Wind-Induced Torsional Loads on Irregular-Shaped Mid-Rise Buildings

Wind-induced torsional loads on mid-rise buildings represent a critical aspect of structural design, particularly as urban landscapes increasingly feature complex building geometries. The inherent complexities of these shapes result in highly variable wind pressure distributions, which can lead to significant variability of torsional effects that existing wind design guidelines may inadequately address. This research aims to reduce this knowledge gap through rigorous experimental studies focused on evaluating the aerodynamic forces exerted on irregular-shaped mid-rise residential buildings.In recent decades, considerable advancements have been made in understanding wind-induced forces acting on structures. However, research specifically targeting wind-induced torsional loads remains limited. With the ongoing trend toward constructing more intricate building designs, the potential for unbalanced wind loads—and consequently torsional moments—has increased. This imposes a need for critical reassessment of current wind load provisions to ensure their effectiveness in evaluating torsional impacts on low- and mid-rise buildings, ultimately leading to more resilient and economically viable designs.Historically, much of the research on wind loading provisions concerning torsion has centered on very tall and flexible buildings, where the resonant response significantly influences performance. In contrast, the dynamic behavior of most low- and mid-rise buildings is predominantly governed by quasi-steady gust loading, with minimal resonant effects. This discrepancy highlights the urgent need for developing guidelines that accurately address torsional loads for a broader range of building types with the aforementioned criteria.Furthermore, wind loading codes exhibit variability in their approaches to evaluating torsion, often leading to ambiguous or inadequate guidance. These inconsistencies reflect a significant knowledge gap, as wind-induced torsional loads have not been thoroughly integrated into standard design guidelines. While various studies have extensively examined local wind pressures and total effective wind forces on mid-rise structures, the analysis of torsional loads remains underexplored.The dynamics of a fluid (e.g., wind) around buildings are highly sensitive to the structures’ shapes and surrounding environments. Wind turbulence, combined with interactions between the wind and the building results in variable loads that fluctuate over time and across different spatial dimensions.To address these challenges, this study assesses wind-induced torsional loads on irregularly shaped mid-rise buildings through wind-tunnel testing conducted at the Wall of Wind (WOW) Experimental Facility, using flat-roof scaled models (1:50) of 1- to 4-story configurations, instrumented with pressure sensors to collect wind pressure data. Preliminary findings indicate a significant deviation in torsional loads between rectangular and irregularly shaped buildings; for example, the torsional coefficient for a T-shaped building was found to exceed double that of a rectangular baseline model.As the research progresses, updated results are anticipated to further elucidate the effects of complex building layouts on wind-induced torsional loads. Ultimately, this work aims to provide valuable insights to enhance wind design guidelines and refine vulnerability or fragility functions pertinent to various building shapes and components. By fostering a deeper understanding of torsional effects, the study will contribute to the advancement of more resilient and effective design practices for mid-rise buildings in wind-prone areas.