Numerical Investigation of the Dynamic Behavior of 2D Steel Structures with CFST Columns in Seismic Zones

Concrete-filled Hollow Rectangular Section Columns (RHS-CFST) are widely used in steel structures in seismic zones due to their ductility, energy dissipation, and load-bearing capacity. This study investigates the seismic response of structures with I-beam to RHS-CFST column connections in compliance with the Algerian seismic code, RPA 99/2003. The dynamic response of a 9-story steel structure is analyzed, examining the impact of CFST columns, building height, and connection types. Results indicate that CFST columns exhibit symmetrical behavior under seismic loading, which effectively reduces base shear forces and minimizes inter-story drift. Despite their semi-rigid nature, these columns demonstrate high energy dissipation, significant ductility, and a broad hysteresis loop, ensuring structural resilience and safety. As the Algerian code currently lacks specific provisions for this structural type, this study provides critical insights to advance seismic performance parameters for steel structures that incorporate CFST columns.