Predetermined Collector Force and Rotation Histories Tests on TFW, in Advancing Knowledge on the Performance of Seismic Collectors in Steel Building Structures

Predetermined collector force history tests were conducted on a Top Flange Weld (TFW) collector connection to evaluate its performance under different levels of seismic hazard loading. A test collector specimen with a TFW connection was designed, fabricated, and experimentally evaluated under prescribed seismic collector force and inter-story drift histories, without composite slab or gravity loading. The TFW collector connection demands were obtained from nonlinear time-history analyses of archetype steel buildings. Based on these analyses, representative collector force and story drift demands were selected for the test specimen. Snippets of the loading histories corresponding to different seismic hazard levels were extracted, and each loading history was subdivided as necessary based on force and rotation increments. The selected snippet histories of drift and collector force were applied consecutively. For each loading step, the reaction column was first rotated to the target drift using reaction actuators, followed by application of the corresponding collector force through the loading actuators. This procedure was repeated sequentially until completion of the selected snippet. These tests provide insight into the performance of the TFW collector connection under seismic load demands associated with different earthquake hazard levels.