Nonstructural Design Requirements for Functional Recovery Performance

Work is underway in the United States to develop the first generation of prescriptive seismic design provisions for functional recovery. The Building Seismic Safety Council (BSSC) has proposed targeting a 25% probability of exceeding 0 days for functional recovery category (FRC) A, 3 days for FRC B, 2 months for FRC C, and 6 months for FRC D at the functional recovery earthquake. This article explores the nonstructural component design requirements necessary to meet these targets for FRC B to D, when lateral force‐resisting systems are designed to achieve a low probability of safety‐critical structural damage. First, we consider a portfolio of buildings that includes reinforced concrete shear walls, steel buckling restrained braced frames, and steel and reinforced concrete moment frames, with heights ranging from three to 24 stories. We simulate building responses for a typical office occupancy at a representative Seismic Design Category D max ,FRE site to ensure results can be generalized across high seismicity regions. We then estimate damage and functional recovery performance using the FEMA P‐58 and ATC‐138 methodologies. The functional recovery performance is assessed for increasing component design forces by varying the seismic component importance factor for functional recovery, I pfr , from 1.0 to 3.0, which is applied to both drift‐ and acceleration‐sensitive components. We also evaluate the impact of seismic qualification of equipment. While variability across systems is observed, the results show that (1) seismic qualification is necessary and (2) an I pfr of 1.75 for FRC B, an I pfr of 1.5 for FRC C, and an I pfr of 1.25 for FRC D are required to meet the corresponding performance objectives across the systems and heights considered. This article ultimately aims to inform the nonstructural design requirements in the 2026 National Earthquake Hazards Reduction Program recommended provisions for functional recovery.