Effects of Non-Structural Walls on Vertical Floor Acceleration Demands: A Case Study

Non-structural components (NSCs) are highly susceptible to seismic damage, often driving major economic losses. This vulnerability is exacerbated in near-fault zones, where vertical ground motions can exceed horizontal components, challenging conventional NSC design approaches and amplifying safety risks. This study investigates how different non-structural wall configurations affect vertical floor acceleration demands and quantifies the corresponding demands on suspended ceilings. Linear time-history analyses were conducted on various structural models: (bare frame, full frame, two variants of masonry-wall-only frames, and one curtain-wall-only frame) using 65 strong vertical ground motions ('0.25 g). Computed PFAᵥ/PGAᵥ ratios show that masonry-wall only frames with walls on lower stories significantly amplify vertical accelerations on upper floors, with mid-story peaks exceeding 3.6 × PGA _v. In contrast, curtain-wall-only frame exhibits more uniform responses. Roof-level amplifications remain moderate (3.0–3.5 × PGA _v) across all configurations. Notably, floor level responses exhibited up to 100% variability at different nodes on the same story highlighting the impact of irregular wall distributions. Suspended ceilings experienced, on average, 20% (84thpercentile) higher vertical accelerations than their supporting floor. Based on these findings, two recommendations are proposed: (1) A baseline vertical amplification factor of 3.00× PGA _v adjusted for wall configurations and floor location; (2) A 1.20 amplification ratio for estimating suspended ceiling accelerations relative to supporting floor.