Seismic assessment of semi-rigid steel frame structures incorporating chevron-zipper bracing under near-fault ground motions using opensees

This study presents a comprehensive seismic evaluation of steel frame structures with semi-rigid connections integrated with Chevron-Zipper bracing systems under near-fault earthquake excitations using OpenSees. The research aims to enhance the seismic resilience of such frames by mitigating lateral deformations and structural damage. Three archetypal models representing low-rise (5-story), mid-rise (8-story), and high-rise (12-story) buildings were developed, incorporating both pinned and semi-rigid (ductile) connections. A total of 84 structural configurations were subjected to dynamic nonlinear time history analyses using seven near-fault ground motion records. Comparative assessments were conducted for frames with and without zipper columns. Results indicate that the addition of zipper columns significantly improves seismic performance by reducing inter-story drifts and peak lateral displacements, particularly in frames with ductile connections. These findings underscore the effectiveness of the Chevron-Zipper bracing configuration in enhancing structural performance against near-fault seismic events.