Numerical Seismic Analyses of Multi-Storey CLT Structures with High-Performance Connections

A high-performance connection system for the elastic design of medium/high-rise CLT buildings, named H-LAM, is studied in this paper. The connection, which can replace “hold downs” and “angle brackets" with a single solution, is made of welded metal plates which are connected to the timber panels with fully threaded inclined screws. Because the screws mainly work in extraction, the connection reaches high values of stiffness and resistance when subjected to shear or tension forces. In the case of seismic events that exceed the design intensity, the progressive extraction of the screws involves the activation of a pseudo-ductile failure mechanism. Additionally, the H-LAM system permits the transfer of vertical actions from the upper wall panel to the lower one with no compression orthogonal to the grain of the floor panel. The connection has been studied via numerical modelling and experimental tests. In this study, the H-LAM was applied to three casestudy structures which present the same plan shape but a different number of stories (i.e., 4, 6 and 8). Two seismic scenarios were assessed for each structure via nonlinear static analyses. The analysis results permitted the validation of the suitability of the proposed connection to be used in the elastic design of medium/high-rise CLT structures.