Implication of city growth on wind-induced loads for cladding and structural design
Abstract
As cities grow, the urban topology changes in density resulting in continuous variations in wind flow. The interaction of flow with this changing surrounding environment drives the aerodynamics to become more complex and varying, subjecting the building to significant changes in wind-induced-loads both on structural and non-structural elements. In this study, a series of boundary layer wind tunnel tests are conducted to investigate the impact of city growth on cladding and structural loading by using a typical tall building adopted from the Commonwealth Advisory Aeronautical Council (CAARC) building model. The city growth is represented by five different generic surrounding configurations, varying in height ratios compared to the study building of height (H). The configuration includes isolated case (0000SH), surrounded with 0.25H height (0025SH), 0.5H height (0050SH), 0.75H height (0075SH) and H height (0100SH) of surrounding buildings, respectively. Based on the study analysis, the city growth has different impact on structural and non-structural elements from wind hazard perspectives. The overall recorded mean wind pressures are reduced while fluctuations within these pressures are increasing as the urban environment becomes denser creating wake induced turbulence. Due to Bernoulli and Venturi effect, local pressure increases are observed for certain cases. The results show 30% increase in the negative peak pressures Čp for case 0050SH at a value of -7 compared to the isolated case scenario 0000SH at AoA=90° which subject the building to higher risk of cladding failure. From the main wind force resisting system, the mean and fluctuating base moments reduced by 20% for case 0050SH and 50% for case 0075SH which consequently decreased the peak base moments and top peak acceleration on the structural system.