Performance Assessment of BRB Inverted-V Bracing Systems with Zipper Columns under Sequential Earthquakes

Due to the continuous decrease in global energy resources, the science of structural retrofitting has become one of the most important research fields in structural engineering. Retrofitting is considered a practical and economical solution to improve the performance of existing deficient buildings without the need for demolition and reconstruction, thereby saving time, cost, and energy. In this study, considering the wide application of concentrically braced frame (CBF) systems in Iran, the seismic retrofitting of buildings with this structural system is investigated using the zipper column concept. The use of zipper columns in chevron (inverted-V) bracing systems improves the well-known weakness of chevron-braced frames, namely local buckling and yielding concentration in beams, which results in excessive lateral deformations. To evaluate the seismic performance improvement, three buildings with ۵, ۱۰, and ۱۵ stories were modeled and analyzed under three earthquake ground-motion records using nonlinear time-history analysis in SAP۲۰۰۰. The results indicate the poor seismic performance of the original braced frames compared to the retrofitted systems. Implementation of the zipper column significantly reduced plastic hinge formation and inter-story drifts, improved performance levels, and enhanced the energy dissipation capacity of the structures under earthquake loading. Overall, the retrofitted systems exhibited more stable and desirable seismic behavior

کلیدواژه ها:

Zipper Column ، Nonlinear Time-History Analysis ، Structural Energy Dissipation ، Lateral Displacement ، Buckling-Restrained Braced Frames