Strength Coefficients for Eccentrically Loaded Weld Groups

Abstract

When AISC Manual Tables 8-4 through 8-11 are used to calculate the strength of eccentrically loaded weld groups with F_EXX ≠ 70 ksi, the values are multiplied by an electrode strength coefficient, C₁. The C₁ values are dependent on the filler metal classification strength; however, they are not proportional to the filler metal classification strength ratio when F_EXX ≥ 80 ksi. To consider the potential effect of reduced ductility, the C₁ values include reduction factors of 0.85 and 0.90 for higher-strength welds.
To investigate the accuracy of the electrode strength coefficients, the ductility of high-strength welds was evaluated using the data from 93 experimental tests from three existing research projects with F_EXX > 70 ksi. The data was used to plot the weld metal tensile strength versus the normalized rupture deformation of both longitudinal and transverse fillet welds. The analysis showed that, when F_EXX ≤ 120 ksi, the C₁ values can be based solely on the filler metal classification strength ratio, F_EXX/70 ksi, without the reduction factors of 0.85 and 0.90 for higher-strength welds.