Pathology of Seismic Deficiencies in Non-Structural Walls and Facades: Lessons from As-Built Practice

Non-structural elements (NSEs), particularly walls and façades, are among the most vulnerable components of buildings during earthquakes. Although their failure rarely leads to structural collapse, it causes significant economic loss, operational disruption, and life-safety hazards from falling debris. This study presents a pathological assessment of NSE performance based on extensive reconnaissance of buildings damaged in recent Iranian earthquakes. Damage patterns in reinforced concrete, steel, and masonry structures were systematically documented, classified, and compared with national code requirements. The findings reveal recurring and predictable failures: in-plane mechanisms such as diagonal shear cracking, corner crushing, and sliding shear were common, while catastrophic out-of-plane collapses occurred frequently due to inadequate anchorage. Heavy stone façades installed with wet-mortar methods showed widespread detachment, creating severe falling hazards. These deficiencies stem from poor workmanship, weak supervision, and the general neglect of the building envelope as a seismic performance system. The study concludes that NSE vulnerability reflects not a lack of regulation, but a conceptual failure. Despite comprehensive codes, non-compliance and flawed design approaches persist. Closing this gap requires a professional shift that integrates seismic design principles into practice, treating the building envelope as a critical life-safety component rather than a decorative surface.