Fragility functions and behavior factors estimation of multi-story cross-laminated timber structures characterized by an energy-dependent hysteretic model

The authors assessed the fragility functions and behavior factors of cross-laminated timber (CLT) structures. The structures derive from the assembly of single CLT wall panels characterized by different configurations. The extended energy-dependent generalized Bouc-Wen (EEGBW) hysteresis model describes their inelastic behavior: the experimental data obtained by Gavric et al. are used to calibrate the hysteretic models of the considered cases. The truncated incremental dynamic analysis of the building models under a set of earthquake records yields the fragility functions and behavior factors. The copious results allow a comparative study between multiple structural configurations characterized by different constructive features. The behavior factors match those already proposed by the scientific literature. An analytical relationship was estimated relating the behavior factors and a suite of parameters (e.g. joint density, slenderness ratio of the CLT panel, and number of stories) representative of the tested cases. The fragility functions evidence the notable role of the number of stories over the failure probability, rather than the particular wall configuration.