Where do trusses usually fail first?

• A. The apex joints
• B. Moments in the member spans
• C. The connections (gang nail plates)
• D. At the foot of the truss

Answer: (C)

Joints do the heavy load transfer in a truss. The members are meant to act mainly as axial elements, so the way they’re tied together is the limiting factor. The gang nail plates that connect the top and bottom chords to the web members are the critical links; if those plates loosen, nails withdraw, or the wood around the plates deteriorates, the joint can’t transfer forces properly and the truss fails there first. Other potential failure sites—like bending moments within spans or the foot bearing—are less likely to fail first in a well-designed wood truss, because the members are intended to carry axial loads and the connection is the loads’ bottleneck.