Capacity Evaluation of Unequal-Leg Single-Angle Steel Compression Members using Indian and American Code Provisions

Objectives: This study aims to compare the design strength of eccentrically loaded unequal leg single angles under compression according to IS 800:1984, IS 800:2007, IS 800:2007 (Amendment 2), and AISC 360-22 Specifications for structural steel buildings. Methods: Spreadsheets were developed to evaluate the compression capacities of unequal single-angle sections using all these codes. The analysis focused on unequal leg single angle connected by either longer or shorter legs, under eccentric loading conditions. Findings: IS 800:2007 (Amendment 2) significantly enhances the compression strength of unequal leg single angles compared to IS 800:2007, with increases of up to 40% for angles fastened through the longer leg and up to 87% for those fastened through the shorter leg. Compared to the AISC 360-22 LRFD method, IS 800:2007 (Amendment 2) provides up to 184% more strength for angles fastened through the longer leg and up to 179% more for angles fastened through the shorter leg, While IS 800:2007 provides up to 112% more strength for angles connected by the longer leg and up to 68% more for those connected by the shorter leg. IS 800:1984 also shows increased strength over the AISC 360-22 ASD method, with up to 67% more strength for angles connected by the longer leg and 27% more for those attached by the shorter leg. Additionally, IS 800:2007 (Amendment 2) reveals that unequal leg single angles connected by the shorter leg provide up to 56% more compression strength than those connected by the longer leg. Novelty: This research compares the capacity predicted by the latest amendment of the Indian standard code for steel design with its previous versions and the American code, focusing on the design of unequal-legged single-angle compression members. It offers valuable insights into the capacity prediction and overall structural safety, and thereby the resulting economy in the choice of steel sections. An important insight from the study is that unequal leg single angles connected by the shorter leg exhibit greater compression strength than those connected by the longer leg. Keywords: Unequal legs, Eccentrically loaded, Single angles, Steel sections, Indian codes, American codes