Evaluation of engineering demand parameters for seismic analyses of CLT-glulam hybrid structures

Abstract

By bracing glulam frames with cross-laminated timber (CLT) shear walls, CLT-glulam hybrid structures offer a promising solution for multi-story timber construction. This paper presents an assessment of engineering demand parameters (EDPs) for seismic analyses of such hybrid structures. Five EDPs were considered, including the commonly used maximum inter-story drift ratios (MaxISDRs), peak floor accelerations (PFAs), and maximum roof drift ratios (MaxRDRs), as well as two newly developed EDPs named maximum connection damage index (MaxCDI) and maximum inter-story CLT shear wall damage index (MaxISWDI). The EDPs were assessed through nonlinear time-history analyses (NLTHAs) on 12 prototype CLT-glulam hybrid structures with different building heights, construction types of CLT shear wall subsystems (platform or balloon), and inter-story configurations of CLT shear walls. The MaxCDI was then employed as the benchmark EDP to evaluate the effectiveness of the other four EDPs in capturing structural damage. The results showed that the connection damage of glulam frame subsystems was limited during major earthquakes, and the construction type of CLT shear wall subsystems had a significant impact on the connection damage of CLT shear wall subsystems. The MaxISDR performed well in characterizing damage to glulam frame subsystems, while it could not reflect damage to CLT shear wall subsystems given that the Spearman’s rank correlation coefficient between the MaxISDR and the MaxCDI of CLT shear wall subsystems only reached −0.07. The MaxISWDI was capable of quantifying connection damage of CLT shear wall subsystems, with a Spearman’s rank correlation coefficient of 0.87.