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Cold Formed Steel Design Guide

This document provides details on the design of a cold formed lipped channel section according to BS5950. It includes: 1) Geometric details of the section including dimensions, number of bends, and material properties. 2) Calculations of section properties including gross and effective areas, moments of inertia, and radii of gyration. 3) Determination of effective widths accounting for local buckling. 4) Evaluation of design strengths in tension and compression accounting for cold working. 5) Assessment of the section's capacity for axial compression and torsional-flexural buckling.

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0% found this document useful (0 votes)
141 views8 pages

Cold Formed Steel Design Guide

This document provides details on the design of a cold formed lipped channel section according to BS5950. It includes: 1) Geometric details of the section including dimensions, number of bends, and material properties. 2) Calculations of section properties including gross and effective areas, moments of inertia, and radii of gyration. 3) Determination of effective widths accounting for local buckling. 4) Evaluation of design strengths in tension and compression accounting for cold working. 5) Assessment of the section's capacity for axial compression and torsional-flexural buckling.

Uploaded by

Salvatore Shw
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© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Cold formed sections BS5950Cold formed sections BS5950COLD FORMED THIN GAUGE SECTION DESIGN (BS5950-

5:1998)

y
+ve My 3

16
200

x x
Mx

0.1

75

Basic section details


Section details
Section name;
Section type; Lipped channel
Depth; D = 200 mm
Breadth of top flange; Bt = 75 mm
Breadth of bottom flange; Bb = 75 mm
O/all breadth; B = Bt = Bb = ;75; mm
Design thickness; t = 3.0 mm
Internal radius of bends; r = 0.1 mm
; ;;
Depth of top stiffening lip; DLt = 16 mm
Depth of bottom stiffening lip; DLb = 16 mm
The section breadth to stiffening lip depth ratio is less than or equal to 5 therefore the flanges are stiffened (cl 4.6)
Number of 90 degree bends; N90 = 4; ;
Design forces and moments
Ultimate axial load; F = 1.0 kN; (Compression);
Ultimate bending moment about x axis; Mx = ;23.20; kNm
; ;;
Ultimate positive bending moment about y axis; Myp = ;0.28; kNm
Ultimate negative bending moment about y axis; Myn = ;-0.51; kNm
Gross section properties
Area of element a; Aa = (DLt - t/2)  t = 44 mm2
Area of element b; Ab = (Bt - t)  t = 216 mm2
Area of element c; Ac = (D - t)  t = 591 mm2
Area of element d; Ad = (Bb - t)  t = 216 mm2
Area of element e; Ae = (DLb - t/2)  t = 44 mm2
Total gross area; Ag = Aa + Ab + Ac + Ad + Ae = ;1110; mm2
Position of x axis from centreline of flange; xbar = [Aa(D-t-(DLt-t/2)/2)+Ab(D-t)+Ac(D-t)/2+Ae(DLb - t/2)/2]/Ag
xbar = 98.5 mm
Second moment of area about x axis
Contribution of element a; Ixa = t  (DLt - t/2)3/12 + Aa  (D - t- (DLt - t/2)/2 - xbar)2 = 36.3 cm4
Contribution of element b; Ixb = Ab  (D-t- xbar)2 = 209.6 cm4
Contribution from element c; Ixc = t  (D - t)3/12 + Ac  ((D-t)/2 - xbar)2 = 191.1 cm4
Contribution from element d; Ixd = Ad  xbar2 = 209.6 cm4
Contribution of element e; Ixe = t  (DLb - t/2)3/12 + Ae  (xbar - (DLb - t/2)/2)2 = 36.3 cm4
Total second moment of area; Ixg = Ixa + Ixb + Ixc + Ixd + Ixe = ;682.9; cm4
Radius of gyration of gross cross section; rxg = (Ixg/Ag) = 78.43 mm
Position of y axis from centreline of web; ybar = [Aa  (Bt - t) + Ab  (Bt - t)/2 + Ad  (Bb - t)/2 + Ae  (Bb - t)]/Ag
ybar = 19.7 mm
Second moment of area about y axis
Contribution from element a; Iya = Aa  (Bt - t - ybar)2 = 11.9 cm4
Contribution from element b; Iyb = t  (Bt - t)3/12 + Ab  ((Bt - t)/2-ybar)2 = 15.1 cm4
Contribution from element c; Iyc = Ac  ybar2 = 22.8 cm4
Contribution from element d; Iyd = t  (Bb - t)3/12 + Ad  ((Bb - t)/2-ybar)2 = 15.1 cm4
Contribution from element e; Iye = Ae  (Bb - t - ybar)2 = 11.9 cm4
Total second moment of area; Iyg = Iya + Iyb + Iyc + Iyd + Iye = 76.9 cm4
Radius of gyration of gross cross section; ryg = (Iyg/Ag) = 26.32 mm

Element flat widths


Element a; ba = DLt - t - r = 12.9 mm
Element b; bb = Bt - 2  (t + r) = 68.8 mm
Element c; bc = D - 2  (t + r) = 193.8 mm
Element d; bd = Bb - 2  (t + r) = 68.8 mm
Element e; be = DLb - t - r = 12.9 mm
Steel details (Table 4)
;
Nominal yield strength; Ys = 450 N/mm2
Nominal ultimate tensile strength; Us = 480 N/mm2
Modified tensile yield strength due to cold forming (cl 3.4)
Average yield strength; Ysa = min(Ys + 5  N90  t2  (Us-Ys)/Ag, 1.25Ys, Us) = 454.9 N/mm2
Design strength in tension; pyt = min(Ysa, 0.84  Us) = 403.2 N/mm2
Modified compressive yield and design strengths due to cold forming (cl 3.4)
Yield strength element a; Ysaca = Ysa = 454.9 N/mm2;
Design strength element a; pyca = Ysaca = 454.9 N/mm2
Yield strength element b; Ysacb = Ys + (Ysa - Ys)  (48(280/Ys)0.5 - bb/t)/(24(280/Ys)0.5) = 453.8 N/mm2;
Design strength element b; pycb = Ysacb = 453.8 N/mm2
Yield strength element c; Ysacc = Ys = 450.0 N/mm2;
Design strength element c; pycc = Ysacc = 450.0 N/mm2
Yield strength element d; Ysacd = Ys + (Ysa - Ys)  (48(280/Ys)0.5 - bd/t)/(24(280/Ys)0.5) = 453.8 N/mm2;
Design strength element d; pycd = Ysacd = 453.8 N/mm2
Yield strength element e; Ysace = Ysa = 454.9 N/mm2
Design strength element e; pyce = Ysace = 454.9 N/mm2
Minimum modified compressive yield strength; Ysac = min(Ysaca, Ysacb, Ysacc, Ysacd, Ysace) = 450.0 N/mm2
Minimum design strength in compression; pyc = min(Ysac, 0.84  Us) = 403.2 N/mm2

Axial compression (Section 6)


Effective length for compression
Effective length about x axis; LEx = 9000 mm
Effective length about y axis; LEy = 9000 mm

Local buckling coefficients (fig. B.1)


Dimension b1; b1 = D - t = 197.0 mm
Dimension b2; b2 = B - t = 72.0 mm
Ratio of b2 to b1; h = b2 / b1 = 0.365
Element a; Ka_f = 0.425
Element b; Kb_f = max(4.0 , [7 - (1.8  h) / (0.15 + h) - 1.43  h3]  h2) = 4.000
Element c; Kc_f = max(4.0, 7 - (1.8  h) / (0.15 + h) - 1.43  h3) = 5.654
Element d; Kd_f = max(4.0 , [7 - (1.8  h) / (0.15 + h) - 1.43  h3]  h2) = 4.000
Element e; Ke_f = 0.425
Effective element widths
Element a (cl. 4.5.1)
Local buckling stress; pcra_f = 0.904  ES5950  Ka_f  (t / ba)2 = 4259.7 N/mm2
Basic effective width; ba_f_bas = ba[1+14((max(0.123,pyca/pcra_f))1/2-0.35)4]-0.2 = 12.9 mm
Actual effective width; ba_f = 0.89  ba_f_bas + 0.11  ba = 12.9 mm
Effective area; Aa_f = t  (ba_f + r + t / 2) = 43 mm2

Element b (cl. 4.4.1)


Local buckling stress; pcrb_f = 0.904  ES5950  Kb_f  (t / bb)2 = 1409.4 N/mm2
Effective width; bb_f = bb[1+14((max(0.123,pycb/pcrb_f))1/2-0.35)4]-0.2 = 68.4 mm
Effective area; Ab_f = t  (bb_f + 2  r + t) = 215 mm2

Element c (cl. 4.4.1)


Local buckling stress; pcrc_f = 0.904  ES5950  Kc_f  (t / bc)2 = 251.1 N/mm2
Effective width; bc_f = bc[1+14((max(0.123,pycc/pcrc_f))1/2-0.35)4]-0.2 = 113.7 mm
Effective area; Ac_f = t  (bc_f + 2  r + t) = 351 mm2

Element d (cl. 4.4.1)


Local buckling stress; pcrd_f = 0.904  ES5950  Kd_f  (t / bd)2 = 1409.4 N/mm2
Effective width; bd_f = bd[1+14((max(0.123,pycd/pcrd_f))1/2-0.35)4]-0.2 = 68.4 mm
Effective area; Ad_f = t  (bd_f + 2  r + t) = 215 mm2

Element e (cl. 4.5.1)


Local buckling stress; pcre_f = 0.904  ES5950  Ke_f  (t / be)2 = 4259.7 N/mm2
Basic effective width; be_f_bas = be[1+14((max(0.123,pyce/pcre_f))1/2-0.35)4]-0.2 = 12.9 mm
Actual effective width; be_f = 0.89  be_f_bas + 0.11  be = 12.9 mm
Effective area; Ae_f = t  (be_f + r + t / 2) = 43 mm2

Total effective area


Total effective area; Af = Aa_f + Ab_f + Ac_f + Ad_f + Ae_f = 867 mm2
Position of y axis of effective area from web; yf = [Aa_f(B-t) + Ab_f(B-t)/2 + Ad_f(B-t)/2 + Ae_f(B-t)] / Af = 25.1 mm
Dist. between gross and effective area y axes; es = yf - ybar = 5.4 mm; (Generating a +ve moment);
Torsional flexural buckling capacity (cl 6.3 & annex D)
Dimension b (Table D.1); b = B - t = 72.0 mm
Dimension d (Table D.1); d = D - t = 197.0 mm
Dimension bL (Table D.1); bL = DLt - t / 2 = 14.5 mm
Position of shear centre (Table D.1); e = d2  b  bL  t  [1/2 + b / (4bL) - 2bL2 / (3d2)] / Ixg = 30.9 mm
Warping constant (Table D.1); Cw = b2  t  [4  bL3 + 3  d2  bL - 6  d  bL2 + b  d2] / 6 - Ixg  e2
Cw = 4472.3 cm6
St. Venant torsion constant; J = [(bat3) + (bbt3) + (bct3) + (bdt3) + (bet3)]/3 = 3214.800 mm4
Distance from shear ctr to centroid (along x axis); xo = ybar + e = 50.6 mm
Polar radius of gyration; ro = (rxg2 + ryg2 + xo2)1/2 = 97.0 mm
Beta constant;  = 1 - (xo/ro)2 = 0.728
Short strut capacity; Pcs = Af  pyc = 349.7 kN
Torsional buckling load; PT = min(Pcs, 1/ ro2  (GS5950  J + 2  2  ES5950  Cw/max(LEx,LEy)2))
PT = 50.7 kN
Elastic flexural buckling load (x axis); PEx = min(Pcs, 2  ES5950  Ixg / LEx2) = 170.6 kN
Torsional flexural buckling load; PTF = min(Pcs, 1/(2)  [(PEx+PT) - ((PEx+PT)2 - 4PExPT)1/2])
PTF = 46.1 kN
Elastic flexural buckling load (y axis); PEy = min(Pcs, 2  ES5950  Iyg / LEy2) = 19.2 kN
Slenderness ratio factor (x axis); x = max(1.0, (PEx / PTF)1/2) = 1.92
Slenderness ratio factor (y axis); y = max(1.0, (PEy / PTF)1/2) = 1.00

Flexural buckling capacity (cl 6.2)


Slenderness ratio (x axis); x = x  LEx/rxg = 220.8
Slenderness ratio (y axis); y = y  LEy/ryg = 342.0
The section slenderness is adequate for compression loads due to wind reversal only;
Short strut capacity; Pcs = Af  pyc = 349.7 kN
Perry coefficient (x axis); x = 0.002  (x  LEx/rxg - 20) = 0.402;
Constant phi (x axis); x = [Pcs + (1+x)  PEx]/2 = 294.4 kN
Flexural buckling load (x axis); Pcx = PEx  Pcs/[x + (x2 - PExPcs)] = 130.0 kN
Perry coefficient (y axis); y = 0.002  (y  LEy/ryg - 20) = 0.644;
Constant phi (y axis); y = [Pcs + (1+y)  PEy]/2 = 190.6 kN
Flexural buckling load (y axis); Pcy = PEy  Pcs/[y + (y2 - PEyPcs)] = 18.5 kN
Minimum flexural buckling load; Pc = min(Pcx, Pcy) = 18.5 kN
PASS - Pc >= F - Axial load capacity is adequate (UF = 0.054)
Applied moment due to shift in neutral axis; Mys = F  es = 0.0 kNm
Modified positive design moment; Myp = Myp + Mys = ;0.3; kNm
Myp>0 kNm - Therefore there is a resultant positive moment
Modified negative design moment; Myn = Myn + Mys = ;-0.5; kNm
Myn<0 kNm - Therefore there is a resultant negative moment

Major axis bending


;
Limiting web stress (cl. 5.2.2.2)
Depth of compression zone; Dc = (D - t) / 2 = 98.5 mm
Depth Dw; Dw = max(D, 2  Dc) = 200.0 mm
Limiting web stress; p0 = min[(1.13 - 0.0019  Dw (Ysac / 280 N/mm2)0.5/ t)  pyc ,pyc]
p0 = 390.9 N/mm2
Element effective widths
Element a (cl. 4.5.2)
Stress at supported edge; fcs = p0 = 390.9 N/mm2
Stress at free edge; fcf = p0  2  (D / 2 - DL) / (D - t) = 333.3 N/mm2
Ratio of fcs to fcf; R = fcs / fcf = 1.173
Local buckling coefficient; Ka_mx = max(0.425, 1.7 / (3 + R)) = 0.425
Local buckling stress; pcra_mx = 0.904  ES5950  Ka_mx  (t / ba)2 = 4259.7 N/mm2
Compressive stress; fca_mx = fcf = 333.3 N/mm2
Basic effective width; ba_mx_bas = ba[1+14((max(0.123,fca_mx/pcra_mx))1/2-0.35)4]-0.2 = 12.9 mm
Actual effective width; ba_mx = 0.89  ba_mx_bas + 0.11  ba = 12.9 mm

Element b (cl. 4.4.1)


Dimension b1; b1 = B - t = 72.0 mm
Dimension b2; b2 = D - t = 197.0 mm
Ratio of b2 to b1; h = b2 / b1 = 2.736
Local buckling coefficient (fig. B.2); Kb_mx = max(4.0, 5.4 - (1.4  h) / (0.6 + h) - 0.02  h3) = 4.000
Local buckling stress; pcrb_mx = 0.904  ES5950  Kb_mx  (t / bb)2 = 1409.4 N/mm2
Compressive stress; fcb_mx = p0 = 390.9 N/mm2
Effective width; bb_mx = bb[1+14((max(0.123,fcb_mx/pcrb_mx))1/2-0.35)4]-0.2 = 68.6 mm

Effective section properties


Effective area of element a; Aa_mx = (ba_mx + r +t / 2)  t = 43 mm2
Effective area of element b; Ab_mx = (bb_mx + 2  r + t)  t = 215 mm2
Total effective area; Amx = Aa_mx+Ab_mx + Ac + Ad + Ae = ;1109; mm2
Position of neutral axis from tension flange ctrline; xmx = [Aa_mx(D-t-(t/2+r+ba_mx)/2)+Ab_mx(D-t)+Ac(D-t)/2+Ae(DL-
t/2)/2]/Amx =
xmx = 98.5 mm
Second moment of area about neutral axis
Contribution from element a; Ia_mx = t  (t/2 + r + ba_mx)3 / 12 + Aa_mx  (D - t - (t/2 + r + ba_mx)/2 - xmx)2
Ia_mx = 36.3 cm4
Contribution from element b; Ib_mx = Ab_mx  (D - t - xmx)2 = 209.2 cm4
Contribution from element c; Ic_mx = t  (D - t)3/12 + Ac  ((D - t)/2 - xmx)2 = 191.1 cm4
Contribution from element d; Id_mx = Ad  xmx2 = 209.4 cm4
Contribution from element e; Ie_mx = t  (DL - t/2)3/12 + Ae  ((DL - t/2)/2 - xmx)2 = 36.3 cm4
Total second moment of area; Imx = Ia_mx + Ib_mx + Ic_mx + Id_mx + Ie_mx = ;682.3; cm4
Section modulus (compression edge); Zxc = Imx / (D - t - xmx) = 69.2 cm3
Section modulus (tension edge); Zxt = Imx / xmx = 69.3 cm3
Moment capacity
Stress at tension flange; p0t = p0  xmx / (D - t - xmx) = 390.5 N/mm2
Moment capacity at tension face; Mcxt = p0t  Zxt = 27.06 kNm
Moment capacity at compression face; Mcxc = p0  Zxc = 27.06 kNm
Moment capacity; Mcx = min(Mcxt, Mcxc) = 27.06 kNm
PASS - The moment capacity exceeds the applied moment
Shear in web (cl. 5.4)
Applied shear force; Fvy = 0.33 kN
Maximum applied shear stress; vmax_y = Fvy(B-t/2)(D-t)(1+(D-t)/(4(B-t/2)))/(2Ixg) = ;0.58; N/mm2
Maximum allowable shear stress; pv_max = 0.7  py = 282.24 N/mm2
Average shear stress; vy = Fvy / (t  D) = ;0.55; N/mm2
Shear yield strength; pv = 0.6  py = 241.92 N/mm2
Shear buckling strength; qcry = (1000  t / D)2  1.0 N/mm2 = 225.00 N/mm2
Minimum shear strength; pvy_min = min(pv , qcry) = 225.00 N/mm2
PASS - The shear capacity is not exceeded
Combined bending and shear (cl. 5.5.2)
Shear/shear buckling resistance; Pvy = min(pv , qcry)  D  t = ;135.00; kN
Bending moment at position of max shear; Mvx = 0.51 kNm
Section utilisation; UFvy1 = (Fvy / Pvy)2 + (Mvx / Mcx)2 = 0.000
PASS - The section utilisation is less than 1.0
Shear force at position of max moment; Fvy_m = 0.3 kN
Section utilisation; UFvy2 = (Fvy_m / Pvy)2 + (Mx / Mcx)2 = 0.735
PASS - The section utilisation is less than 1.0

Minor axis positive bending capacity


Limiting web stress (cl. 5.2.2.2)
Depth of compression zone; Dc = ybar = 19.7 mm
Depth Dw; Dw = max(B , 2  Dc) = 75.0 mm
Limiting web stress; p0 = min[(1.13 - 0.0019  Dw (Ysac / 280 N/mm2)0.5/ t)  pyc ,pyc]
p0 = 403.2 N/mm2
Element effective widths
Element c (cl. 4.4.1)
Dimension b1; b1 = D - t = 197.0 mm
Dimension b2; b2 = B - t = 72.0 mm
Ratio of b2 to b1; h = b2 / b1 = 0.365
Local buckling coefficient (fig. B.2); Kc_my = max(4.0, 7 - (1.8  h) / (0.15 + h) - 0.091  h3) = 5.719
Local buckling stress; pcrc_my = 0.904  ES5950  Kc_my  (t / bc)2 = 254.0 N/mm2
Compressive stress; fcc_my = p0 = 403.2 N/mm2
Effective width; bc_my = bc[1+14((max(0.123,fcc_my/pcrc_my))1/2-0.35)4]-0.2 = 120.9 mm

Effective section properties


Effective area of element c; Ac_my = (bc_my + 2  r +t)  t = 372 mm2
Total effective area; Amy = Aa + Ab + Ac_my + Ad + Ae = 891 mm2
Position of neutral axis from comp flange ctrline; ymy=[Aa(B-t) + Ab(B-t)/2 + Ad(B-t)/2 + Ae(B-t)]/Amy = 24.5 mm
Stress at tension flange; p0t = p0  (B - t - ymy) / ymy = 782.7 N/mm2
The elastic value of p0t exceeds pyt therefore, in accordance with clause 5.2.2.1, allow for plastic redistribution of tensile
stresses with a limiting value of pyt.
Let the distance from the compression flange to the neutral axis equal yp, then:-
Compression force; C = p0  Ac_my + p0  t  yp
Tension force; T = pyt(Aa + Ae) + 2pytt[B - t - yp  (1 + pyt/p0)] + (pyt2/p0)  t  yp
Equating compression and tension force and solving for yp:-
Distance from compression flange to N.A.; yp = 12.2 mm
Compression force; C = p0  Ac_my + p0  t  yp = 164.9 kN
Tension force; T = pyt(Aa + Ae) + 2pytt[B - t - yp  (1 + pyt/p0)] + (pyt2/p0)  t  yp
T = 164.9 kN
Taking moments about neutral axis:-
Moment due to compression force; Mcf = p0  Ac_my  yp + 2  p0  t  yp2 / 3 = 1.96 kNm
Mt due to tension force (elements a and e); Mtf1 = pyt(Aa + Ae)  (B - t - yp) = 2.10 kNm
Mt due to tension force (elmts b and d, stress pyt); Mtf2 = 2pytt[B-t-yp(1 + pyt/p0)]  [B-t-yp-(B-t-yp(1 + pyt/p0))/2]
Mtf2 = 4.14 kNm
Mt due to ten force (elmts b and d, varying stress); Mtf3 = 2  (pyt2/p0)  t  yp2 (pyt/p0) / 3 = 0.12 kNm
Positive moment capacity; Mcyp = Mcf + Mtf1 + Mtf2 + Mtf3 = 8.31 kNm
Positive bending section utilisation; UFMyp = Myp/Mcyp = 0.034
Pass - Mcyp >= Myp - Positive y axis bending capacity is adequate (UF = 0.034)

Minor axis negative bending capacity


Limiting web stress (cl. 5.2.2.2)
Depth of compression zone; Dc = B - t - ybar = 52.3 mm
Depth Dw; Dw = max(B , 2  Dc) = 104.7 mm
Limiting web stress; p0 = min[(1.13 - 0.0019  Dw (Ysac / 280 N/mm2)0.5/ t)  pyc ,pyc]
p0 = 403.2 N/mm2
Element effective widths
Element a (cl. 4.5.1)
Local buckling coefficient; Ka_my = 0.425
Local buckling stress; pcra_my = 0.904  ES5950  Ka_my  (t / ba)2 = 4259.7 N/mm2
Compressive stress; fca_my = p0 = 403.2 N/mm2
Basic effective width; ba_my_bas = ba[1+14((max(0.123,fca_my/pcra_my))1/2-0.35)4]-0.2 = 12.9 mm
Actual effective width; ba_my = 0.89  ba_my_bas + 0.11  ba = 12.9 mm

Element e (cl. 4.5.1)


Local buckling coefficient; Ke_my = 0.425
Local buckling stress; pcre_my = 0.904  ES5950  Ke_my  (t / be)2 = 4259.7 N/mm2
Compressive stress; fce_my = p0 = 403.2 N/mm2
Basic effective width; be_my_bas = be[1+14((max(0.123,fce_my/pcre_my))1/2-0.35)4]-0.2 = 12.9 mm
Actual effective width; be_my = 0.89  be_my_bas + 0.11  be = 12.9 mm

Effective section properties


Effective area of element a; Aa_my = (ba_my + r +t / 2)  t = 43 mm2
Effective area of element e; Ae_my = (be_my + r +t / 2)  t = 43 mm2
Total effective area; Amy = Aa_my + Ab + Ac + Ad + Ae_my = 1110 mm2
Position of neutral axis from tension flange ctrline; ymy = [Aa_my(B-t) + Ab(B-t)/2 + Ad(B-t)/2 + Ae_my(B-t)] / Amy
ymy = 19.7 mm
Stress at tension flange; p0t = p0  ymy / (B - t - ymy) = 151.4 N/mm2
Second moment of area about neutral axis
Contribution from element a; Ia_my = Aa_my  (B - t - ymy)2 = 11.9 cm4
Contribution from element b; Ib_my = t  (B - t)3/12 + Ab  ((B - t)/2 - ymy)2 = 15.1 cm4
Contribution from element c; Ic_my = Ac  ymy2 = 22.8 cm4
Contribution from element d; Id_my = t  (B - t)3/12 + Ad  ((B - t)/2 - ymy)2 = 15.1 cm4
Contribution from element e; Ie_my = Ae_my  (B - t - ymy)2 = 11.9 cm4
Total second moment of area; Imy = Ia_my + Ib_my + Ic_my + Id_my + Ie_my = 76.9 cm4
Section modulus (compression edge); Zyc = Imy / (B - t - ymy) = 14.7 cm3
Section modulus (tension edge); Zyt = Imy / ymy = 39.1 cm3
Moment capacity
Moment capacity at tension face; Mcynt = p0t  Zyt = 5.92 kNm
Moment capacity at compression face; Mcync = p0  Zyc = 5.92 kNm
Negative moment capacity; Mcyn = min(Mcynt, Mcync) = 5.92 kNm
Negative bending section utilisation; UFMyn = abs(Myn)/Mcyn = 0.085
Pass - Mcyn >= Myn - Negative y axis bending capacity is adequate (UF = 0.085)
Shear in web (cl. 5.4)
Applied shear force; Fvx = 4.00 kN
Maximum applied shear stress; vmax_x = Fvx  ((B - t/2) - ybar)2 / Iyg = 15.09 N/mm2
Maximum allowable shear stress; pv_max = 0.7  py = 282.24 N/mm2
Average shear stress; vx = Fvx / (2  t  B) = 8.89 N/mm2
Shear yield strength; pv = 0.6  py = 241.92 N/mm2
Shear buckling strength; qcrx = (1000  t / B)2  1.0 N/mm2 = 1600.00 N/mm2
Minimum shear strength; pvx_min = min(pv , qcrx) = 241.92 N/mm2
PASS - The shear capacity is not exceeded
Combined bending and shear (cl. 5.5.2)
Shear/shear buckling resistance; Pvx = min(pv , qcrx)  2  B  t = 108.86 kN
Bending moment at position of max shear; Mvy = 0.00 kNm
Section utilisation; UFvx1 = (Fvx / Pvx)2 + (Mvy / Mcyp)2 = ;0.001
PASS - The section utilisation is less than 1.0
Shear force at position of max positive moment; Fvx_mp = 0.0 kN
Section utilisation; UFvx2 = (Fvx_mp / Pvx)2 + (Myp / Mcyp)2 = 0.001
PASS - The section utilisation is less than 1.0
Shear force at position of max negative moment; Fvx_mn = 0.0 kN
Section utilisation; UFvx3 = (Fvx_mn / Pvx)2 + (Myn / Mcyn)2 = 0.007
PASS - The section utilisation is less than 1.0

Combined bending and compression


Local capacity check (cl. 6.4.2)
Section utilisation (-ve My critical); UFlocal = F / Pcs + Mx / Mcx + abs(Myn) / Mcyn = 0.945
Pass - Local compression and bending capacity is adequate (UF = 0.945)
Overall buckling capacity check (cl. 6.4.3)
Section utilisation (-ve My critical); UFo_all1 = F/Pc + Mx/[CbxMcx(1-F/PEx)] + abs(Myn)/[CbyMcyn(1-F/PEy)]
UFo_all1 = 0.968
Pass - Overall buckling capacity is adequate (UF = 0.968)

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