Experimental and numerical analysis of residual load-carrying capacity of cross-laminated timber walls after fire

Cross-laminated timber (CLT) panels are widely used as structural members applied in a range of modern timber buildings. Changes in the load-carrying capacity of CLT walls after exposure to fire need to be discussed and summarized, but few studies have considered this due to a lack of available measurements and the prohibitive cost of performing the relevant experiments. To investigate the residual load-carrying capacity of CLT walls after fire, the multiple tests including axial compression tests under the ambient condition, standard fire tests and residual load-carrying capacity tests after fire were performed, and a numerical approach was developed in this study. The appropriate constitutive relationship and mechanical properties of timber affected by temperature were adopted, and the corresponding user-defined material subroutine was coded in ABAQUS and verified by typical examples. It was shown that the numerical models could reproduce adequately the failure process and mechanical behavior of the CLT specimens tested. The validated numerical method was used to carry out a parametric prediction that revealed the influence of the number of layers and the combustion time on the residual load-carrying capacity after fire. Moreover, the presented results could serve as a reference for the structural fire safety design of CLT structures.