In‐plane behavior of a cold‐formed steel frame built with box section elements

Abstract The Latin American Pacific coast is located in a high seismic risk zone and unfortunately, it has vulnerable housing built without control or compliance with seismic regulations. This study focuses on a common housing typology in Ecuador and Colombia, which is constructed using cold‐formed steel (CFS) elements. This experimental investigation assesses the structural response of moment‐resistant frames constructed from CFS components. Two full‐scale specimens were tested: simple portal frames (BF‐1 and BF‐2), each built with a one‐story and single‐span configuration. These samples were subjected to quasistatic lateral load with one experiencing monotonic loading and the other cyclic loading. A vertical load of 15 kN was applied to simulate slab load. Laboratory testing revealed concentrated damage at the connection with the beam. Additionally, specimen BF‐2 showed a small crack in the weld. The study provides a detailed analysis of the lateral load–displacement response curve, ultimate resistance, ductility factor, and failure modes. Four methodologies (AISI 400, ASCE/SEI 41, ATC‐24, and OA) were used to determine the characteristic points of structural response curves. Despite differing loading conditions, both samples exhibit similar structural performance. This research reveals that these frames could develop an inelastic performance as they present an overall ductility coefficient of 2.17.