Effect of different modelling approaches on the prediction of the seismic response of multi-storey CLT buildings

This work reports a summary of different type of analyses and modelling approaches, typically adopted by practitioners and researchers for the prediction of the seismic response of multi-storey CLT buildings. Specifically, two different modelling approaches are deeply investigated and compared; the first one is a component approach, which adopts springs (linear or non-linear) for connections, while the second one is based on a simplified phenomenological model where the behaviour of the system is reproduced by means of diagonal springs (linear or non-linear). The advantages and disadvantages of the two approaches are presented and critically discussed with reference to the types of the performed analysis (linear or non-linear). In order to verify the capability of the two modelling approaches to predict the seismic response of CLT structures performing linear analyses, a series of multi-storey buildings with increasing number of storeys and increasing values of design PGA are investigated. Obtained results are compared in terms of principal elastic periods, internal forces in the connection elements and drifts. Moreover, some correlations between results from the component and the phenomenological approach are given. Then, a first attempt of defining a numerical model suitable for non-linear analyses of a single CLT shear-wall, according to both the component and the phenomenological approaches is presented. Finally, the obtained results are discussed, highlighting the key issues in non-linear modelling of CLT structures.