Strong-Drive® Screw Installation for LVL, PSL and LSL

Simpson Strong-Tie® Strong-Drive screws (SDS) screws are an easy to install method for joining multiple SCL members to make a beam.

Installation:

No pre-drilling required.
See illustrations for SDS positioning on different assemblies.
SDS screws install best with a low speed 1/2" drill with a 3/8" hex head driver.
Do not over-drive the SDS screws.

Design:

SDS allowable load values are from ICC ESR-2236. The Designer shall apply adjustment factors per the NDS. Loads shown are C_D = 1.0. Increase as allowed per code to a maximum C_D = 1.60.
This document uses Douglas Fir-Larch values (G = 0.5), as per the LVL, PSL and LSL manufacturer's instructions.
The designer shall specify the location of all screws (stagger screws on opposite faces). Minimum recommended spacing - Wide Face: end distance 4", edge distance 1 1/2", spacing parallel to grain 4", spacing perpendicular to grain 2".
Uniform loads in the table below are based on the capacity of the fasteners to transfer loads between plies. The capacity of the LVL beam may be less and should be checked by a qualified Designer or with the manufacturer’s literature.
LSL applications that require 4 1/2" and 6" screws (Assembly B2, C and F) are limited to interior-dry use only.

Assemblies A-F show Laminated Veneer Lumber (LVL)
Also see Connector Selector Software.

roll over images below to see larger image


Simpson Strong-TieStrong-Drive Screw	Assembly A 2 - 1 3/4" SDS 1/4"x3 1/2"	Assembly B1 3 - 1 3/4" SDS 1/4"x3 1/2"	Assembly B2 3 - 1 3/4" SDS 1/4"x4 1/2"


Assembly C 4 - 1 3/4" SDS 1/4"x6"	Assembly D 1 - 1 3/4", 1 - 3 1/2" SDS 1/4"x3 1/2"	Assembly E 2 - 1 3/4", 1 - 3 1/2" SDS 1/4"x3 1/2"	Assembly F 2 - 3 1/2" SDS 1/4"x6"

Also see Connector Selector Software.

If 7" beams are not equally loaded on each side, the plf load from the lesser side should be at least 25% of the opposite side.
Quantity and spacing of screws in table are for each screw head side of the assembly as shown in the Assembly figures above.
The design professional shall ensure that adequate lateral bracing is provided to prevent displacement of the beam due to the torsion created by the structural members framing into the side of the beam assembly.
LSL applications involving Assemblies B2, C and F are limited to interior-dry use only.