Evaluation of optimal alternative between LSF, CFS, and conventional steel structures

Several techniques have been used for further seismic retrofitting of structures in recent years. Light steel frame (LSF) and cold-formed steel (CFS) structural systems are effective seismic performance improvement approaches. LSF and CFS systems receive small lateral loads during major earthquake events and have been widely used for construction across the world due to their prefabricated structural members, lightweight components, rapid construction, and excellent thermal insulation. This study evaluated and compared the behavior of LSF and CFS to hot-rolled steel moment-resisting frames (MRFs). Models were designed in SAP 2000 via the existing code provisions and extensive reports on the CFS, LSF, and MRF structures. The models were validated and imported to OpenSEES for further analysis on two-, three-, and 4-story frames. Modal and linear analysis revealed that CFS and LSF structures had a larger base shear than MRF, with the CFS frame showing the highest base shear (approximately 30 % greater than MRF) due to its high stiffness and low ductility. Pushover analysis showed that MRF had significantly higher stiffness and strength than CFS and LSF, with MRF up to six times stronger than LSF. CFS outperformed LSF in all cases. While MRF resisted higher loads, CFS and LSF exhibited better energy dissipation. Additionally, nonlinear time-history analysis showed that CFS and LSF systems had larger maximum drifts than MRF, with CFS outperforming LSF in seismic stability. However, in terms of residual drift, LSF and CFS performed significantly better than MRF, indicating improved re-centering capability. The LSF and CFS systems were also preferential over the MRF in terms of structural mass.