1. Foundations
2. Bearings
3. Pier columns
4. Superstructure girders

Explanation

Explanation:

Capacity design intentionally concentrates inelastic demand in ductile, accessible components — typically pier columns — while protecting foundations and superstructure from brittle failure. Pier columns are detailed to form controlled plastic hinges above ground, where damage can be inspected and repaired after a seismic event. Keeping inelastic behaviour out of foundations is critical because foundation damage is difficult, expensive, and often impractical to repair. The objective is controlled ductile energy dissipation in accessible regions, not uncontrolled structural failure.

Learning Resources:

• CSA S6:19, Clause 4 – Seismic Design
• Priestley, Calvi & Kowalsky, Displacement-Based Seismic Design of Structures