Brace frame building usually collapse in a(n) ______ configuration.

Brace frame building usually collapse in a(n) ______ configuration.

• A. Inward/Outward
• B. Vertical
• C. Outward/Inward
• D. Diagonal

Answer: (A)

When a brace frame is pushed hard by lateral forces, it tends to fail through an inward/outward movement pattern. Picture the diagonals forming an X: as some braces reach their yield point in tension and the others buckle in compression, the frame twists so that one side of the structure moves inward while the opposite side moves outward. This opposite-direction sway causes a loss of lateral stiffness and creates a collapsible mechanism, which is why this inward/outward configuration is the characteristic failure mode. This contrasts with a purely vertical collapse, which would imply bending or buckling in the vertical members rather than a lateral, opposite-direction sway, and with a simple diagonal issue, which doesn’t capture the alternating inward and outward movement seen in brace-frame failures.

When a brace frame is pushed hard by lateral forces, it tends to fail through an inward/outward movement pattern. Picture the diagonals forming an X: as some braces reach their yield point in tension and the others buckle in compression, the frame twists so that one side of the structure moves inward while the opposite side moves outward. This opposite-direction sway causes a loss of lateral stiffness and creates a collapsible mechanism, which is why this inward/outward configuration is the characteristic failure mode.

This contrasts with a purely vertical collapse, which would imply bending or buckling in the vertical members rather than a lateral, opposite-direction sway, and with a simple diagonal issue, which doesn’t capture the alternating inward and outward movement seen in brace-frame failures.