Nonlinear Dynamic Response of Single-Degree-of-Freedom Systems Subjected to Along-Wind Loads. II: Implications for Structural Reliability

Abstract

Part I of the two companion papers postulated and proved the capability of self-centering systems in controlling the wind-induced damage accumulations due to long-duration along-wind loads. The present Part II paper demonstrates the benefits of ductility-based wind design in terms of economics and safety through structural reliability analysis. Initially, for self-centering systems, the ductility demands are estimated for various levels of force reduction factors, structural damping, postyield stiffness ratio, natural frequency, and energy dissipation capacity. To reduce the computational cost of structural reliability analysis, empirical equations of the mean of peak ductility demands are derived in terms of the force reduction factor and natural frequency. In the reliability estimations, two limit states, the first significant yield and incipient collapse, are considered. Both analytical and simulation techniques are used to compute the failure probabilities by considering uncertainties in both the wind load effects and capacity. Overall, the results indicate that ductile self-centering systems could be designed for reduced along-wind loads and still achieve the minimum required safety level. The results also reveal that self-centering systems designed using the linear-elastic approach but additionally detailed for ductility have a significant reserve of safety against incipient collapse.