An upgrade of existing practice-oriented FE design models for the seismic analysis of CLT buildings

Practice-oriented finite element (FE) modelling strategies represent a fundamental tool for the seismic analysis and design of Cross Laminated Timber (CLT) structures. Although substantial research has been undertaken concerning the seismic behaviour of CLT buildings, practice-oriented FE modelling strategies are still at an early stage. This paper presents an upgrade of an existing practice-oriented FE design model for the seismic design of CLT structures. The upgrade is supported through the same modelling strategy presented by Christovasilis et al. (2020) adding some features of analytical equations models presented by Casagrande et al. (2016). 2D elements are used both for the modelling of CLT panels and for mechanical connections, which are represented by a horizontal strip with a height smaller than 7% of the height of the panel. Analytical equations for determining the elastic modulus of elasticity and the shear modulus of the horizontal strip are reported accounting for both rocking and sliding behaviour for single- and multi-panel CLT shearwalls, including the effect of the vertical loads by using a secant stiffness. The validation of the proposal is carried out in terms of the shearwall lateral stiffness through the results of experimental tests on full-scale shearwalls published by other authors and through a validation/comparison between a detailed non-linear model and the Christovasilis et al. (2020) strategy on two multi-storey seismic-resistant lateral systems configurations with different amount of vertical loads. Finally, a proposal for the initial layout of connections to reduce the iterative seismic design and analysis process for CLT buildings is presented through a case study.