Reliability-Based Assessment of LTF and CLT Shear Walls under In-Plane Seismic Loading Using a Modified Bouc-Wen Hysteresis Model

This paper reports on the reliability-based assessment of light timber frame (LTF) and cross-laminated timber (CLT) shear walls. The outcomes of cyclic tests on 17 timber shear wall specimens calibrate the parameters of a modified Bouc-Wen model [extended energy-dependent generalized Bouc-Wen (EEGBW)] obtained from the extension of the generalized Bouc-Wen (GBW) model. The EEGBW model, which is an alternative to the Bouc-Wen-Baber-Noori (BWBN) one, accurately, simulates the essential features of timber connections and structural systems. The EEGBW model, representative of the global response of the shear wall, expresses the resisting term of a single-degree-of-freedom dynamic system, which describes the seismic response of a lumped mass supported by the shear walls. The results of truncated incremental dynamic analysis in terms of maximum displacement lead to the failure probabilities associated with increasing intensity measures. The resulting failure probabilities, fitted by a lognormal probability function, deliver the so-called fragility functions of the 17 structural archetypes by assuming three different mass values. The failure probabilities return the estimation of the reliability indexes, which quantitatively assess the seismic reliability of the considered structures. Additionally, the authors discuss the role of the top mass and its effects upon the shear walls' seismic performance by comparing the LTF and CLT structural systems.