How does seismic design influence plastic hinge location and detailing?

• A. Hinges form in mid-span.
• B. Hinges form in brittle zones near columns.
• C. Hinges are avoided entirely.
• D. Hinges form in ductile locations near the ends of columns and beams.

Answer: (D)

Seismic design uses inelastic deformations to dissipate energy in a controlled way, so the structure yields at specific, well-protected locations. Plastic hinges are placed in ductile regions near the ends of beams and columns because those areas can develop large rotations with proper confinement and detailing without sudden, brittle failure. This end-region location lets the frame yield in a predictable sequence, redistributing moments as lateral drift increases, which helps prevent collapse. Hinges away from these ductile ends or in brittle zones would lead to uncontrolled failure, and hinges are not avoided—they are deliberately engineered to form where they can be most safely sustained.