Reliability-based overstrength factors of cross-laminated timber shear walls for seismic design.

• Reliability methods drive the assessment of overstrength ratios in Cross Laminated Timber structures. • There is a satisfactory agreement between the experimental lateral response of Cross-Laminated Timber panels and the simulations based on the Extended Energy-dependent Generalized Bouc-Wen model. • Given a certain failure probability, the overstrength factor is estimated as the ratio between the failure Peak Ground Acceleration of the ductile and brittle system. • The obtained overstrength ratios range between 1.5 and 2.5. • The obtained overstrength ratios are in accordance with those obtained by other scholars following non-probabilistic approaches. The ductile collapse mechanisms of structures should be less resistant than the brittle mechanisms to ensure a ductile seismic response: in this way, the ductile mechanisms activate before the brittle ones. This sort of chronological law of collapse is obtained in the design phase by providing a proper "overstrength" to the brittle mechanisms. The realization of overstrength plays a crucial role in the design, and several studies endeavoured to estimate the best overstrength factors, defined as the ratio between the characteristic load-carrying capacity of the non-ductile element and the characteristic load-carrying capacity of the ductile element. In this paper, the conventional definition of overstrength is discussed and compared to a probabilistic definition based on reliability methods. The probabilistic definition of overstrength drives the assessment of the overstrength factors of Cross-Laminated Timber buildings using a sort of indirect approach. The Extended-Energy dependent generalized Bouc-Wen model is used to estimate the nonlinear seismic response of a set of Cross-Laminated Timber shear walls with different ductility. The results are compared with the existing formulations, attempting to draw correlations possibly useful in the design phase. [ABSTRACT FROM AUTHOR]