Is it safe to load screws laterally in the end grain?

Standard design procedures in CSA O86 and NDS 2018 account for strength reductions associated with end grain installation, but member strength must also be considered.
The European Yield Model (“Yield Limit Equations” in the NDS), only considers the fastener and the immediately surrounding wood in static equilibrium. Designers must also consider possible wood member failures such as premature splitting. The potential for splitting when fasteners are loaded laterally in the end grain depends a lot on the type of loading, support conditions, and member length. For instance, example image 1, for a short span member loaded with the fastener located a sufficient distance away from the loaded edge (see When do I need to reinforce pre-engineered connectors?), the design assumptions of the European Yield model may govern. However, a long-span member subject to bending with the fastener located close to the loaded edge (example image 2), significant tensile stresses can develop perpendicular to the grain (indicated with the solid red triangle) causing premature splitting along the red dotted line.

The type of failure shown in image 2 is rarely a concern with short-span sill plates with small, slender fasteners, for example. However, since mass timber is often associated with long-span members, designers should be mindful of this failure mode, for example, when designing with end-face beam hangers and CLT panels loaded out-of-plane. In some applications, designers may consider the possibility of reinforcing members with fully threaded screws to prevent premature splitting.
Normal blog1

Relevant Technical Resources

Gallery wp high performance beam post connections High Performance Beam to Post Connections

Products Covered in this Article

Gallery assy eco explosion resized ASSY Eco Countersunk Head
Gallery eco a2 ASSY Eco Stainless Steel
Gallery assy fwh explosion resized ASSY FWH Flat Washer Head
Gallery assy kombi explosion resized ASSY Kombi
Gallery kombi a2 ASSY Kombi Stainless Steel
Gallery sk a2 ASSY SK Stainless Steel
Gallery assy sk explosion resized ASSY SK Washer Head
Gallery assy vg csk explosion resized ASSY VG CSK Counter Sunk Head
Gallery assy vg cyl explosion resized ASSY VG CYL Cylinder Head
Gallery assy vg rh explosion ASSY VG RH Reverse Head
Gallery gigant system GIGANT
Gallery megant system MEGANT
Gallery ricon s vs cover picture explosion RICON S VS
Gallery walco v system WALCO

Still Have Questions? Send Us an Email and an Engineer Will Assist You

Or Call Us at