Experiment And Finite Element Analysis On Mortise-Tenon Connected Cross-Laminated Timber Wall Joint Under Out-of-Plane Loading

Cross-laminated timber(CLT)is the new generation of engineering wood products,commonly used as structural components in massive timber structures to build mid-to high-rise buildings.CLT structures are mostly designed as shear wall systems,where connection acts as the energy dissipative zone to absorb seismic energy and provides ductility.These CLT joints are normally consist of metal connecters,which can provide the structure with certain amount of ductility but restrict the performance of the whole structure to some extent.Whereas in traditional wooden structures,mortise-tenon joint is a typical form of connection which apply only wood to join components.A well-designed mortise-tenon joint not only allows load transfer effectively between structural components,but also inherently has the advantage of absorbing energy.Therefore,in this paper we proposed a concept of applying mortise-tenon joint to CLT wall system.Monotonic and cyclic loading experiments were conducted on two types of mortise-tenon joints we came up with,namely the double-dovetail joint and the dovetail joint.The mechanical performance of both type of joints subjected to out-of-plane loads were given and further discussion on the influence of the tenon end width on these performances were presented.In terms of the joint's mechanical properties,double-dovetail joint showed a decrease trend when increase the tenon end width.When the width further increased,the mechanical properties increased again.For the dovetail joint,the joint's performance increased with the increase of the tenon end width.From the seismic aspect,the performance of the double-dovetail joint was influenced by the rotation and the end width of the connector.In case of dovetail joint,the tenon end width influenced different mechanical properties in different ways.Furthermore,suggestion on the design of the tenon end width for each type of the joint were given accordingly.For the double-dovetail joint,the ratio between the tenon end width and the wall panel thickness should not exceed 2/3.For the dovetail joint,when the ratio was set as 4/5,the joint can achieve a better performance.The finite element model of the dovetail connected CLT wall joint built in ABAQUS was then presented.This model was validated by comparing the results from the finite element analysis and the experiment.Based on the FE model,the load transfer path and weak points in the joint were figured out.According to the stress and displacement distribution,suggestion on the optimization of the joint for the future design were then given.