Seismic performance assessment of conventional CLT shear wall structures and post-tensioned CLT shear wall structures

This paper presents the performance-based seismic assessment framework on conventional CLT shear wall structures (C-CLTStrs) and post-tensioned CLT shear wall structures (PT-CLTStrs). Numerical models of both the conventional CLT shear walls and the PT CLT shear walls were developed and calibrated with experimental results. A direct displacement-based design (DDD) procedure was then developed and demonstrated by the design examples of one 8-storey C-CLTStr and a set of 8-, 12-, and 16-storey PT-CLTStrs. Corresponding simplified structural models were developed. A series of pushover and time-history dynamic analysis was conducted afterwards to calibrate the calculated structural performance objectives with the design targets of the DDD procedure. Finally, using 50 mainshock (MS) and 50 mainshock-aftershock (MSAS) earthquake records, probability seismic demanding analysis (PSDA) were conducted to evaluate two engineering demanding parameters of the structures, namely the maximum inter-storey drift (MaxISDR) and the residual inter-storey drift (ResISDR). The MaxISDR limit states of the PT-CLTStrs are recommended at 0.7%, 1.4%, and 2.2% for the immediate occupancy (IO), life safety (LS), and collapse prevention (CP) hazard levels, respectively. The MaxISDR of the PT-CLTStrs is almost twice that of the C-CLTStrs, while the ResISDR is at most 50% of that of the C-CLTStrs. The damage probability of the 8-storey PT-CLTStr indicated by ResISDR is not significantly sensitive to the consideration of aftershocks seismic input, whereas, when aftershocks are considered, up to a 7.0% difference under the LS hazard level is caused in the damage probability of the 8-storey C-CLTStr indicated by ResISDR.