Seismic behavior of a large-scale composite MRF system with CFT columns

An experimental study on the seismic behavior of a composite moment resisting frame (MRF) with concrete filled steel tubular (CFT) columns was conducted at the ATLSS Engineering Research Center, located at Lehigh University. The objective of this study was to investigate the seismic performance of composite MRFs with CFT columns. The test structure in the study represented a three-fifths scale model of a perimeter MRF in a five-story prototype building. The MRF was composed of CFT columns and steel wide-flange beams, where the beam-to-column moment connections were split-tee connections. The study involved subjecting the test structure to three different seismic hazard levels: frequent occurrence (FOE), design basis (DBE), and maximum considered (MCE) earthquake. The structure was designed to sustain minor yielding during the FOE event, exhibit no strength degradation during the DBE event, and avoid collapse during the MCE level event. The structure performance under the simulated earthquake excitations was observed to be consistent with the expected performance for all the hazard levels, indicating that composite MRFs with CFT columns can be effectively used to resist seismic loading conditions.