In wood truss design, which component is the weakest point?

In wood truss design, which component is the weakest point?

• A. Gusset plate
• B. Fire plate
• C. Bar joist
• D. I beam

Answer: (A)

The joints between the members determine the truss’s strength, and the weakest link is the gusset plate. This plate ties all the chords and webs together and carries the forces transferred through the fasteners (nails, screws, bolts). Those fasteners must resist shear and nail withdrawal, and the wood surrounding them must hold up under load. The gusset plate is thin and simply serves to hold the fasteners in place, so under load the joint is prone to slipping, tearing of the plate, or wood around the fasteners crushing or splitting. That makes the connection the most vulnerable part of the wood truss. Bar joists and I beams are steel structural members not part of typical wood-truss joints, and a fire plate isn’t a primary load-carrying member in this context, so they’re not the weakest point in a wood truss.

The joints between the members determine the truss’s strength, and the weakest link is the gusset plate. This plate ties all the chords and webs together and carries the forces transferred through the fasteners (nails, screws, bolts). Those fasteners must resist shear and nail withdrawal, and the wood surrounding them must hold up under load. The gusset plate is thin and simply serves to hold the fasteners in place, so under load the joint is prone to slipping, tearing of the plate, or wood around the fasteners crushing or splitting. That makes the connection the most vulnerable part of the wood truss. Bar joists and I beams are steel structural members not part of typical wood-truss joints, and a fire plate isn’t a primary load-carrying member in this context, so they’re not the weakest point in a wood truss.