Assessment and comparison of experimental and numerical model studies of cross-laminated timber mechanical connections under cyclic loading

Earthquake engineering is a major consideration for structures along the west coast of North America. The current building code of Canada is based on design criteria, which are defined by stresses and member forces calculated from prescribed levels of applied lateral shear force. Traditional wood-frame buildings are known to perform well in earthquakes. However, with the development of new engineered wood products, such as CLT (cross-laminated timber) and more consideration to build higher than the existing six stories limit in wood-frame structures, highlights the need to use innovative hybrid techniques for buildings. Hybrid buildings with steel frame structures incorporated with CLT infill walls offer one possible solution to residential and commercial multi-level buildings to overcome the height limitation. In order to make such a structure applicable for an earthquake prone area, it is important to understand the structural performance of the connection between steel and CLT elements. In this research, six connection combinations have been tested and modeled in a finite element program. The load-displacement test results are assessed with two evaluation methods. The first method follows the American Society of Testing Method, where ductility ratio, elastic shear stiffness, and the EEEP-curve (equivalent energy elastic-plastic curve) are generated and assessed. The second method follows an energy-based accumulation principle, where the test results are used to calculate a damage index at each time step. Both methods are used to compare test and model results and assess the accuracy of the model as well as addressing the capability of each assessment method. Depending on the purpose of the model one or the other assessment method might be suitable. For an analysis of the overall ductility or elastic shear stiffness, applying the method provided by ASTM will give relatively accurate results to assess a hysteretic load-displacement model such as the SAWS model in this research. The assessment with a damage accumulation method is a great tool to capture more details of the hysteretic load-displacement curve. Energy dissipation is valuable indicator besides ductility and elastic shear stiffness to evaluate the model. (C) 2014 Elsevier Ltd. All rights reserved.