Experimental and analytical fragility assessment of a combined heavy timber–steel‐braced frame through hybrid simulation

Summary A combined heavy timber–steel structural system has recently been developed for the adaptation of advanced structural braces into tall timber structures. This study investigates the system‐level performance of a seven‐story combined timber–steel friction‐braced frame using hybrid simulation and incremental dynamic analysis (IDA). The IDA results from the hybrid simulations are compared with a numerical model to assess its ability to capture the nonlinear seismic performance of the timber–steel friction‐braced frame. Experimental and numerical IDA results are used to derive fragility curves for interstory and residual drift and assess its collapse probability under different earthquake hazard levels. The hybrid test results show that the timber–steel friction‐braced frame demonstrates excellent seismic performance under a range of ground motion intensities. The experimental results from the hybrid simulations and the experimental fragility curves correlate well with the numerical modeling results.