# Weld group capacity (elastic method)

Calculate the capacity of a weld group using the elastic stress method

## Input:

kip-ft
kips
kips
kip-ft
in
in ## Output:

1. Definitions
• ϕw = Resistance factor for welds
• Mu = Factored moment (kip*ft)
• Nu = Axial load; Tension positive (kip)
• Tu = Factored torsional moment (kip-ft)
• Vu = Factored shear force (kip)
• b = weld group width (in)
• d = weld group depth, height, or diameter (in)
• r = distance from centroid to weld, for calculating torsion stress (in)
• fRu = resultant stress (kip / in)
2. Calculate the geometric properties of the weld group
• yc = d / 2 = 12 in
• J = (b+d)3 / 6 = 7776 in3
• Scx = bd + d2/3 = 480 in2
• Aw = 2d + 2b = 72 in
• rmax = Sqrt((b/2)2+(d/2)2) = 13.416 in
3. Calculate the unit stress from each applied load
• fPu = Nu/Aw = 0 kip / 72 in = 0 kip/in
• fVu = Vu/Aw = 0 kip / 72 in = 0 kip/in
• fMu = Mu/Sxx = 0 kip-in / 480 in2 = 0 kip/in
• fTu,max = Tu rmax / J = 0 kip-in / 7776 in2 = 0 kip/in
4. Calculate the peak resultant stress using vector combination
• Note: fTu added to fVu (assumed to act in same direction)
• fRu = sqrt([fTu + fMu]2 + [fVu + fTu]2 ) = 0
5. Calculate the required weld size
• Use weld with strength of 0 kip/in