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Component Manufacturing dverti$ dverti $ er
By Paul McEntee
Don’t Forget! You Saw it in the
May 2023 #15286 Page #96
Adverti$$er
Mass Timber Diaphragm Options with Four Different Connection Types — How Our LDSS48 Light Diaphragm Spline Strap Evolved
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loors and roofs on mass timber buildings are constructed from large panels of engineered wood, such as cross-laminated timber (CLT) or mass plywood. Designers join these prefabricated panels together on site to create a structural horizontal diaphragm to transfer wind and seismic loads to the vertical elements of the lateral force resisting system. Shear forces between panels must be transferred through these panel-topanel connections. Conventional wood structural panel sheathed diaphragms have shear capacities and fastener spacing tabulated in Special Design Provisions for Wind and Seismic (AWC SDPWS). Mass timber diaphragms, on the other hand, require some more design work by the designer.
Simpson Strong-Tie has provided designers with several diaphragm options to satisfy load requirements using four different connection types. Plywood splines are recessed into edge milling of the CLT panels and fastened with screws or nails. Steel splines can generally be installed on the surface of the CLT panels without edge milling, and are fastened with screws or nails. Butt joints are connected with fully threaded screws driven at an angle on alternating sides of the joint. Half-lap joints require edge milling so panels can overlap at the joint and the connection is made with screws driven perpendicular to the surface.
Plywood Spline
MDSS Steel Spline
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