Upper Limit of Aerodynamic Forces for Inelastic Wind Design

Abstract

Due to the increasing tendency to construct taller and more slender buildings, the need to address aerodynamic and induced dynamic forces (inertial forces) under both service and strength-level wind loads has become more important. Currently, application of performance-based wind design (PBWD) to reduce induced dynamic forces applied through the acceptance of inelastic deformation is permitted as an alternative design approach, in which wind load can be reduced with respect to the yield strength and ductility of the structure. However, reduced wind load smaller than aerodynamic forces may not ensure proper inelastic wind design. The results of this study indicate that to avoid huge ductility demand due to damage accumulation, the yield strength for structural systems with zero-to-modest post-yield stiffness must be larger than the aerodynamic forces. Moreover, due to uncertainty in the number of occurrences of peak aerodynamic loads applied to a structure during a wind event, it would be advisable for systems with large post-yield stiffness to consider upper limits of aerodynamic forces.