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    Hat Purlin

    Uploaded by

    Aniket Dube
    The document summarizes the design of a purlin section. It provides input parameters for the section geometry and material properties. It then calculates section properties like area, moments of inertia, and section moduli. Load estimates are given for wind, dead, and live loads. The section is designed according to bending stress, shear stress, deflection, and combined bending and shear stress checks. All checks show the design is acceptable according to specified codes.

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    © All Rights Reserved
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    Hat Purlin

    Uploaded by

    Aniket Dube
    554 views3 pages
    The document summarizes the design of a purlin section. It provides input parameters for the section geometry and material properties. It then calculates section properties like area, moments of inertia, and section moduli. Load estimates are given for wind, dead, and live loads. The section is designed according to bending stress, shear stress, deflection, and combined bending and shear stress checks. All checks show the design is acceptable according to specified codes.

    Original Description:

    Hat purlin design

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    The document summarizes the design of a purlin section. It provides input parameters for the section geometry and material properties. It then calculates section properties like area, moments of inertia, and section moduli. Load estimates are given for wind, dead, and live loads. The section is designed according to bending stress, shear stress, deflection, and combined bending and shear stress checks. All checks show the design is acceptable according to specified codes.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    554 views3 pages

    Hat Purlin

    Uploaded by

    Aniket Dube
    The document summarizes the design of a purlin section. It provides input parameters for the section geometry and material properties. It then calculates section properties like area, moments of inertia, and section moduli. Load estimates are given for wind, dead, and live loads. The section is designed according to bending stress, shear stress, deflection, and combined bending and shear stress checks. All checks show the design is acceptable according to specified codes.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
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    The document discusses the properties, design checks and allowable stresses for a structural section as per IS 801.

    The cross-sectional area, moments of inertia, section moduli and weight per meter are calculated.

    Design checks are performed for bending stress due to wind, dead and live loads, deflection, lateral loads, shear and combined bending and shear stresses.

    PURLIN DESIGN SUMMARY

    SECTION 1: PROPERTIES OF SECTION

    INPUT PARAMETERS:

    (E)Thickness t = 0.90 mm
    (A)Overall Depth = 85.00 mm
    Radius of curvature = 2.00 mm
    "Alpha" = 1.00 For lipped sec.
    B' = 40.00 mm
    C' = 20.00 mm
    D' = 5.00 mm
    Gamma angle = 75.00 degree (Lip angle)
    A' = 85.00 mm

    (2) Sectional properties: COIL WIDTH = 260.54 mm

    (a) Cross Sectional Area = Ax = 234.49 mm2 Weight per meter = 1.84 Kg / m
    (b) Moment of Inertia about x-axis = Ix = 229,177.02 mm4 = 22.92 cm4
    (c) Moment of Inertia about y-axis = Iy = 293,068.55 mm4 = 29.31 cm4
    (I) Sectional modulus Zxx = 5,392.40 mm3 = 5.39 cm3
    (j) Sectional modulus Zyy = 7,326.71 mm3 = 7.33 cm3

    Estimation of loads:

    Roof slope = 1/ 2.10 i.e, 25 degrees.


    Wind pressure = 125.00 Kg/m2
    Dead load = 11.85 Kg/m2
    Live load = - Kg/m2
    So, DL+LL = 11.85 Kg/m2

    Purlin spacing = 0.99 m no. of sagrods = -


    Bay spacing = 3.200 m

    Effective U.D.L on the purlin along its major axis = 0.01 t/m and ,for DL = 0.01 t/m
    Effective U.D.L on the purlin along its minor axis = 0.01 t/m
    Effective U.D.L due to wind load = 0.12 t/m 1.23 kn/m
    Effective U.D.L due to wind + dead load = 0.11 t/m 1.10 kn/m

    Maximum moment in DL+LL condition = 0.01 t-m


    Maximum moment in DL+WL condition = 0.11 t-m
    Maximum moment in minor axis = 0.01 t-m
    Section Design: (As per IS:801)

    Section used are all 0.9 mm thick Yield strength = 550.00 Mpa (=Fy) 5,608.46 kgf/cm2
    Depth of section = 85.00 mm

    Sxc = 5,392.40 mm3


    d= 85.00 mm L2*Sxc = 4,433.27 0.18*π^2*E*Cb = 1,561.38
    Iyc = 146,534.27 mm4 d*Iyc Fy
    L= 3,200.00 mm
    E= 210,000.00 Mpa and, 0.9*π^2*E*Cb = 7,806.86
    Cb = 2.30 Fy

    Fb(1) =2Fy - Fy2 * L2*Sxc = 262.56 Mpa


    3 2.7*π^2*E*Cb d*Iyc

    Fb(2) =0.3*π^2*E*Cb* d*Iyc = 322.84 Mpa


    L2*Sxc

    In our case we shall have the allowable bending stress as = 262.56 Mpa

    Check for wind load:-


    Actual bending stress in the purlin = 204.83 < 1.0x allowable bending stress, hence O.K
    Deflection of the section = 16.04 mm
    Allowable deflection limit = 17.78 mm Hence O.K

    Check for Dead and Live load:-


    Actual bending stress in the purlin = 25.24 < 1.0 x allowable bending stress, hence O.K
    Deflection of the section = 2.90 mm
    Allowable deflection limit = 17.78 mm Hence O.K

    Check for lateral load:-


    Actual bending stress in the lateral direction = 13.71 Mpa < 1.0 x allowable bending stress,
    hence O.K
    Actual deflection in lateral direction = 1.67 mm
    Allowable deflection limit = 17.78 mm Hence O.K

    As per clause 6.4.1 of IS 801,allowed maximum average shear stress Fv in kgf/sqcm is calculated as

    Case 1: If h/t is less than 4590/sqrt(Fy), Fv=1275 x sqrt(Fy) / (h/t)


    Case 2: If h/t is more than 4590/sqrt(Fy), Fv=5850000 / (h/t)^2
    Both are subject to maximum 0.4Fy

    h = 85.00
    t = 0.90
    h/t = 94.44

    4590/sqrt(Fy) 61.29

    Case 1, Fv = 639.42 kgf/cm2 62.71 Mpa

    Case 2, Fv = 655.85 kgf/cm2 64.32 Mpa

    Actual shear = v = WL/2 = 1.75 kn


    Actual Shear Stress = v/dt = 0.023 kn/mm2 229.14 kgf/cm2 22.47
    Mpa
    Permissible shear stress (Fv) > Actual Shear Stress, Hence O.K
    As per clause 6.4.2 of IS 801 for the design check of allowable stress in combined shear and bending

    Fbw = 36560000/(h/t)^2
    Here, h/t already calculated above as = 94.44
    Fbw = 4,098.77 kgf/cm2 401.95 Mpa
    Basic Allowable Design Stress calculated earlier F = 0.6Fy

    F = 3,365.08 kgf/cm2 330.00 Mpa

    Fb actual (from bending moment calculations), Moment/ Zxx 208.04 Mpa

    Actual Stress < Allowable Stress, Hence Ok Hence O.K

    Combined Shear and Bending Stresses in Web

    As per clause 6.4.3 of IS 801 for the design check of allowable stress in combined shear and bending

    SQRT((fbw/Fbw)^2+(fv/Fv)^2) must be less than 1

    In this clause, Fbw is not restricted by 0.6Fy and Fv is not restricted by 0.4Fy

    Actual stresses already calculated are


    fbw 208.04 Mpa
    fv= 22.47 Mpa

    Fb allowable bending stress = 262.56 Mpa


    Fv = 62.71 Mpa

    fbw/Fbw = 0.79
    fv/Fv = 0.36

    SQRT of sum of squares = 0.87 < 1.00

    Hence O.K

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