Cyclic behavior of bracket connections for cross-laminated timber (CLT): Assessment and comparison of experimental and numerical models studies

This paper reports the comprehensive test and numerical models assessments for uniaxial cyclic behaviors of standard bracket connections for cross-laminated timber (CLT). Five analysis methods are compared for the determination of yield points of CLT connections. The applicability of the methods to various types of CLT bracket connections is discussed in order to identify the most universal approach. Key mechanical properties of bracket connections such as strength, stiffness, yield point, failure point and ductility are shown and compared. Pinching4 hysteretic model is used and calibrated to match the experimental hysteretic curves. The damage index error based on energy-based accumulation principle is applied to assess the precision of the model on hysteretic details. It is found that the Yasumura&Kawai approach provids a suitable estimation of the yield point based on bilinear approach, avoiding underestimation like the CSIRO and Karacabeyli&Ceccotti methods and improving results from the methods of EN 12512 and ASTM E2126. The damage indicator can precisely indicate the quality of correlation between experimental results and model predictions. The Pinching4 model is proved the ability in modeling the cyclic experimental uniaxial behavior of the CLT bracket connections. It can capture most details of hysteretic load-displacement curves and offer closer predictions to the test results in the advanced stage of loading to damage. But it has limited abilities for modeling high unloading stiffness at the initial stage for CLT connections.