Advanced Characterization of Inelastic Performance of Tall Buildings to Wind for Performance-Based Design

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This research project will develop efficient analysis frameworks for assessing the inelastic response of tall buildings under wind loads, which can be used to support performance-based wind design (PBWD). Current building design for wind loads does not explicitly permit structures to behave beyond the linear elastic limit, even under ultimate wind loads. This linear design approach may limit the use of more innovative tall building systems with improved performance, safety, and economy. There is very little information concerning the nonlinear inelastic performance of tall buildings to wind in terms of the actual capacity and reliability of buildings against extreme wind loads. This project will address the critical research needs and close the knowledge gap for achieving PBWD of tall buildings with consideration of inelastic behavior. The project outcomes will be used to enrich instruction and training of graduate students. This award will contribute to the National Science Foundation (NSF) role in the National Windstorm Impact Reduction Program (NWIRP). Project data will be archived and made publicly available in the NSF-supported Natural Hazards Engineering Research Infrastructure (NHERI) Data Depot (https://www.DesignSafe-ci.org). Computational tools developed under this project will be integrated with software framework of the NSF-supported NHERI Computational Modeling and Simulation Center. This research project has three specific objectives. First, the project will characterize the inelastic performance of tall buildings using high-fidelity, three-dimensional, nonlinear finite element building models with different heights and building structural systems under realistic three-dimensional dynamic wind loads. The response analysis will shed new insights on the unique characteristics of inelastic building response; biaxial and triaxial response interactions; influence of P-Delta, strength deterioration, and stiffness degradation; and influence of eccentricities in mass and rigidity. Second, the project will develop reduced-order nonlinear building models and analysis frameworks for assessing probabilistic inelastic response. Modal push-over analysis under uniaxial, biaxial, and triaxial loads will be implemented to generate hysteretic generalized force models and to develop reduced-order nonlinear building models with computational efficiency. The accuracy of reduced-order building models will be validated through comprehensive response history analysis and comparison with the predictions from the high-fidelity nonlinear finite element models. Statistical linearization approaches will be developed to further facilitate the predictions of inelastic response statistics. Third, the project will establish frameworks for assessing the reliability of buildings with inelastic performance. Various uncertainties involved in the assessment of inelastic limit state building responses will be modelled and assessed. The fragility functions associated with multiple demands at different mean wind speeds and directions will be evaluated, and will be further integrated with the joint probability distribution of wind speed and direction for evaluation of building system reliability. The directionality effect of wind climate and aerodynamics on inelastic building performance will be evaluated for better building design to wind.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.