles: Senior teaching

WELL BEFORE COVID-19 turned

established practice on its head, Laura Hannigan was part of a team that won a competition to envisage the o ffi ce of 2035. Much of the industry is currently debating just how offi ces will look after the pandemic, but Hannigan and her peers had an answer back in 2017 – even if no one was expecting to need their solution quite so soon. ‘It turns out we were predicting not only offi ce life after Covid-19, but also what its potential impact might be on university operation,’ Hannigan says. ‘We envisaged a large dropoff  in   in numbers of students needing accommodation as teaching moved online, and turned a block of Georgian housing that had been student rooms into a central creative offi ce hub (Figure 1). We anticipated that people wouldn’t be coming to the o ffi ce every day, just travelling in occasionally

fellow in structural design practice at the Bartlett School of Architecture, London. Cofounder of community interest company Scale Rule, which seeks to promote diversity and engagement in the built environment.

because technology would allow them to work rem otely. otely.’’  At Simple Works, the cr ystal ball has come out again, this time with cofounders Sinéad Conneely, Phil Isaac and Jonny Hawkshaw, to create the vision for their new business. This is founded on a conviction that it is young professionals who will be the source of solutions to deal now with climate, social change and, who knows, more pandemics. ‘Construction needs to pivot quickly to respond to whatever the future throws our way, as do clients. For us, climate and community are top of the list. It will be up to younger people like us to reposition our industry and to come up with broader ideas,’ Conneely says. ‘If the needs of society and a response to climate change are to be met over the next 20 years, we are going to need new thinking.’

Seeking autonomy  Simple Works’ aim is to be a business that designs schemes that local people want to live in and with, rather than buildings that are alien and imposed on them. ‘Our role is to be a company that does good and is answerable to our communities,’ Conneely explains, ‘with sustainability at the heart’. ‘That mission is so important to all of us. It was a natural progression to want to go out there and do it for ourselves through our own business,’ Hannigan says.  The four founder s all quickl y became friends while working for AKT II. ‘I really liked it there and we were all working on big, complex, amazing projects,’ Hannigan says. For Hannigan, these included the substructure for Facebook’s One Rathbone Square development and the exposed steelwork at Google’s new King’s Cross, London HQ. Conneely was writing bespoke software scripts to streamline her work and was part of  AKT’s parametri c team on Heatherw ick Studio’s Al Fayah Park in Abu Dhabi. ‘But we realised that we wouldn’t have autonomy or control over the big design decisions for years. And we wanted to choose our projects and make those decisions now,’ Conneely says. ‘We worked it out and realised that we were likely to be in our fifties before we had that complete selfdetermination if we stayed in a big practice.’  That seemed too lo ng a wait when the threats and issues they were concerned about felt immediate. ‘We were lucky to have found each other, to have found four like minds and to have developed the trust that gave us the confidence to go out on our own.’  The busine ss launched o ffi cially in May 2019, with all four initially sat round

IT WILL BE UP TO YOUNGER PEOPLE LIKE US TO REPOSITION OUR INDUSTRY  AND TO COME UP WITH BROADER IDEAS

34 October 2020 | thestructuralengineer.org

 

Profile

íFIGURE 1: Winning

‘Offi ce of 2035’ proposal by Team 88mph for BCO NextGen design competition (2017). Georgian terrace is repurposed as creative offi ce hub in London, to suit commuters and small teams

êFIGURE 2: 

Findhorn Foundation development, Scotland

one kitchen table. Within six weeks, they realised they needed some offi ce space and moved into a converted shipping container. One boiling summer and a freezing winter later, they are now in a more conventional offi ce on the same site. ‘It was amazing, we built some of our own furniture, bought chairs on Gumtree, but we are glad to have moved everything into our o ffi ce here in Hackney,’ Hannigan says.  

Carbon goals Despite the pandemic, they are doing very well and are ready to employ a new engineer. ‘We are really busy, but when we started we lacked the confidence to charge industry standard fees, our prices were too low. We had clients calling sometimes to tell us to up the fee’, Hannigan says of the pitfalls of starting a new business. ‘One of the biggest issues at the beginning was to admit to each other how much of a financial cushion they each had. ‘We had to understand how long we could each go on while waiting to be paid – that turned out to be six months plus back-up plans. We have now got to the point where the fees are

Opinion

right and all along we have managed to pay ourselves something every month,’ Hannigan says.  They don’t have the luxur y of turning away work that doesn’t quite fit their vision, but ‘we have become very good at translating community demands to clients and architects, so we can make better decisions for buildings. And we can convince them that investing 5% extra upfront can deliver 20% carbon reductions that will become increasingly important in the long-term value of their structures,’ Hannigan says. Current projects include a co-housing development of 25 units in Norfolk, an eco village in Moray in Scotland for a spiritual community (Figure 2), 2), and the refurbishment of a carriage works in Swindon (Figure Swindon  (Figure 3). 3). Carbon reduction is at the root of their designs. ‘In Moray, for instance, our client has agreed to allow the walls to be thicker so we can use recycled insulation, the superstructure is all timber and we are installing steel screw piles for the foundations instead of using concrete,’ she says. Where possible, they are focused on avoiding demolition and reusing existing structure in pursuit of carbon effi ciency. ‘I’d like to see the country get to a position where buildings are not only listed architecturally but structurally, so those that are still sound for a given loading can’t be demolished,’ Hannigan says.

35 thestructuralengineer.org | October 2020

 

Opinion

Profile

Embracing diversity 

Sharing knowledge  The Simple Wor ks team set out to find likeminded clients from day one. ‘We started with friends, then friends of friends, who were mainly architects. Level three was some cold calling and networking events. We made lists, decided who we wanted to work with and targeted them. ‘And at the London Festival of  Architectur e, we were out every night meeting new people and it paid o ff . We found that by being really honest about ourselves and our vision, we got a response and made a connection with people who think like us.’  That openness opennes s is a key part of the Simple Works culture, Conneely explains. ‘We are all about transparency and being open to other practices and to new ideas and materials. We think that if structural engineering practices are of a high standard, that’s good for everyone, so want to share knowledge and experience. We are all in the same industry and want to be friends with our peers. It’s good for the profession if we are all at our best.’

THE FUTURE OF THE PROFESSION RELIES ON DIVERSITY AND EQUALITY, SO WE CAN RELATE TO THE COMMUNITIES WE WORK FOR

3: Swindon Carriage Works with masonry jack arches and cast iron columns ìFIGURE

4: Diversity of thinking is at core of Simple Works’ philosophy îFIGURE

 To that end, Simple Works is part of the Small Practice Forum, which is a place to exchange knowledge and to understand the challenges that are common to all the members. They also organise the Sekforde Sessions (https://  sekfordesessions.com) – sekfordesessions.com)  – a series of ‘provocative debates on the state of the structural engineering profession’.  

Conneely and Hannigan are also members of the Female Founders Forum – a group of women structural engineers who have set up their own companies and which acts as a sounding board and support group. It’s nice to have that back-up, they say.   At the forum, they have all had the common experiences of sexism, such as being dragged along to meetings on projects they are not part of to boost the diversity, or being spoken over at meetings. ‘But it reminds us to also be aware of the unconscious bias issue, that people like hanging out with and promoting people that are like them’, Hannigan says. ‘As Simple Works grows, we know to be aware of that when we go out and recruit. We all have unconscious bias, but realise that a team of people that are all the same is not good for problem-solving.’ Conneely adds: ‘There have been a lot of studies on the e ff ectiveness ectiveness of diversity of teams. The four of us are really diff erent erent (Figure 4) and 4) and we know we come to better solutions because we question each other more, and that makes us less likely to think our own opinion is the only one or the right one. ‘We like that healthy debate and we want our team to look very di ff erent erent to us as it grows. ‘Diversity will only benefit the profession. We love what we do, but the future of the profession relies on diversity and equality, so we can relate to the communities we work for, and truly arrive at the best solutions in our day-to-day problem-solving and for the profession as a whole.’

If you’d like to find out more about either the Small Practice Forum or Female Founders Forum, email hello@simple-works. co.uk.

HAVE  YOUR  YOUR SAY  SA Y 

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36 October 2020 | thestructuralengineer.org

 

Opinion

Planning application procedur procedures es

Lessons from the box-girder failures

Opinion

 

 Viewpoint

The box-girder failures 50  years  yea rs on – les lestt we for forge gett Ian Firth looks back at the box-girder bridge collapses of 1970 and considers the applicability of the lessons learned to structural engineers today.

THE STORY OF HUMAN ENDEAVOUR is one of constantly learning

in various stages of construction and a further 30 in the design stage. The technology had developed rapidly during the 1960s, not least with the completion of the Severn Bridge in    A    I    R1966, and many designers were excited about    O    Tthe possibilities aff orded orded by steel box girders    C    I    V and thin-plate structures. Hence, the terms of    E    C    I reference for the Merrison Committee included    F    F    O‘to consider whether the collapse of the    D    RMilford Haven and Yarra Bridges necessitates    O    C  reconsid nsiderati eration on of of the the design design and method method of    E reco    R erection for any major box girder bridges about    C    I

from experience, and history is littered with examples of how mankind had to learn the hard way from mistakes. Sometimes the mistakes and lessons occur over many decades or even centuries, such as those surrounding the climate crisis, but at other times they happen very suddenly.  These  Thes e lessons lessons ofte often n involve involve grea greatt cost, cost, even great loss of life, and for those involved the experience can be extremely painful. But at least they will never forget those hard lessons. For them, the memory is still too raw, and it will influence their decisions and activities for the rest of their lives. However, others are forced to read their stories – to learn from the history rather than the experience – and it is possible to read stories in a detached way that misses their significance, or to miss the stories altogether. This is why history is so often destined to repeat itself.  Young  Y ounger er genera generations tions risk dism dismissin issing g the stories as interesting but irrelevant or inapplicable. Things were diff erent erent then. Things are better now. We don't make those kinds of mistakes anymore. Or do we?

Tragedy  Fifty years ago, on 15 October 1970, the West Gate Bridge across the Yarra River in Melbourne,  Australia, colla  Australia, collapsed psed durin during g constru constructio ction, n, killing 35 people (Figure 1). 1). It remains one of  Australia’  Austr alia’s – indee indeed d the const constructi ruction on indust industry’ ry’s s – worst accidents. Just four months earlier, on 2 June, in Milford Haven, South Wales, another steel box-girder structure, the Cleddau Bridge, had collapsed during construction, killing four people (Figure 2). 2). Two steel box-girder bridges collapsed in just a few months. We should take a moment on this poignant anniversary to consider those tragic events and remember those who suff ered, ered, and still suff er, er, as a result.  All of a sudd sudden, en, there there was an urgent urgent need need for answers and an awful lot of lessons to be learned. What followed was one of the most intense periods of lesson learning in bridge design and construction history, history, made possible due to the extraordinary volume of work undertaken by pre-eminent engineers working at the cutting edge of emerging bridge technology at the time.

   L

   Bto be erected in the UK’.    U    P  Assessment  Asses sments s were were carrie carried d out out on 51 bridg bridges es    ©    Ealready in service and 37 not yet in service at    G    Dthe time: 19 of the 51 in service were found to    I    R    Bbe completely inadequate and the remaining 32    E    T    Aneeded strengthening; while 28 of the 37 not yet    G    Tin service were found to need strengthening. In    S    E other words, 90% were found to be inadequate!    W  

1: West Gate Bridge following collapse during construction in October 1970 ìFIGURE

One of those engineers was Dr Tony Tony Flint, a Gold Medallist of the Institution of Structural Engineers, who I am privileged to have worked with for much of my professio professional nal life. Alongside Professor Michael Horne (another Gold Medallist) and others, he was a key member of the Merrison Committee of Inquiry set up to investigate and advise on the design and method of erection of such structures.  The Commit Committee tee prod produced uced an interim interim repo report rt as early as June 1971 and its final report in February 19731, complete with radically new design and workmanship rules in four parts, the so-called Interim Design and Workmanship Rules (IDWR).  At the the same same time, time, in Austral Australia, ia, investigat nvestigations ions were ongoing which led to the publication in 1971 of the Royal Commission’s report into the failure of West Gate Bridge2.  These two docu documents ments rema remain in essenti essential al reading for every practising bridge engineer today.. In fact, they spotlight an essential lesson today that everyone needs to learn, not just bridge engineers, and most especially our clients.

Urgency   The need need for answe answers rs was was extre extremely mely urgen urgent. t. In In the UK alone, there were 49 steel box girders

No wonder there was an urgency for new design rules. Not long afterwards, in November 1971, yet another steel box girder collapsed, this time across the Rhine near Koblenz in Germany Germany,, killing 12 people. The urgency was acute.  As Dr Flint said in his Gold Gold Medal Medal addr address ess3, there was not enough time to be brief!  The desig design n code code at the time, time, BS 153, 153, was inadequate, and did not cover these structures. Designers were applying codes beyond the scope for which they were intended without adequate research to back up the application.  The Commi Committee ttee colla collabora borated ted with rese research archers ers from several organisations and an extensive programme of work was undertaken in double-quick time to derive new design and workmanship rules – the IDWR. These were extensive and exhaustive, and although complex to apply, they allowed a proper prediction of thin steel plate and box girder behaviour for the first time.  These were extr extraord aordinary inary times times.. It was the early days of limit state design, and the weaknesses of the old working stress methods were becoming clear. clear. The need to assign partial safety factors to diff erent erent aspects of the design depending on the uncertainties associated with each aspect was now understood. It seems obvious with the benefit of hindsight and our modern methods of working, but at the time this was revolutionary.

37 thestructuralengineer.org | October 2020

   

Opinion

Lessons from the box-girder failures

READ THE REPORTS Improved procedures By and large, the technical lessons have been learned, and the proper application of modern design codes should now deal with the behaviour adequately. adequately. But I feel compelled to draw attention, once again, to the vital procedural lessons that were learned and the improvements that were implemented, hopefully to avoid recurrence. This is where the generational amnesia I alluded to earlier seems to be happening, and critical lessons are in danger of being forgotten. Even worse, they may have been learned lear ned but are being ignored. Bridge collapses, or near failures, still occur far too regularly, most commonly during construction. The footbridge at Florida International University in 2018 is a case in point (Figure 3). 3). Usually there is a technical error involved – something breaks – and these need to be understood and repetitions avoided. But in every case, it is the procedural background, background, the commercial, contractual and human processes preceding the collapse, that hold the clues as to why the disaster was not averted.  As Sir Sir Alec ec Merriso Merrison n said in pre presenti senting ng the Committee’s conclusions in 1973: ‘No  amountt of writ  amoun writing ing of of design design code codes s and writ writing ing of contracts can in the end be guaranteed to  prevent  prev ent the result results s of stup stupidity idity, carelessn carelessness ess or  incompeten  incom petence. ce. But one one can do a grea greatt deal deal to discourage these vices and that must be done.’ So, for example, in concluding that ‘the diaphragm (on Cleddau Bridge) as designed simply was not strong enough to resist the severe compressive forces it was subjected to during erection’, the erection’, the Committee’s recommendation was to strengthen the procedural requirement for checking bridge designs during erection. As any competent bridge engineer should know, design for erection is a critical part of the designer's job, or it should be.  Already  Alre ady in its its interim interim repo report, rt, the Merris Merrison on Committee made a strong recommendation recommendation for full and independent design checking.  The Commi Committee ttee cons consider idered ed it essen essential tial that the ‘Engineer’ ‘Engineer’s s permanent design should be checked by an independent engineer who will  issue a certi  certi fi  c ect that the design, ficate   ate to the eff ect  modi fi ed ed if necessary, will comply with the  general  gener al criteri criteria we have laid down in Appendi Appendix  A’’ (these were the new draft design rules) and  A furthermore that ‘a check should similarly be  made that the stres stresses ses in the struc structure ture during ng erection also comply with the criteria.’  The Comm Committee ittee’’s report reports s led dire directly ctly to the the introduction of mandatory independent design checking and to improvements in the standard Conditions of Contract in use at the time. Indeed, the recommendations were considered of suffi cient importance to warrant immediate implementation by the government of the day.  The independen ndependentt checking checking syste system m familiar familiar to

The Report of the Royal Commission  into the Failure of West West Gate Bridge is available online from the Parliament of  Victoria at www.parliament.vic.gov.au/  papers/govpub/VPARL1971-72No2.pdf.

SCAN QR CODE The Merrison Report, Inquiry into the  basis of design and method of erection erection of steel box-girder bridges, is available at www.istructe.org/resources/blog/  learning-from-history-box-girderbridges/ .

SCAN QR CODE

UK bridge engineers today was instituted at this time. Four key procedures were recommended by the Committee and accepted by the government as being indispensable: | an independent check of the Engineer’s permanent design | an independent check of the Contractor’s method of erection and temporary works design | clear allocation of responsibility between the Engineer and the Contractor (this coming largely from the confusion that contributed to the West Gate collapse) | provision by both the Engineer and the

Contractor of suffi cient adequately qualified supervisory staff  on  on site.   Unfortunately,, these procedures have Unfortunately softened over the intervening years in some circles. There are several contributory factors, including changes to contractual arrangements, fragmentation and blurring of responsibilities, increased use of design-and-build contracts, and the diminishing role of the engineer engineer..  At the the time, me, const constructi ruction on was was genera generally lly via via the the ICE Conditions of Contract, which required the Contractor to provide the Engineer with such particulars of their arrangement for executing the works as the Engineer deemed necessary, necessary, without of course relieving the Contractor of their responsibility. Furthermore, there was a general assumption that there would be a Resident Engineer on site with suffi cient suitably experienced staff   to supervise the works. This was common practice. Even so, the Committee saw fit to recommend a strengthening of the Engineer’s role in respect of checking the Contractor’s Contractor’s proposals. How diff erent erent things are today! The engineer’s role has been significantly eroded, and the designer is rarely resident or even represented on site.  The standa standard rd Cond Conditio itions ns of of Contrac Contractt also also required the Contractor to satisfy the Engineer regarding the ‘suffi  ciency of the quali fi  c fications   ations  and exper experience ience of the the Contrac Contractor’ tor’s site site staff    and the adequa adequacy cy of their numbe number’ r’ and the Committee went on to recommend that this should be rigidly enforced. How often do contracts require that today?  

 Anniver  Anni versar sary y wake wake-up -up cal calll  The conclusions usions drawn drawn back then are still relevant today, today, and they apply to a much wider

2:  Cleddau Bridge following collapse during construction in June 1970 íFIGURE

38 October 2020 | thestructuralengineer.org

   

Opinion

Lessons from the box-girder failures

context than merely that of steel box-gird box-girder er bridges. Take, for example, this impassioned statement, made after describing the large number of bridges in the UK found to be defective and requiring strengthening: ‘We would suggest that an error which may  have led to to many many of the desig design n defects defects foun found d in the British bridges is the excessively mechanical use of Codes of Practice which, even if they  are dire directly ctly applicabl icable to the struct structures ures being designed, are unlikely to result in a satisfactory design in the hands of a designer lacking the experience to appreciate and allow for the  peculiarities iarities which which each indiv individual idual struc structure ture  invariably  invar iably exhib exhibits.’ its.’  This applies ies widely widely,, and simple adherenc adherence e to design rules should on no account be regarded as a substitute for sound engineering judgement and relevant experience. Enlightened clients with major complex building projects, such as stadia or large airport terminals, do occasionally appoint an independent checking engineer, but there

Lessons from the box-girder failures

3: Pedestrian bridge at Florida International University following collapse during construction in March 2018 ìFIGURE

   Y    M    A    L    A  

NO AMOUNT OF WRITING OF DESIGN CODES AND WRITING OF CONTRACTS

is a strong case that this practice should be extended further. Normal building control checks tend to be insuffi cient in cases involving non-standard or complex structural applications. Similarly, Similarly, the more complex the structure, the more vital the need for designer representation on site. We certainly need to adhere to the recommended procedures procedures which are there for good reason, but even more importantly we need to ensure the competence of those applying them. This is why the work of the Institution in the area of ensuring en suring the competence of its members is so vital.  The Instit Institution ution is closely osely involved ved with the developments in this area arising out of the Grenfell Tower disaster and the UK’s new draft Building Safety Bill.

construction or even know what kind of competence they require, which is partly why our Code of Conduct requires us to selfregulate and only take on work for which we are genuinely competent. Life moves on and things change, but the principles of care and attention, qualification and competence, responsibility and communication

I sometimes encounter clients and others responsible for appointing consulting engineers who know nothing about this history or the significance of these lessons. Many would not appreciate the importance of ensuring that designers are closely involved during

remain unchanged. It is these that matter most, and the lessons learned 50 years ago are every bit as relevant today as they were then.  Anniversarie  Annive rsaries s provid provide e an oppor opportunit tunityy to look back and remember. Anniversaries of tragedies demand that we look back and ask if the

CAN IN THE END BE GUARANTEED TO , PREVENT THE RES RESUL ULTS TS OF STUPIDITY STUPIDITY, CARELESSNESS OR INCOMPETENC INCOMPETENCE. E. BUT ONE CAN DO A GREAT DEAL TO DISCOURAGE THESE VICES AND THAT MUST BE DONE SIR ALEC MERRISON, 1973

KEY LESSONS

| Think beyond standards and codes

in your design. Simple adherence to design rules should not be regarded as a substitute for sound engineering judgement and relevant experience. | Always consider the forces arising during erection in any design, and if necessary insist on an independent check of the erection process. | Get your design checked. The level of check will depend on the nature of the structure. In bridges the categories are defined, with the highest level requiring fully independent checking and certification by an external organisation, but similar procedures can be applied to complex or large public buildings. ensure provision by the contractor of su ffi cient adequately quali fied supervisory staff on site. | Persuade the commissioning client to ensure that the designer’s team is resident on site during construction. | Instigate a process to

Opinion

lessons have been learned. I am concerned that they have been forgotten in some circles and there is a real danger of a tragic history repeating itself.

Ian Firth BSc, MSc, DIC, CEng, FREng, FIStructE, FICE

Ian is an acclaimed bridge engineer and Consultant for COWI. He served as President of the Institution of Structural Engineers in 2017.

REFERENCES

1) Royal Commission of Inquiry (1971) Report of Royal Commission into the Failure of West Gate Bridge, Melbourne: Government of

 Victoria [Onlin  Victoria [Online] e] Availab Available le at: at: www.parl www.parliament iament.. vic.gov.au/papers/govpub/VPARL1971-72No2. pdf (Accessed: September 2020) 2) Merrison Committee (1973) Inquiry into the basis of design and method of erection of  steel-box  steel-bo x girde girderr bridge bridges s, London: HMSO 3) Flint A.R. (1989) ‘Gold Medal address: Matters of balance’, The Structural Engineer,

67 (10), pp. 189–191

39 thestructuralengineer.org | October 2020

 

Opinion Opinion

Planning Engineering application in Jamaica procedures procedur es

 

 Viewpoint

Structural engineering – a view from Jamaica

 Alfric  Alfr ico o Ada Adams ms,, a Fellow of the Institution of Structural Engineers, looks back at over 60 years of structural engineering in Jamaica and the Caribbean, and the development of local educational and professional bodies in the region.

Personal experiences In 1959, as a 20-year 20-year-old -old with some experience as a structural engineering technician, I travelled from Jamaica, then a British colony, colony, to England, to seek a career in structural engineering.  Although  Alth ough the Unive University rsity College lege of the the West West Indies (now University of the West Indies) off ered ered engineering studies, it was then located in  Trinid  T rinidad, ad, a nearby nearby Caribbean bbean island, and, and did not provide the opportunity for work and study. The Jamaica College of Arts, Science and Technology (now University of Technology, Jamaica) did not yet enjoy degree-g degree-granting ranting status. During five to six years of study at Hammersmith College, London, I focused on the curriculum of the Institution of Structural Engineers (IStructE) , including the Graduateship and Final, Parts A and B stages, which eventually led to Corporate Membership of the IStructE in 1965 and the status of Chartered Engineer in 1968. My first impression of the UK was good thanks to my preparations before leaving Jamaica. I lived with a Jamaican migrant family and had Jamaican neighbours, so apart from the shock of the weather, things went well.  Also,, having  Also having been refe referred rred to a Lond London on firm for immediate employment, I was spared the task of job-hunting and able to interact with professionals professio nals in an engineering design offi ce environment in that early stage after arrival. I had good relationships in both work and study, and soon identified a small circle of Jamaicans in London who were engaged with the same objectives as I was. I returned to Jamaica in 1965 and, except for a couple of years back in the UK for further study and advancement, my full career of over 50 years has been pursued in Jamaica and the Caribbean. By 1969, I had set up a private consulting engineering practice, A.D. Adams & Associates. In the mid-1970s, after a few years of collaboration collaboratio n with other firms, this was registered as SMADA Consultants Ltd. On the professional side, in 1984, I became President – and later Fellow – of the local Institution of Engineers. Later still, in 1997, I was elected a Fellow of the IStructE.

CAREER HIGHLIGHTS Our portfolio of work at SMADA Consultants Ltd has covered a wide range, from offi ce and commercial developments to residential developments, institutional buildings, dock structures and industrial facilities: | 1970s

– Assoc  Associate iate Structura Structurall Consultant Consultant on on the design design of a 13-storey 13-storey buildi building. ng.

| 1980s

and 1990s – collaboration with Jamaican and Caribbean engineers in an

effort to produce the Jamaican National Building Code and Caribbean Uniform Building Code. | 1990s

and 2000s – design of 3000m of dock with 13–15m draught for the Port of

Kingston. | 2000

onwards – design review and check consultancy for a range of structures, including a Kingston landmark, Half-Way Tree Transportation Centre. The original design of this facility was by Euro Immo Star, a Belgian firm, but responsibility for design review and supervision was passed to SMADA by the Port Authority on behalf of the government.

40 October 2020 | thestructuralengineer.org

Engineering in Jamaica

 

Engineering in Jamaica and the Caribbean  As far far back back as the time time of of my retu return rn to Jamaic Jamaica a from the UK 55 years ago, it was evident that the extreme natural disasters, such as earthquakes and hurricanes, which occurred in Jamaica were not characteristic of the UK, and that engineers trained in the UK needed to broaden their horizons to include these phenomena on returning to the Caribbean. The experience of states in the USA, such as California for earthquakes and Florida for hurricanes, proved to be important. I took a particular interest in this on my return and by the early 1980s had become active in the field of continuing professio professional nal development (CPD) for the profession in Jamaica and the Caribbean. In the meantime, in 1966, local engineers formed the Institution of Engineers, Jamaica (IEJ), modelled on the chartered institutions in the UK, and used this organisational structure to provide a base for disseminating disaster-resistant disaster-resistant technologies to our then mostly British-trained engineers.  The gro growth wth of first the Engineering Faculty of the University of the West Indies, and later the University of Technology, Jamaica, provided

which supplemented our available guides and procedures.  As time time went went by by, it becam became e evident evident that our limited resources in the Caribbean could not sustain the rapid upgrades required in this eff ort. ort. A significant shift was made to rely on compatible foreign codes as base-codes and to study and codify the local phenomena for use with these codes.  The late ate 1970 1970s s saw a reform reformulatio ulation n of the IEJ to the Jamaica Institution of Engineers (JIE), followed in the 1980s by the formation of a statutory Professional Engineers Registration Board. This Board is now the legal body assigned to register professional status, while the professional professio nal institutions are expected to focus mainly on learned-society activities and CPD. In this new environment, the IStructE is seen as a UK-based qualifying body which supports the technical and professional development of structural engineering.  Apart fro from m these these technic technical al and and procedu procedural ral changes, the profession of structural engineering has continued to be an integral part of the delivery of services to the building construction industry and critical to the disaster resilience of th e country.

more academic underpinning for this. I became active in a joint e ff ort ort in the Caribbean during the 1980s and 1990s, attempting to develop appropriate building codes

 The twin hazar hazards ds of of earthqua earthquakes kes and and hurrica hurricanes nes ensure that structural engineers will continue to

What does the future hold?

Opinion

be vital to society in Jamaica and the Caribbean.  The averag average e member member of the the public public is often often not fully aware of this, as these disaster events often have a long recurrence interval, of the order of 25 years and more. However,, even small developing countries However such as Jamaica have begun to focus on the development and implementation of appropriate building codes to ensure professional design standards for all buildings. Furthermore, the creation of Offi ces of Disaster Preparedness in our territories has initiated public education programmes aimed at keeping the public informed about the risks and likely consequences of these disasters.  The IStru IStructE’ ctE’s Caribb Caribbean ean Regio Regional nal Grou Group, p, headquartered in Trinidad, Trinidad, has been working to sustain local relationships with the IStructE, starting with student bodies and CPD in conjunction with the JIE.  These eff orts orts need to continue.

 

Alfrico Adams

 

CEng, FIStructE, FJIE, MASCE

Alfrico is Principal of SMADA Consultants Ltd., Jamaica. He has been responsible for a wide range of structures and for promoting continuing professional development. He was President of the Jamaica Institution of Engineers in 1984.

New How guidance: to calculate embodied carbon Learn how to calculate embodied

              

––– PDF: Free Print: Member: £18.85 | Standard: £29

20844_new_guidance_half page_SEPT.indd 1

www.istructe.info/calculating-carbon

08/09/2020 09:41

41 thestructuralengineer.org | October 2020    

Opinion

Book review

 

Review This concise book provides useful information and valuable guidelines for engineers looking to extend the service life of concrete structures, concludes Long-yuan Li. Li.

Durability of reinforced concrete structures  Authors  Auth ors::  Paul Chess and Warren Green Publisher: CRC Press £50 (hardback); Price:   Price: £15.30 (e-book) 978-0-367-27838-0 ISBN:

CHLORIDE-INDUCED CORROSION of CORROSION of reinforcing steel is one of the most important durability problems for reinforced concrete structures. The reinforcement corrosion not only reduces the strength of steel bars, but also leads to cracking, spalling and delamination of concrete cover, which can in turn accelerate the deterioration of steel corrosion.  This book book loo looks ks at the mec mechan hanism isms s for for corr corrosi osion on induced by chlorides and how corrosion engineering can be used to minimise these problems in future projects. It also discusses the eff ectiveness ectiveness of corrosion monitoring techniques and questions why the reality is at odds with current theory and

 The las lastt chap chapter ter of the boo book k prov provide ides s seve seven n case case studies in which concrete structures had suff ered ered from reinforcement corrosion and were treated using di ff erent erent repair methods. In addition, a subject index is also provided at the end of the book.  The boo book k was was writ written ten by two exp experie erience nced d prac practis tising ing engineers who are actively working in the field of corrosion remediation of concrete structures. Unlike other durability books, this book focuses more on the practical concerns of reinforcing steel corrosion problems in concrete structures and addresses the issues related to the design, monitoring, maintenance and treatment in order to protect reinforcing steel

s standards. tan ar s. Finally, na it provides several real-wo real-world examples in which reinforced reinfor concrete structures with corrosion problems are d described and various var ous life-enhancement e-en e-en solutions soutons souto ns that t at were considered and applied are discussed.  The boo book k co cont c ontain o ains s seven seven chapters. The first two chapters briefly introduc introduce the general problem of reinforced reinf  concrete structures and describe tthe e corrosion corro cor roson son process p of reinforcing steel induced by chlorides occur occurring in concrete structures. Chapter hapter 3 reviews re various techniques currently used for detecting an and monitoring reinforcing steel corrosion in concrete stru structures. Chapter 4 discusses the design issues in order to t achieve a speci fied design life by using

from corrosion.  Althoug  Alth ough h the the boo book k is condensed and succinct (137 pages), it provides very useful information and valuable guidelines for the enhancement of the service life of concrete structures. The book will serve as an excellent reference work for structural designers, specialist contractors, consultants and owners of corrosion-damaged structures. It will also be a valuable reference for civil engineering students at postgraduate level.

UNLIKE OTHER DURABILITY BOOKS, THIS BOOK FOCUSES MORE ON THE PRACTICAL CONCERNS OF REINFORCING STEEL CORROSION PROBLEMS IN CONCRETE STRUCTURES

diff erent erent life-enhancement life-enh techniques. Chapter Ch pterr 5 describes pte d the optimal maintenance strategies structural service life with minimal s at g es to to maximise m expenditure. x en it itur ure. e. Chapter 6 discusses the pros and cons of diiff erent erent remedi remediation procedures when they are applied to a structure at diff erent erent stages.

Long-yuan Li BEng, MSc, PhD, CEng, FIStructE Long-yuan Li is Professor of Structural Engineering at the University of Plymouth. His research interests are mainly related to concrete materials, including the durability of reinforced concrete structures, geopolymer concrete, and fire safety of concrete structures.

Enter a sketch in the next next competition – deadline 4 January 2021 next 2 21 The Drawing Board is The Structural Engineer’s  quarterly  quarterly sketching competition,  judged by Ron Slade FIStructE of WSP.

Sketches must be: • hand drawn (no CAD, except for ‘guided freehand’) • from a real project or assignment • at a suitable scale for publication (i.e. not too intricate/detailed). Please also submit a short description (150 words) to put the sketch into context.

To take part, submit your entries to: [email protected] Each published willfrom receive a free single entry e-book the Institution’s current list of titles. Background sketch by Kevin Lyons (Lyons O’Neill) 

42 October 2020 | thestructuralengineer.org

 

Letters

 

Opinion

 

 Ve  V eru rullam Readers’ letters, comments and queries

Golden advice DAVID BRETT What an inspiring and thought-provoking Gold Medal address from former VicePresident Mike Cook. I was also privileged to meet Ted Happold at Arup, and work closely with two distinguished former Presidents there, Peter Dunican and Peter Campbell. Having brilliant engineers as role models and mentors is an invaluable experience for young engineers, so I completely agree with his recommendation for having ‘allies’. His ideas of ‘co-creation’ and ‘drawn thought’ demonstrate how important it is to work closely with colleagues in the design team, and to think creatively. There is no monopoly of good ideas, so we can all learn from our colleagues.  The use of mode models ls is also some somethin thing g which helps all members of the team and clients to understand the complexities involved in construction, and to identify the best method.  The nee need d for for the the design design and construction team to be united in their eff orts orts to cut carbon is also commendable.  This is a rela relative tively ly new new aspec aspectt of of design design and construction which needs to be considered carefully now and presents new problems such as the choice and reuse of materials and components. His example of ‘doughnut economics’ was intriguing, as investors are now pressuring companies to produce sustainable solutions and consider climate change in all their activities. As he so rightly summed up: ‘The climate has no borders’.

Watch the address  You can wat  You watch ch a reco recordi rding ng of Mik Mike e Cook’s Cook’ s Gold Medal address at www.istructe.org/resources/  career-profiles/mike-cookgold-medal-address-2020/ .

Neither the climate nor of the other challenges wemany face have borders. We should be proud that our institution is international and, if we are to make headway in solving many  of the problems we all share, either

domestically or globally, then the best we can do is cooperate and learn from each other. Including ‘across borders’: we have the forum to do that.

 Accept  Acce ptin ing g ethical responsibility  MATTHEW CHURCH I found the profile of Mike Cook in the  August issu  August issue e of of The Structural Engineer thought-provoking. I’m encouraged to hear that Dr Cook believes that we should consider the ethical value of the projects we are working on. As he says: ‘We must resist the pressure to build the wrong things. It is up to us to embed climate accountability into our work’.  This is a gre great at star start, t, but but I ask ask wheth whether er our moral responsibility and accountability should not also apply to all three aspects of sustainability. If we are to build enduring solutions for humanity as a whole, we must consider the economic and social aspects of our work too. The impact the project is having on the socioeconomic surroundings and whether that is positive or negative needs also to be considered. It is all well and good to pursue an environmental design, but it should not come at a significant cost to the current or future generations in other ways, if it is to be truly sustainable.  The socioecono oeconomic mic aspe aspect ct of this this is particularly clear when exporting our services to countries with poor human rights records and where corruption is present, e.g. a Human Rights Watch report p published u s e in n August ugus 1 showed ug s owe that a p people eop e who have eff ectively ectively become indentured

HAVE  YOU  YO UR SAY  SA Y 

Send letters to…  All contributions to Verulam Verulam should be submitted via email to:  to:  [email protected] Contributions may be edited on the grounds of style and/or length by the Institution's publishing department.

servants are still being used to construct the projects surrounding the Qatar World Cup preparations, which many UK-based companies have contributed to. In the past, structural engineers have washed their hands of their ethical responsibility in these matters, using many of the same arguments that Mike Cook argues we should no longer use to support environmentally unsustainable buildings. So, therefore, I argue that the questions ‘Could you have stopped this? Did you try?’ should be applied to the full accountability of our role. If we are to accept some of our ethical responsibility, we should accept all of it.

REFERENCE 1) Human Rights Watch (2020) ‘How Can We Work Without Wages?’ Salary Abuses Facing Migrant Workers Ahead of Qatar’s FIFA World Cup 2022 [Online] Available at: www.hrw.

org/report/2020/08/24/how-can-we-workwithout-wages/salary-abuses-facing-migrantworkers-ahead-qatars (Accessed: October 2020)

The points Matthew raises are certainly worthy of debate, but the issues are extremely diffi cult ones. On a positive note, engineers do much for humanity in providing essential infrastructure to those much less fortunate than ourselves. We can also be reminded that one of our previous Gold Medallists (Jo da Silva) was honoured for her humanitarian work in coping with natural disasters. And one of our Presidents (Bob McKittrick) focused on eliminating corruption from the construction industry. His update on the UK Anti-Corruption u Forum was published in The Structural F  Engine  Eng ineer  er  in  in November 2012.

Embodied carbon limits iin the Building Regs?  ANDY  AND Y ROLF RO LF that the IStructE is It is clearly fantastic pushing forward the discussion about p tthe embodied carbon of our engineering designs. Recent articles reinforce the need d tto change and how urgent this is. However,

43 thestructuralengineer.org thestructuralengineer .org | October 2020 2019

   

Opinion  Letters

what is next? How do we really push for change? In my own experience, we can continue to raise awareness, advocate for better design and provide lower-carbon solutions and options, but too often we meet resistance from outside our own discipline.  The res resista istance nce ofte often n comin coming g from from those those who have ‘declared’ a willingness to change. This means we only ever aspire to be better. I suggest a more radical move to align the construction stage of a project with that of regulatory guidance for the operational stage. Having the equivalent to Building Regulations Part L, but setting embodied carbon limits for new construction. What would stop this happening? We can all get the feeling that concern about the climate emergency is not a passing whim. Hurricane Laura is a foretaste of the consequences with graphic illustrations of the effects on infrastructure. The IStructE has a task force: no doubt it will be considering  Andy’  And y’s s comm comment ents s along along wit with h all all other other letters.

Effi cient use of materials  ALAN  ALA N PEMB PEMBER ERTON TON While I am very pleased to see the numerous recent articles and letters relating to our role as structural engineers in combatting climate change, I genuinely fear that this could be a case of ‘shutting the stable door after the horse has bolted’, rather than ‘better late than never’. Having spent most of my 40 years plus in the industry as a design consultant, I now find myself back working for a contracting company, mainly advising on tenders. Time and time again, I see structural designs prepared at tender stage using vastly more material than is necessary. Just yesterday I was able to identify a saving of 150m3 of excavation as a result of first saving 150m3 of  in  in situ concrete situ concrete in a basement scheme. That’s 20 concrete wagons! There will of course be further savings in the amount of piling to the tune of 400t load due to the consequent reduction in the building’s self-weight.  Apartt from  Apar from the the pote potentia ntiall cost cost savin saving g to the client and reduced programme time, this material represents an enormous amount of embodied carbon. I haven’t had to use a complex or innovative methodology to come upthe withdrawings this, just and and hour or so going through doing a couple of check calculations. I wouldn’t be writing this if it was an isolated incident, but I am afraid it follows a pattern of over-design that I see day in,

day out. I welcome the developments in the design process that will help us identify where savings in the embodied carbon in buildings can be made by structural engineers. However, I would ask that, in the meantime, the more experienced engineers among us spend an hour or so early on during the development of their organisation’s designs just asking themselves if they are producing a design that really makes the most effi cient use of our planet’s precious resources.  Alan’s undo  Alan’ undoubt ubted ed des design ign exp experie erience nce suggests this was a valid saving exercise. But Verulam believes that apart from endorsing the general process, many of our less experienced colleagues would benefit from details of just how such savings can be made. Can readers supply (anonymised) examples?

Clarity in terminology  MELVIN HURST I was intrigued to see the cover of the September issue of The Structural Engineer , with the use of ‘MMC’ in the title. What was this magic new material that would save the world, I wondered? I assumed that the ‘C’ stood for carbon, a word that is ubiquitous in the engineering literature these days. However, I soon discovered that MMC stood for ‘modern methods of construction’. In my day, initialisms could serve a useful purpose, such as HAC for ‘high alumina cement’ and, of course, RC. We didn’t go around talking about ‘SE’, ‘RSs’ or ‘SF’; instead we just referred to ‘sound engineering’, ‘robust structures’ and ‘solid foundations’, all essential to good construction. I daresay it is a generational thing, and younger engineers may feel more comfortable with initialisms for everyday expressions (I only have to think of LOL in text messages) but, really, while OSM serves a useful purpose, and indeed would have been a better fit for the cover title, in the context used here does the catch-all MMC really do the same?  Verul  V  V  erulam am con confess fesses es to to igno ignoranc rance e about about what MMC meant! w

Not so modern methods of construction DAVID BRETT D Congratulations to the authors of the C

excellent article, ‘Refocusing modern methods of construction on the climate emergency: a five-capitals model for action’, in the September issue of The Structural Engineer . However, MMC is not quite so modern, as we experimented with similar methods in the 1960s and 1970s. We are more aware of using recycled materials, decarbonisation and climate change, but the basic principles are the same. CLASP (Consortium of Local  Authorit  Auth orities ies Spec Special ial Pro Program gramme) me),, particularly for schools in mining subsidence areas, SCOLA (Second Consortium of Local Authorities), and SEAC (South Eastern Architects Collaboration), were all reasonably successful in their day, as they were not in competition – except for the components. Probably the most successful was the ‘dry envelope’ method of construction, which was researched by the NBA (National Building Agency) and developed by the Conder Group. This is the only method of construction to have been awarded the Queen’s Award for Technological Innovation, after being used for over 1000 projects for offi ces, schools, hospitals, hotels, and civic centres.  The idea was to const construct ruct a weathertight shell (the dry envelope) so that work could proceed inside and out at the same time. This more than halved normal construction periods, as it was basically bolted and screwed together. It had a steel frame with precast concrete floors and wall planks, aluminium windows and sills, and a profiled metal roof.  The con constru structio ction n metho method d allow allowed ed for for virtually any type of plan, elevations (up to four storeys), external and internal finishes and services, so could be tailored to the requirements of the client. It became very popular with both clients and their architects, as the construction method allowed tremendous freedom of design. It was also very competitive compared with traditional construction and did not require an army of skilled construction workers to complete. It could also be dismantled and most of the components reused if required.  There  The re are man manyy lesson lessons s we can learn from past successes (and failures) of so-called ‘modern methods of construction’, and this is one of them.

Perhaps is a has deeper lesson here andthere one that been increasingly reflected in many articles published in The Structural  Engine  Eng ineer  er  over  over the last few years. That lesson is that ‘design’ is

44 October 2020 | thestructuralengineer.org

 

Letters

 

not just about member sizing: it’s also about ‘buildability’, which includes understanding products and construction techniques on the market and means recognising the aims of the programme.

Engineering Enginee ring in the domestic sector revisited DAVE PEXTON I have read with great interest the letters that first appeared under ‘Engineering in the domestic sector’ from May 2019, as I run my own consultancy within this area. I was called by the owner of a house who had received both planning and Building Regulations approval, There was no design of any steelwork and none shown on the drawings, so the builder wanted to know what to provide. It was a semi-detached property with the complete wall between ground and first floor removed, giving a clearance of around 6.8M. When I arrived, I decided that we would need a sway frame, after considered thought of other possible solutions.  The builder, der, in his infinite wisdom, said, ‘No way, I’ve built scores of these openings, mate, and provided a foundation around 700mm square overlaying the existing party wall footing on one side and never have they failed, all with a nominal brick pier at the ends’. I questioned him about the eccentric loading on the foundation adjoining the party wall and ground-bearing pressures – to which his reply was, ‘What eccentricity?’ – as well as the minimum dimension for the pier not being as required under Approved Document A, let alone the design of same. I spoke with the client, who understood my reasoning for a frame and was willing to pay me a retainer so that I could turn around my design ASAP. I then spoke with her husband over the phone and agreed that I would do nothing until he returned home later that day to discuss the project with his wife. Needless to say, the builder had his way.  This worrie worries s me me as as to how the these se situations obtain Building Regulations approval.  Yes,  Y es, the swa swayy frame frame is costl costly. Now to the point: in a terraced block of three, four, five or even six houses, with the current trend of opening up the rear of a house to provide a large open area without the need for brick piers to conform to the Building Regulations, do you put that a sway frame in, as youwhen can easily argue the other properties are supporting each other? It’s diffi cult to argue that the client needs a frame when they say no one else has

removed their walls. OK, a semi-detached is easier to argue, and even a threeproperty terrace can be discussed and reasons given why a frame is needed. What do other engineers consider as to when a frame is needed in a terraced block? Should the designs be undertaken by members of the Institutions of Structural and Civil Engineers? The basic principles of stability are immutable. If we (as the UK government does) ‘follow the science’ and ask ourselves what stops the building swaying sideways, the answer is clear in this case: not much. Several previous contributors have come to the same conclusion. Many in practice seem to feel that the skills in Building Regulations departments are not what they once were, and that should concern us all.

Checking spreadsheet calculations ROBERT WODEHOUSE During August, I read with dismay that an NHS commission has found errors in spreadsheets used for calculating air changes in a hospital ward. This subsequently required £16M of repairs/  modifications to the hospital concerned. Other hospitals may also be aff ected ected May I use Verulam to urge that, when spreadsheets are used, hand calculations should be carried out to justify the ‘design principle’ and ‘approximate design values’ to obtain suffi cient confidence levels that would suit any insurer. I know hand calculations are considered ‘démodé’, but they allow the engineer to follow through the design principles from start to finish and to take into account any local design impact or last-minute design requirements, etc.

Opinion

before committing to construction.  Anything  Anythi ng tha thatt repe repeats ats ext extens ensive ively ly should be fully checked: get one wrong and you get them all wrong.  Any rea reader der tip tips? s?

British Steel turns back the clock  ALAST  ALA STAIR AIR HUG HUGHE HES S I recently had occasion to look up British Steel’s online section properties table. While wishing our new Chinese-owned national champion every success in its eff orts orts to regain the crown of most effi cient primary producer in Europe, I was horrified to see it reverting to old-style pre-Eurocode symbols and axes. In other words,  h is back to D, t f  is T , It  is H, M  y  is M  x , etc. (But not consistently: angles, IPE, HE and – strangest of all – beams for the American market continue to use Euro-symbolism!) What may have seemed an appealing populist move to a marketing person in North Lincolnshire is a recipe for neverending confusion in structural engineering practice. It might delight the odd diehard who has never made the change, but for the majority there is no wish to put the clock back.  This view will be sha shared red by many many reluctant converts; having put ourselves through years of painful adaptation, we deserve a break from re-education. There’s There’s a strong safety argument for leaving things alone, especially where the axis convention is concerned. The UK is part of Europe and remains committed to the Eurocodes. Can British Steel be persuaded to perform a diplomatic U-turn before it is too late?  At least east Briti British sh Stee Steell has has no no truc truck k with with the decimal comma. If only we could persuade BSI to declare that in future everything it publishes will use proper decimal points. That would be the right kind of populist move, one we could applaud!

Robert is absolutely right. But rather than looking at this as an isolated incident, we would all do well to reflect on the thorny question of how we can be assured that our calculations are fault free. The history of failures is littered with examples of gross errors which, in hindsight, raise astonishment that they could have been overlooked. Before designs start, it is as well to draft a ‘basis’ with all key parameters

 Alastair  Alasta ir is wis wise. e. The The hist history ory of failures contains several simply due to dimensional mix-ups. The unit mix-up on the Mar  Mars s Clim Climate ate Orb Orbite iter  r   (1998) is legendary. The Vasa warship capsized in 1628. Its asymmetrical hull resulted from one side being set out in Amsterdam ‘feet’ and the other in Swedish ‘feet’. There was also near disaster on a steel structure designed

set and have that rigorously veriout fied. Thereafter check in stages. Don’t start any member designs until after the analysis has been verified. As Robert suggests, always make sure that designs are ‘about right’ (by WL /8)

in Europe and fabricated UK. Fillet welds were defined in in the mm: but at that time the UK definition of size was via leg and the European size was defined by throat (30% difference). Standardise and change nothing!

45 thestructuralengineer.org thestructuralengineer .org | October 2020 2019

 At the  back Diary dates  

Unless otherwise stated, evening technical meetings start at 18:00 with refreshments from 17:30 and are free of charge to attend. History Study Group meetings start at 18:00 and are free of charge to attend. Registration is not required except for the  Annual  Annu al Busines Business s Meeting Meeting held held in January.   Industry workshops and CPD courses are held at HQ unless otherwise stated.

ONLINE LECTURE Tuesday 27 October Designing with nature Hugh Dutton 18:00–19:30 Price: Free Registration: www.istructe.org/events

ONLINE CPD COURSES Monday 19 October

Dia iarr y dat dates es Note that more current information may be available from the Institution website: www.istructe.org/events

WEBINARS Tuesday 20 October Maritime engineering Gareth Evans and William Evans 12:30–13:45 Price: Members £45.50 + VAT; Standard £70 + VAT Registration: www.istructe.org/events Friday 6 November The Structural Awards: an insider’ insider’s s view Tim Ibell, Tanya De Hoog and Ian Firth 16:00–17:00 Price: Free Registration: www.istructe.org/events

10:00–17:30 Price: £265 + VAT (Early Bird) Registration: www.istructe.org/events

Friday 6 November Engineering skills for humanitarian needs Jo de Serrano, Andrew Lamb and Richard Luff 14:00–15:00 Price: Free Registration: www.istructe.org/events

Monday 19–Tuesday 20 October Temporary works design Ray Filip 10:00–17:30 Price: Members £425 + VAT; Standard £555 + VAT VA T Registration: www.istructe.org/events

Friday 6 November The art of persuasion and collaboration Will Arnold, Roma Agrawal and Martin Knight 10:00–11:00 Price: Free Registration: www.istructe.org/events

ONLINE CPD COURSES

REGIONAL GROUPS

Design of retaining walls to Eurocode 7 for small practitioners Chris Gough

Wednesday 21 October Effective marketing for SMEs Parag Prasad 14:00–18:00 Price: Members £125 + VAT; Standard £165 + VAT (save 20% with discount code SKILLS20) Registration: www.istructe.org/events Thursday 22 October Stadium design  Angus Corm Cormie ie 10:00–17:30 Price: Members £265 + VAT; Standard £345 + VAT Registration: www.istructe.org/events

Tuesday 24 November Regional Group AGM and technical seminar on mechanical ground anchors Tim Hall 17:30 Registration: www.istructe.org/events/midlandcounties/mcrg-agm-and-talk-on-mechanicalground-anchors/ 

North Thames Thursday 22 October Regional Group AGM and talk on Admiralty Arch Diego Padilla Philipps 18:00–19:15

Registration: www.istructe.org/events/norththames/agm-(ntrg)-and-technical-talk-on-admiraltyarch-by/ 

 INTERNATIONAL

CONFERENCES

  Seattle, WA, USA    Wednesday 10–Saturday 13 March 2021 SEI Structures Congress 2021 Washington State Convention Center, Seattle, WA, USA 

Registration: Opens 4 November 2020 Further information:  www.structurescongress.org/  Contact: [email protected]

 

Chester and North Wales Thursday 12 November Statutory planning consent process Matthew Fox 18:00–19:30 Registration: www.istructe.org/events/  chester-north-wales/statutory-planningconsent-process/ 

Midland Counties

Monday 26 October

Wednesday 21 October Temporary works excavation support –

Eurocode 5: The essentials of timber design Keerthi Ranasinghe

challenges Rob Eagles for the supply chain

10:00–17:30 Price: Members £265 + VAT; Standard £345 + VAT Registration: www.istructe.org/events

17:30

Registration: www.istructe.org/events/  midland-counties/temporary-worksmidland-counties/tempora ry-worksexcavation-support-challenges/ 

Sheffi eld, UK    Wednesday 1–Friday 3 September 2021 Eurosteel 2021 (postponed from 2020) The Diamond, University of Sheffi eld, UK Registration: Temporarily closed. Re-opens on 1 January 2021. Delegates who have already registered for September 2020 will be eligible for a full refund. Further information:  https://eurosteel2020.com/ 

Regional Group Committee members should submit details of forthcoming events to: [email protected]

46 October 2020 | thestructuralengineer.org

 

Spotlight on Structures  At the back

 Access to Structures is free to paying-grade Institution members as one of their membership benefits, via the ‘My account’ section of the Institution website. The journal is available online at: www. structuresjournal.org

Read the latest issue  The latest issue of Structures (Volume 27, October 2020) is available at www. sciencedirect.com/journal/structures/vol/27.. sciencedirect.com/journal/structures/vol/27 Editor-in-Chief, Leroy Gardner, has selected a paper on ‘Performance of a novel slider device in multi-storey cold-formed steel modular buildings under seismic loading’ as his ‘Featured Article’ from this issue. The article will be available free of charge for six months.

Editor-in-Chief’s Featured  Article Performance of a novel slider device in multi-storey cold-formed steel modular buildings under seismic loading John Jinga, G. Charles Cliftonb, Krishanu Royb, James B.P. Limb a  Tino Structures (Structural Consulting Engineers), Auckland, New Zealand b  Department of Civil and Environmental Engineering, The University of Auckland, New Zealand Highlights model was used to Ò| A validated numerical model analyze a six-storey modular steel building under earthquake loading. Ò| The six-storey building had a proposed slider device installed at each levels. Ò| The proposed sliding system in the sixstorey modular steel structure was capable of achieving all the desired performance objectives. Ò| When subjected to the scaled earthquakes, the modules slid in alternate directions at diff erent erent floor levels within a maximum displacement defined by the 2.5% drift requirement. Ò| Maximum energy dissipation of more than 80% was observed through friction and rubber hysteresis in the proposed system.  Abstract  A 0.25-scale three-storey three-storey stacked modular modular steel structure, with a novel slider device used fl

at each oor level, was built, and subjected s ubjected

to seismic biaxial base excitation in a series of shake table tests. The test results were

building. The applied gravity loads for each module were also the same as that in the

reported in the literature by the first author of this paper, which showed that the proposed slider device and the modular steel structure performed well under seismic loading.  This paper extends the work of previously reported shake table tests by developing a numerical model. The numerical model has been validated against the test results of the three-storey modular structure. The validated numerical model has then been extended to a six-storey structure consisting of six modules in total (one unit at each floor) with the same material, link, member and constraint properties as used in the three-storey

three-storey test structure. The six-storey three-storey structure has been subjected to a range of earthquake records from the El Centro, Delta, Kalamata, Chihuahua, Corinthos, Westmorland and Chi-Chi earthquakes that occurred in the past; all these records were scaled according to the loading standard (AS/NZS 1170) for a design site located in Wellington City, New Zealand. These further analysis results on a six-storey modular structure provide a better indication of how a full-scale perfectly built multi-storey modular steel structure with the slider units behaves in practice. As revealed by the analysis results, the proposed sliding system in the six-storey modular steel structure can achieve all the desired performance objectives. When subjected to the scaled earthquake records applied in both the longitudinal and transverse directions, the modules slide in alternate directions at diff erent erent floor levels within a maximum displacement defined by the 2.5% drift requirement and subsequently self-centered within a tolerance of 5mm at the conclusion of the severe shaking. While sliding, all modules remain stable and were not prone to any collapse and soft-storey failure at lower levels. During the severe shaking, more than 80% of the seismic input energy is dissipated through friction and rubber hysteresis in the proposed system. Ò|

Read the full paper at https://doi.

org/10.1016/j.istruc.2020.05.051

Register for alerts If you’d like to receive regular updates about new content in  Structures, register for email alerts at www.sciencedirect.com/ . www.sciencedirect.com/ .

47 thestructuralengineer.org | October 2020

 

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New cored wire for high strength steel welding ESAB has added Coreweld 55 LT H to its series of metal cored wire designed for welding high strength steel. The lower alloy wire (1.3% Ni) offers a typical impact toughness of 110J at -60oC, a yield strength greater greater than 550MPa, a tensile strength of 670MPa and less than 4ml diffusible hydrogen/100g hydrogen/100g of deposited weld metal. It provides a smooth, stable arc at high welding speeds while minimising spatter and silica islands. Further information: ESAB (web: esab.co.uk)

Providing a standard solution to groundworks design Mabey has introduced the MyConstruct portal alongside the launch of its new website, Mabey Hire. The online intelligent digital tool provides customers with access to over 500 standard temporary works solutions for low-risk groundworks projects. The database of pre-engineered groundworks solutions should help reduce the turnaround time from enquiry to delivery of equipment on site for low-risk excavations. Every solution has been created as a Standard Solution, as defined in BS 5975:2019 section 13.10. Further information: Mabey Hire: (web: www.mabeyhire.co.uk) REINFORCED CONCRETE DETAI DETAILING LING

R.C. Detailing Specialists Established 1980 Extensive experience Proven reliability Large capacity Paul Benham Ltd

 W   AN NT TO  A  AD  A DVERTISE  YO  Y OUR PRODUCTS  & PRODUCTS SERVICES HERE?

Civil & Structural Engineering Draughting Service

[email protected] www.paulbenhams.co.uk

Contact 020 7880 6245 or 6245 or email [email protected]

01273 730956

TheeStructuralEngineer Th The e flagship publication n of The Institution of Structural Engineers

48 October 2020 | thestructuralengineer.org

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Services Directory 

 

SOFTWARE

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SCALE Structural Calculations Introducing SCALE 5 for iPad, including: ●

STRAP software for analysis and design of cold formed, concrete, steel and pre & post-tensioned structures.

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SCALE 5 for Windows is also available for PC/laptop users. See www.fitzroy.com for details.

Fitzroy Systems Software for Structural Engineers

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49 thestructuralengineer.org | October 2020

Recruitment

 Telephone:  T elephone: +44 (0)20 7324 2755 Email: [email protected]  [email protected] 

 

PART ART--TIME TIME,, HOME H OME BASED CHARTERED STRUCTURAL ENGINEER

B S C

. . .

Beaumont Structural Consultants

We are a small structural and civil consultancy practice establish estab lished ed over 30 years years ago. ago. Once the current restric tions on travel are lifted, we will need one or two more chartered structural engineers based in certain areas of London and the South-East to handle jobs local to them on a self-employed, sub-consultant basis but covered by our professional indemnity and public liability insurance. We are recruiting now in order to be ready for the expected surge in enquiries.

Due to current high workloads in Jersey we are currently looking for:

SENIOR STRUCTURAL/CIVIL ENGINEER Proficiency in building design requir required ed including familiarity with steel, concrete, masonry and timber. Minimum 4 years relevant experience. experience. Applicants with Chartered status will have the opportunity to progress to Director level.

You would be working from your own home an d can choose the hours you work and how many jobs you take on, typically two days a week. The work involves mainly inspections and reports on building defects and structural design of alterations and extensions, both domestic and commercial. It would suit a person who’s taken early retirement but wishes to keep their hand in. Must be chartered and able to write good English. We pay around £250 for a typical inspection and report, and £35 per hour for design work. No formal contract is involved.

STRUCTURAL ENGINEERING TECHNICIAN Experience in structural detailing in AutoCAD required required with Revit/BIM knowledge advantageous. All levels considered and excellent remuneration packages. Accommodation available if requir required. ed.

All new enquiries and invoicing are handled at head of󰁦ice, so you would not need to get involved in red tape. We would expect you to have a computer, an A3 printer, 8m tape, 600mm spirit level, digital camera etc. Autocad is preferable but not essential.

Applications will be treated in the strictest confidence. confidence. Apply in writing or via email to: Barry Helm, B.S.C. Ltd Goose Green Marsh, Beaumont, St Peter, Jersey, JE3 7BU Email: [email protected]

Beaumont Structures QPV indd

1

29/09/2020

A multi-disciplinary building and structural engineering engin eering practice, we are working with major organisations such as Cornwall Council, the Scottish Government, Prime Contractors and Property Developers. Based at our Cornwall Offices in St Agnes, we operate throughout Cornwall and the UK. The work environment is wonderful, close to some of the best surfing beaches, with amazing coastal walks. Within 30 minutes of Truro and the Newquay Airport. A great place to live and work. We are recruiting an experienced Structural or Civil Engineer with expertise to include Job Control, Client Liaison and Business Development. 3 to 5 years’ experience experience in a UK Design Office, working with common plus TEDDS/SCIA/TEKLA and AutoCAD/ TurboCAD.

If you are interested, please see our web site: www.abbott-holliday.co.uk and www.abbott-holliday.co.uk  and write to Peter Holliday at Wissenden Oast, Bethersden, Kent, TN26 3EL or email [email protected] [email protected]..

11:37

PART TIME, HOME BASED CHARTERED STRUCTURAL / CIVIL ENGINEER Structures Made Easy Limited is a London based structural engineering firm and is currently looking for a Chartered Senior Structural / Civil Engineer who has solid track experience in the following areas :• Structural surveys & reports in London • London basement extensions • Temporary works & method statements The criteria of this job advert is restricted to at least one or all of the three bullet points above. Please only apply if you have extensive experience in the above areas and are able to carry out your own site visits in London. The work required will be on a regular adhoc basis. We are looking for a candidate who is motivated and willing to start & deliver work relatively quickly.

Salary: £40,000 and £50,000. Discretionary bonus after 12 months. Please provide a written CV by email to [email protected] or post to Mr Philip Desmonde, The Old Bank, 48, Vicarage Road, St Agnes, Cornwall TR5 0TG

If you are interested please send an email with your CV and examples of recent work to [email protected] or contact us on 07525 047 778 for more details.

50 October 2020 | thestructuralengineer.org

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Recruitment

 

Jobs  Attract the for right ca ndidate candidate  Advertise just £379 for less -  Only The Institution of Structural Engineers can provide such a dedicated and receptive audience, whose experience and creative abilities are sufficiently diverse di verse to fill any vacancy, regardless regardless of seniority. Our five options offer various levels of targeting and visibility. These include:

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Job board ad live for 1 month,

Job board ad live for up to 3 months,

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£1,575

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RAPID RESPONSE

Job board ad live for 1 month, with logo Featured in top section of search results Included on two job newsletters ¼ page in The Structural Engineer  Targeted email sent to matching candidates

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Call 020 7     or email [email protected] to book your advertising today.

We managed to fill all the posts we advertised with the IStructE, and wish to thank you for the support and advice you provided during the process. I was really pleased with the spread and quality of responses we received — and have even managed to find a suitable candidate for a European office as well as filling the UK roles. roles.

”

Stephen Oakden, BE Design

51 thestructuralengineer.org | October 2020

 

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