Cross-Laminated-Timber (CLT) is increasingly gaining popularity in residential and non-residential applications in North America. To use CLT as lateral load resisting system, individual panels need to be connected. In order to provide in-plane shear connections, CLT panels may be joined with a variety of options including the use of self-tapping-screws (STS) in surface splines and half-lap joints. Alternatively, STS can be installed at an angle to the plane allowing for simple butt joints and avoiding any machining. This study investigated the performance of CLT panel assemblies connected with STS under vertical shear loading. The three aforementioned options were applied to join 3ply and 5-ply CLT panels. A total of 60 mid-scale quasi-static shear tests were performed to determine and compare the connection performance in terms of strength, stiffness, and ductility. It was shown that – depending on the screw layout – either very stiff or very ductile joint performance can be achieved.
April 3-5, 2014, Boston, Massachusetts, United States
The goal of this research was to develop a structural system for tall buildings using mass-timber as the main structural material that reduces the carbon dioxide emissions associated with the structure. The structural system research was applied to a prototypical building based on an existing concrete benchmark for comparison.
This paper discusses key design issues associated with tall mass-timber buildings along with potential solutions. It is believed that the system proposed in the research and discussed in the paper could mitigate many of these design issues. The main structural mass-timber elements are connected by steel reinforcing through cast-in-place concrete at the connection joints. This system plays to the strengths of both materials and allows the designer to apply sound tall building engineering fundamentals. The result is believed to be an efficient structure that could compete with reinforced concrete and structural steel while reducing the associated carbon emissions by 60 to 75%.