Multi-Ply Wood Trusses - Girder Trusses

Install Strong-Drive^® screws a minimum of 1 inch into the last truss ply, with a maximum gap of 1/8" allowed between each truss ply.
Screw spacing shall not exceed 24" o.c.
Hanger load spacing on the multiple-ply truss shall not exceed 24" o.c.
The Truss Designer shall ensure that adequate lateral bracing is provided to prevent displacement of the truss and the truss bottom chord due to the torsion created by the structural members framing into the side of the multiple-ply girder truss.
Strong-Drive screws may be installed with the heads in either the loaded or unloaded ply (see Allowable Shear Loads table). For unloaded ply applications, hanger face nails shall be a minimum of 3" long.
Strong-Drive screws are permitted to be installed through metal truss plates as approved by the Truss Designer, provided the requirements of ANSI/TPI 1-2007 Section 8.9.2 are met (pre-drilling required through the plate using a maximum of 5/32" bit).
Use 1 row of SDS's in 2x4 members, 2 rows in 2x6 and 2x8 members, 3 rows in 2x10 members. Rows should be staggered.
Individual screw locations may be adjusted up to 1/2 of the required screw spacing to avoid conflicts with other hardware or to avoid lumber defects.

Also see Two-Ply 4X2 Floor Trusses and Alternate Installations.

roll over images below to see larger image


Simpson Strong-Drive^® screw U.S. Patents 6,109,850 / 5,897,280 / 5,044,853


SDS Installation in Loaded Ply		SDS Installation in Unloaded Ply

Quik Drive® Auto-Feed System For 2-Ply And 3-Ply Girders
Simpson Strong-Tie Quik Drive WSNTL wood screws are a safe, fast and reliable method for attaching multi-ply trusses. The QD WSNTL screws,like their SDS counterparts, virtually eliminate ply separation during handling.

roll over images below to see larger image


Simpson Strong-Tie Quik Drive WSNTL Series Screw


WSNTL Installation in 2-ply and 3-ply Assemblies

Where noted allowable loads are based on ESR-2236.
The Truss Designer shall apply all adjustment factors required per the NDS.
Loads are based on 1 1/2" thick wood side members and apply to 3 and 4 ply 2x wood truss applications. (Side and main members of same wood species.) Contact Simpson Strong-Tie for other applications.
LSL applications are limited to interior-dry use only.