# C Purlin Design

April 8, 2021 | Author: Anonymous | Category: N/A

#### Description

DESIGN OF PURLINS (COLD FORM SECTION) Purlin Designation P1

Modified By: Multibuild Consultants, Va JOB No.: DATE :

Input Data: Purlin Geometry Span of the purlin Spacing of the purlin No. of Sag rods Slope of the Roof

= = = =

5.500 M 1.15 M 1 10 deg.

Number of Spans = (for 1 or 2 spans, Bending Moment Coefficient is 8, for 3 or more spans, it is 10) (in case of Bending about minor axis, (No of spans)x(No of sagrods+1) is used.

3

= = = =

6 kg/sqm Automatically Calculated from Section properties 10 % 4 kg/sqm

= Automatically Calculated from Slope = 75 kg/sqm Additional Live Loads to be considered = 0 kg/sqm (For Design of Wall Girt (Cladding Runner), additional Live loads to be considered can be entered as -ve of LL on roof) (Live load will be 0 effectively) Wind Loads Basic Wind Speed 44 m/s Terrain Category 3 k1 1 Maximum Horizontal Dimension of Building 44 m k3 1 Hence, Bldg Class B Height of Top 8.25 m Based on the data on right, k2 is obtained from the tables k2 0.88 Ht of building at eaves level, h Width of the building, w Length of the Building, l Hence, h/w and l/w

= =

= = =

6.35 m 24 m 44 m 0.265 1.833

Based on the h/w and l/w, the values of Cpe is obtained from tables as noted below: Maximum Downward Cpe (include sign) -1.2 Maximum Upward Cpe (include sign) -0.8 Based on % of openings, Cpi is taken as +/-

0.7

y: Multibuild Consultants, Vapi 26.MBC.MWV.FGPM3 16-06-2017

ion properties

of LL on roof) will be 0 effectively)

Input Data: Purlin Section Being Checked Try

C 200x50x20x3.15

Yield stress of material Flange Width, b Depth of section d Thickness t Length of Lip lip_l Inner Bending Radius

2400 50 200 3.15 20 4.73

Area Zxx Zyy Ixx Iyy

9.86 53.50 7.89 535.00 29.20

Purlin Weight

KG/CM2 mm mm mm mm mm cm2 cm3 cm3 cm4 cm4

7.740 kg/sqm

Output Summary Section Properties OK?

Stresses Ok? Critical Stress Factor Deflection Check OK?

OK OK

Based on Section 9 of BS:5950 Part 5 – 1998 Based on IS 801 Clause 5.2.2.1

Ok 0.999 OK

Notes:

1. Section Properties Check based on Section 9 of B:5950 Part 5 is a guideline and not mandatory Hence, Design is considered Safe even if above check only is not okay but all other che 2. Currently, this design only works if full width is effective. If full width is not effective, this spreadsheet will report Failure in Stress Check 3. Not suitable currently for curved roofs. 4. Design is not suitable for varying spans of purlins (varying truss spacing)

e and not mandatory okay but all other checks are okay effective,

Z Purlin Design Created Report by Madurai ES Consultancy Services Pvt Ltd Cold Form Purlin Design Report

Modified By: Multibuild Consultants, Vapi User: Arif

Code Version: R1

Code Year: 2011

Revision History

R0: Basic Design with checks for Stresses and Deflection based on IS 800 only R1: Added Section property checks and Allowable Stress Calculations based on IS 801

JOB No.:

26.MBC.MWV.FGPM3

DATE :

16/6/17

Input Data: Purlin Geometry Span of the purlin Spacing of the purlin No. of Sag rods Slope of the Roof

= = = =

5.500 M 1.15 M 1 10 deg.

Number of Spans

=

3

Bending Moment Coefficients: Use 8 for Single/Two spans, 10 for 3 or more spans Bending Moment Coefficient for Mxx(BMCX) For Bending About Minor Axis, Number of spans= number of spans x (number of sagrods+1) Number of Spans about Minor Axis = Bending Moment Coefficient for Myy(BMCY) TRY PURLIN SIZE C 200x50x20x3.15 (IS 811) Cross Sectional Area of Purlin = Purlin Weight

10 6 10

9.86 cm2 7.740 kg/m 6.731 kg/sqm

=

(Area in sqcm x 0.785 kg/sqcm/m) in kg/m (Weight in kg/m)/spacing

6.000 6.731 0.673 4.000

10 % of purlin weight

kg/sqm kg/sqm kg/sqm kg/sqm

17.404 kg/sqm 0.174 kN/sqm

LIVE LOAD Live Load on Roof = 75 kg/sqm if slope is less than 10 degrees. If Slope is more than 10 degrees, LL = 75 – 2x(slope-10), subject to minimum of 40 kg/sqm Live load on Roof

75 KG/M2

=

0 KG/M2

75 kg/sqm 0.750 kN/sqm

WIND LOAD Basic Wind Speed Vb k1 k3

44 m/s 1 1

Terrain Category Maximum Horizontal Dimension of Building Hence, Building Class is Height of Top

3 44 m B 8.25 m

Based on the above data, k2 is obtained from the tables k2 0.88 Design Wind Speed Vz=k1.k2.k3.Vb Design Wind Pressure pz=0.6Vz^2 = Ht of building at eaves level, h

Page 5

38.72 m/s 899.543 N/sqm 0.900 kN/sqm =

6.35 m

Z Purlin Design Created Report by Madurai ES Consultancy Services Pvt Ltd Width of the building, w Length of the Building, l Hence, h/w and l/w

= = = =

Based on the h/w and l/w, the values of Cpe is obtained from tables as noted below: Maximum Downward Cpe (including sign) Maximum Upward Cpe (including sign) Based on % of openings, Cpi is taken as +/-

24 m 44 m 0.265 1.833

-1.2 -0.8 0.7

Wind Load is included in two load combinations – DL+WL and DL+LL+WL Since, Dead Load and Live Load are downward, DL+WL will be critical for the maximum upward wind force Similarly, DL+LL+WL will be critical for the maximum downward wind force WL1: Maximum Upward Wind Force – To be used in combination DL+WL1 Maximum Upward Cpe (including sign) Cpi to use (for upward, use -)

-1.2 -0.7

Hence, Cpe+Cpi =

-1.9

Design Wind Pressure pz

0.900 kN/sqm

Wind pressure for Purlin Design

-1.709 kN/sqm

WL2: Maximum Downward Wind Force – To be used in combination DL+LL+WL2 Maximum Downward Cpe (including sign) Cpi to use (for upward, use -)

-0.8 0.7

Hence, Cpe+Cpi =

-0.1

Design Wind Pressure pz

0.900 kN/sqm

Wind pressure for Purlin Design

-0.090 kN/sqm

Design Calculations: Primary Load Cases – Conversion of forces to Normal And Tangential Components Spacing of the purlin Slope of the Roof

= =

1.15 m 10 degrees

=

0.174 kN/sqm

DL Normal Component = DL x Spacing x cos(slope) = DL Tangential Component = DL x Spacing x sin(slope) =

0.197 kN/m 0.035 kN/m

0.750 kN/sqm

=

LL Normal Component = LL x Spacing x cos(slope) = LL Tangential Component = LL x Spacing x sin(slope) = Total Wind Load in WL1

=

0.849 kN/m 0.150 kN/m -1.709 kN/sqm

WL is normal to roof Hence, WL1 normal component = WL1 x Spacing = And, WL1 Tangential component =

-1.966 kN/m 0.000 kN/m

-0.090 kN/sqm

=

WL is normal to roof Hence, WL2 normal component = WL2 x Spacing = And, WL2 Tangential component =

-0.103 kN/m 0.000 kN/m

Page 6

Z Purlin Design Created Report by Madurai ES Consultancy Services Pvt Ltd DL+LL Normal Load Tangential Load

DL+WL1 1.046 0.185

-1.768 0.035

DL+LL+WL2 0.943 kN/m 0.185 kN/m

For Strength Design, 0.75 factor is applicable for combinations with Wind Load since 33.33% extra stress is allowed Hence, the components of load in the various load combinations for Strength design are DL+LL 0.75(DL+WL1) 0.75(DL+LL+WL2) Normal Load 1.046 -1.327 0.707 kN/m Tangential Load 0.185 0.026 0.138 kN/m Maximum Normal Component =

1.046 kN/m

Purlin Section Selected: Section Name

C 200x50x20x3.15

Yield stress of material Flange Width, b Depth of section d Thickness t Length of Lip lip_l Internal Bending radius Total bending Radius, rad

2400 50 200 3.15 20 4.73 7.88

Flange Width w/o bend, w = b – 2 x rad

34.24 mm

Purlin Weight

kg/sqcm mm mm mm mm mm mm

Area

9.86 cm2

Zxx

53.50 cm3

Zyy

7.89 cm3

Ixx

535.00 cm4

Iyy

29.20 cm4

= =

7.740 kg/m 6.731 kg/sqm

(Area in sqcm x 0.785 kg/sqcm/m) in kg/m (Weight in kg/m)/spacing

Design Calculations: Checking Basic Section Properties based on Section 9 of BS:5950 Part 5 – 1998 Check No. 1 – Overall Depth =L/45

Overall Depth 100t = L/45 =

200 mm 315 mm 122.222 mm

Hence

Ok

Check No. 2 – Overall Width of Compression Flange= b/5

Width of Lip B/5 =

20 mm 10 mm

Hence

OK

Check No. 4 – Total Width over both flanges >= L/60

Total Width over both flanges L/60 = Hence

96.85 mm 91.667 mm OK

Check No. 5 – Zxx of Purlin >= WL/1400 for Simply Supported Purlin and >=WL/1800 for Continuous Purlin

Zxx

=

53.50 cm3

W is normal component of unfactored distributed dead load plus imposed load in kN L is span of purlin in mm W= 5.756 kN

Page 7

Z Purlin Design Created Report by Madurai ES Consultancy Services Pvt Ltd L= Number of Spans = Hence, denominator =

5500 mm 3 1800

WL/denominator

17.587

Hence

Ok

Result 1: Check for Section Properties Based on BS 5950 Part 5 Sec.9:

OK

Design Calculations: Checking Basic Section Properties based on IS 801 for Lip of Purlin Minimum Depth of Lip shall be 2.8 x t x ((w/t)^2-281200/Fy)^(1/6) and not less than 4.8t t= w= Fy= w/t= 2.8 x t x ((w/t)^2-281200/Fy)^(1/6) 4.8t=

3.15 34.24 2400 10.87 8.810 15.12

Lip l=

mm mm kg/sqcm mm mm

20 mm

Hence

Ok

Lip is Edge stiffener only if w/t