Nonlinear analytical modeling of mass-timber buildings with post-tensioned rocking walls

The dynamic response of post-tensioned rocking walls in a mass timber building can be reduced to a single-degree-of-freedom (SDOF) model. In this model, the rocking wall panel is simplified as a rigid block, while the base rotation represents the degree of freedom of the entire structure. The paper presents an analytical approach to develop and calibrate this nonlinear model using shake table tests of a full-scale two-story building with CLT rocking walls. The experimental data are used to estimate the parameters of the governing equation using least-squares optimization. The correlation between the obtained parameters and the cumulative dissipated energy led to a nonlinear model with degradation behavior captured. After that, the calibrated model was used to assess the fragility functions of the structure under repetitive seismic events.