Eccentric Fillet Weld Group (Elastic Method)
Line polar moment, direct shear, torsional components, the resultant unit force at the critical corner.
Example
You enter
- In-plane load P (lb) 12000
- Eccentricity from centroid (in) 6
- Length of each vertical weld (in) 10
- Separation between welds (in) 4
- Allowable per 1/16 in leg (lb/in) 928
You get
- Line polar moment J 246.7 in3
- Direct shear 600 lb/in
- Resultant at critical corner 1879 lb/in
- Required fillet leg 3
Details, formula, and sources
Line polar moment, direct shear, torsional components, the resultant unit force at the critical corner, and the required fillet leg for two vertical welds under in-plane eccentric load by the AISC elastic (vector) method. The conservative elastic method, a screen; the engineer of record governs.
Two vertical welds length D, separation B: L_w = 2D; Ix = D3/6; Iy = D B2/2; J = Ix + Iy; direct shear f_d = P/L_w; torque T = P x e; f_tx = T(D/2)/J; f_ty = T(B/2)/J; resultant f_r = sqrt(f_tx2 + (f_d + f_ty)2); required leg (sixteenths) = ceil(f_r / allowable per 1/16 in).
Eccentrically loaded fillet weld group, elastic (vector) method, per AISC 360 and the AISC Steel Construction Manual Part 8, by name.
First-principles weld-line mechanics (the elastic method); the load, eccentricity, weld geometry, and the E70 allowable (about 928 lb/in per 1/16 in, ASD) are user-supplied.
Estimate. Engineer of record governs the design and acceptance. Verify against the project structural drawings and the manufacturer's published capacity / chart.
Field names used by the API: load_lb, ecc_in, weld_len_in, separation_in, allow_per_16, polar_moment_in3, direct_shear_lb_in, resultant_lb_in, req_leg_16
- Fillet allowable E70 ASD about 928 lb/in per 1/16 in of leg; editableAISC 360 §J2
- Method elastic (vector) method, conservative vs instantaneous-centerAISC Manual Part 8