MS-Bridge Live Loading Assessment.rev 1

HART BUILDERS SDN BHD GOVERNMENT OF MALAYSIA

JABATAN KERJA RAYA SARAWAK METHOD STATEMENT FOR BRIDGE LOAINGD ASSESSMENT FOR BATUKAWA OLD BRIDGE PROGRAM MENILAI, MEMBAIKI / MENGGANTIKAN JABATAN DI JALAN PERSEKUTUAN NEGERI SARAWAK (FASA 2) PACKAGE B (1):

Proposed Design, Construction and Completion of the Approach Road and Associated Works Linking The New Batukawa Bridge, Kuching Division

PACKAGE B (2):

Proposed Design, Construction and Completion of Repair Works To The Existing Old Bridge, Caching Division CONTRACT NO.:PWD/HO/B134/2011

CONSULTANT ENGINEERS PERUNDING TCS CONSULTANT ENGINEER Lot 147 & 148, Section 12 KTLD, Jalan Ajibah Abol, 93400 Kuching Tel: 082-423731/231105/426548 Fax: 082-423637

CONTRACTOR HART BUILDERS SDN BHD 100, (2nd Floor), Jalan Petanak P.O. Box, Satok Pos Office Jalan Satok 93860 Kuching Tel: 082-237622 Fax: 082-247622

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CONTENTS

1.0

INTRODUCTION

3

2.0

REFERECES

3

3.0

MATERIAL

3

4.0

EQUIPMENT & MACHINERY

4

5.0

MANPOWER

4

6.0

FIELD TESTING

4

6.1

BRIDGE MONITORING

5

6.2

LOAD CARRYING CAPACITY ASSESSMENT

6

6.3

LOAD ASSESMENT WITH KNOWN WEIGHT TRUCK

7-8

7.0

SAFETY REQUIRMENT

9

8.0

QUALITY ASSURANCE

9

9.0

APPENDICES

9

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INTRODUCTION The federal government of Malaysia has a program of bridge upgrading, to refurbish and strengthen bridges to allow for increasing vehicle traffic and increasing axle loads. It’s main to improve the road transportation in the Sarawak State and cater the heavy traffic volume raised by the construction of residential homes at Batukawa – Matang District.

Experiment-based structural assessments of the old bridge were conducted before and after retrofit/ upgrading works. Each assessment exercise comprised two separate components; a load test carried out in a single day followed by analytical bridge model updating, and strain monitoring exercise lasting approximately one month. This paper focuses on the strain monitoring program to assess the bridge’s live loading and its structural condition prior to and post upgrading.

1.1

OBJECTIVE To carry out the structural assessment of the existing Batukawa bridge in order to determined the strengthen works required for the deck slab and steel girders. 

To determined type of fiber carbon wrapping, area to bond and layer or thickness required to increase the flexural strength of desk slab.



To determined the strengthen works for steel girders



To compare the current code of practice BD 37/01 with current traffic usage with the data obtained from the bridge live loading assessment and load carrying capacity (Full scale bridge loading)



To study the performance composite design in between of headed shear stud connectors which attach the reinforced concrete slab to the supporting structural steel stubs in a steel-girder.

2.0 REFERECES The work is carried out in accordance to the following: BD 37/01 Volume 1, Section 3, Part 14 LOADS FOR HIGHWAYS BRIDGES 3.0 MATERIAL  

Epoxy resin Non toxic silicon sealant Page 3 of 9

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4.0 EQUIPMENT & MACHINERY The equipment involved in the desk repair works according to type and suitability: 

 

Campbell scientifit CR 1000 data acquisition system -For vibrating wire and full bridged with interface (DAS) will be consisting of data logger module, optical interace cable, Power supply, support software etc. 30 channel RST Vibrating Wire Readout Model 2106 Encardio- Rite Vibrating Wire Piezometer model EDS-20V-AW – 28 nos

5.0 MANPOWER The typical manpower involved in the desk repair works according to type but not limit to: a) b) c) d)

GDS instruments technician (CR1000 system setup) Skilled Worker-Carrying out the and installation of strain gauge Safety officer/supervisor-implementing site safety procedures at site QA/QC Team - implementing QA/QC aspect.

6.0 FIELD TESTING Field testing was carried out before and after upgrading works and in each case this consisted of a load test (U p to 350 tonne) carried out in a single day, and strain and acceleration monitoring exercise lasting approximately one month. Only a summary of the results of the change of strain and subsequent analytical model updating is given here.

C-concrete S- Steel girders

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HART BUILDERS SDN BHD 6.1 BRIDGE MONITORING

The bridge monitoring program involved measurement of Vibrating Wire strain gauge at the bridge’s mid-span and support using a purpose made bridge monitoring system. The monitoring system consists of 28 nos weldable VW strain gauges which (8 located at the top and soffit of girders beam and 16 nos located at the concrete slab), and a data acquisition system.

Data acquisition can be set at equal time intervals (every minute) or triggered if the response exceeds a user-defined threshold. A major advantage of the system is that the data acquisition system is powered by 12 V batteries, facilitating use in remote sites. The strain gauges were mounted on the bridge soffit to Span 2 which located on the land side and longest span of 38.5m, before and after upgrading works, with each monitoring program lasting at least 20 days. Data acquisition was triggered by ambient traffic at selected levels of strain. The data acquisition unit was set to record dynamic strain time series and the peak strain value for a particular event.

At mid span 2

At Support Pier 2

Strain

Serial

Strain

Serial

Strain

Serial

Strain

Serial

Gauge

no.

Gauge

no.

Gauge

no.

Gauge

no.

C1

8720

C8

8735

C1

8700

C8

8698

C2

8719

C9

8702

C2

8718

C9

8713

S3

8730

S10

8737

S3

8708

S10

8695

C4

8741

C11

8725

C4

8728

C11

8703

C5

8692

C12

8735

C5

8709

C12

8723

C6

8704

S13

8734

C6

8733

S13

8694

C7

8693

S14

8696

C7

8736

S14

8740

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LOAD CARRYING CAPACITY ASSESSMENT The Safe Health Monitoring involved controlled truck (known weight) loading scenarios to permit measurement of the load paths and provide data to compare the measured results to a finite element (FE) model of the instrumented span (Span 2). Using an FE model in combination with the measured strain data, The FE model was adjusted to match the measured results by modifying various modeling parameters. The most important features of the model were that all deck elements were modeled. In combination with calibrated modification factors applied to the measured values, this FE model is believed to be a useful tool to represent the behavior of the structure to assist in assets the exiting bridge capacity by modeling the strain differential between the deck slab and steel girders. The verification of structural adequacy can be expressed in term of strain in the reinforced concrete for deck slab and steel girder as below: εu ≥ εL + εD Where εu is the yield strain, is the ultimate live load strain and is the dead and superimposed dead load strain. The most critical combination of dead and superimposed dead load and ultimate live load is εL + εD. The ultimate live load strains were estimated from the monitoring data, where the dead load and superimposed dead load strain were calculated from the analytical model assuming linear behavior.

(a) Running of finite element model based on the current code of practice BD 37/01 for the existing bridge which design with BS5400-1978. (b) Re-running of the above-mentioned finite element model to assess its capacity against the requirement of current code of practice BD 37/01.

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LOAD ASSESMENT WITH KNOWN WEIGHT TRUCK The bridge was analyzed for three applied traffic load arrangement. The bridge was required to test up to total weight of 350 ton. The traffic load was defined as 12 trucks containing crushers run of average of 29 ton each. By assuming each loaded weight sequence was 58 ton (2 trucks) and total of 6 increments (12 trucks) to contribute total of 350 ton. The truck was lined up with certain pattern to distribute the traffic load as required, as shown below: Loading Procedure for Traffic Load Test Applied Load

Minimum Time Period of Maintaining Load

Number of Trucks (nos)

Loaded Weight (tons)

0

0

20 minutes

2

58

20 minutes

4

116

20 minutes

6

174

20 minutes

8

232

20 minutes

10

290

20 minutes

12

348

30 minutes

10

290

15 minutes

8

232

15 minutes

6

174

15 minutes

4

116

15 minutes

2

58

15 minutes

0

0

15 minutes

No increment of load shall be applied until and unless the average of the strain gauge readings were stable.

The CR1000 data acquisition system is taking reading every 1 minute interval. Each loaded trucks lined up as the planned program. The each loaded trucks increment was remained for 30 minutes for the strain gauge to stable and recorded.

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HART BUILDERS SDN BHD Loaded at Support 2 Trucks arrangement pattern longitudinal view:

Trucks arrangement pattern plan view:

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7.0

SAFETY REQUIRMENT Sufficient Personal Protective Equipment (P.P.E) included safety hanger which the monitoring work at underneath the bridge. Flagman shall provide to ensure the vehicles/ trucks and bridge shall close during the load test carried out.

8.0

QUALITY ASSURANCE Verify the data recording to obtain the strain value with the loading pattern and sequence was followed accordingly.

9.0

APPENDICES No Attachment

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