Advancing Nonlinear Design of Buildings under Extreme Wind Loads

Performance-based wind engineering has gained considerable interest among researchers and practicing engineers due to its potential benefits in improving structural performance, safety, and economy of buildings and other structures. One of the main requirements for successful implementation of performance-based wind design is to have a thorough understanding of the nonlinear response of the building up to collapse, even when collapse is unlikely in wind events. Currently, there is very little knowledge on the prediction of the nonlinear wind-induced response of the building structures. The main objective of this dissertation is to improve our understanding of the nonlinear wind-induced response of the buildings under extreme wind loads to advance performance-based wind design methods. To achieve this goal, this doctoral study has investigated the importance and necessity of performance-based wind design of the buildings in terms of safety and economy of the design by conducting a detailed performance-based assessment of a 20-story steel-moment resting frame as a case study through both deterministic and probabilistic approaches. The nonlinear response of the frame up to the collapse point when subjected to strong wind storms was also investigated using the two deterministic and probabilistic approaches as well. The simulation results were used to investigate the importance of adding uncertainties in the prediction of wind-induced response of the buildings by comparing the predicted frame response obtained from the deterministic and probabilistic simulations. Additionally, the effect of nonlinear building behavior on the variation of aerodynamic feedback measured from low-rise, mid-rise, and high-rise buildings was investigated. The effect of nonlinear building response on initiating or intensifying wind-induced instabilities, such as vortex-induced vibration, is also studied. The overall outcome of the study highlights the highly conservative design of the elements of the main wind force resisting systems. Meanwhile, the serviceability performance objectives for the considered buildings did not meet the acceptance criteria when both deterministic and probabilistic approaches are employed. The importance of incorporating uncertainties into the wind-induced response of the building especially as the level of nonlinearity increases is another key finding of this study. Finally, it was shown that the nonlinear behavior of the buildings does not cause any additional adverse FSI effects, and in fact, could even help with improving structural stability in cases of low inherent structural damping levels due to the hysteretic energy dissipation