Seismic Performance of Steel Structures with Base-Hinged Columns Under Rigidly and Flexibly Braced Systems

Steel structures with base-hinged columns are one of the typical forms adopted for rural housing in villages and towns due to their superior seismic resistance, energy efficiency, and environmental benefits. The lateral bracing system plays a crucial role in the ability of steel frames with base-hinged columns to resist horizontal forces. This study investigates the impact of rigid and flexible bracing on the seismic performance of such structures, emphasizing that enhanced ductility—particularly in flexibly braced frames—is essential for seismic resilience in earthquake-prone areas. Two full-scale steel frame models, one with rigid bracing and the other with flexible bracing, were fabricated based on typical rural housing designs and subjected to low-cycle reversed loading tests. The results indicate that the rigidly braced frame undergoes brittle failure, characterized by fractures and buckling at bracing intersections. In contrast, the flexibly braced frame exhibits ductile failure, identified by the bending deformation of tension rods. Despite the flexibly braced frame reaching a peak-load bearing capacity that is only 69.1% (positive direction) and 76.0% (negative direction) of the rigidly braced frame, it achieves ultimate displacements 2.7 times (positive direction) and 2.5 times (negative direction) greater. Additionally, the flexibly braced frame exhibits a stable energy dissipation capacity, with cumulative energy dissipation 1.49 times that of the rigidly braced frame. Numerical simulations were conducted to develop finite element models for both rigidly and flexibly braced frames. The resulting failure characteristics and bearing capacities of the frames were obtained, providing further validation of the experimental results. These findings provide data-supported evidence for promoting steel structures with base-hinged columns in rural housing applications.