Effects of reentrant corners on wind loads for non-rectangular-plan buildings

Although irregular plan shapes are common in modern construction, wind load provisions for low-rise buildings continue to treat simple rectangular buildings as the default case and offer little explicit guidance for irregular geometries. ASCE 7–22 suggests that standard rectangular-based wind load provisions conservatively envelope most irregular structures, though this assumption remains largely unvalidated for low-rise structures. This study presents wind tunnel results for a range of irregular building models tested under multiple wind directions, terrains, and geometries. Each configuration is compared directly to its equivalent rectangular footprint. Contrary to the prevailing assumptions, the results show that irregular shapes with reentrant corners can produce higher base shear and uplift loads than their rectangular counterparts. The increase in base shear is primarily driven by how reentrant corners shorten the effective distance between windward and leeward faces, leading to higher suction pressures on the leeward wall. Increased uplift is attributed to three main aerodynamic mechanisms: area effects, where similar pressures act over relatively larger portions of the roof on irregular shapes; windward wall effects, where recessed roof edges experience suction more akin to fully exposed windward edges; and corner effects, where the geometry produces multiple zones of high suction without increasing the peak value but resulting in greater overall uplift. These findings highlight the need for improved guidance on wind loading for irregular low-rise buildings with reentrant corners.