High-capacity hold-down for mass-timber buildings

Engineered mass-timber products such as cross-laminated timber enable the use of timber as structural material in tall buildings. One of the advantages of using timber is the reduction in weight and the resulting reduction in foundation costs. A lower structural mass, however, will also lead to less inherent resistance to overturning forces caused by lateral loads such as wind. This paper summarizes the experimental studies on a novel high-capacity hold-down solution for tall timber structures. The connection assembly consists of a modified Holz-Stahl-Komposit (HSK)™ application: perforated steel plates that are adhesively bonded into the timber panel with duct tape being used to cover some rows of the holes in the perforated plate. This arrangement allows the perforated steel plate to yield inside the timber which prevents lateral buckling of the hold-down. A total of 54 tests at material, component and full-scale hold-down level were conducted using quasi-static monotonic and reversed cyclic loading. The results demonstrated that the modified HSK hold-down assembly provides high initial stiffness as well as the required capacity and ductility for seismic applications in tall mass-timber buildings.