Workshops: Reliability Evaluation of Wind-Excited Structures with Controlled Inelasticity

Seymour Spence
Assistant Professor
University of Michigan, Detroit

Performance-based wind engineering is becoming a more prevalent analysis and design philosophy, as attested by the recent development and publication (August 2019) of the American Society of Civil Engineers (ASCE) Prestandard on Performance-based Wind Design (PBWD). For maximum benefit, i.e., greatest increase in performance, this document recommends the use of performance assessment models that are based on explicit evaluation of the reliability of the main wind force-resisting system (MWFRS) that is allowed to experience controlled inelasticity. One of the procedures suggested for carrying out this evaluation is based on the concept of dynamic shakedown of the MWFRS.

Focus is given primarily to introducing the concept of dynamic shakedown and how this state of an inelastic system ensures safety against low-cycle fatigue, ratcheting and plastic collapse, which are considered the fundamental potential failure mechanisms for a structural system subject to long duration wind loads. Secondarily, it is illustrated how this concept can be housed within a stochastic simulation framework that accounts not only for the record-to-record variability of the wind loads (through stochastic models informed by wind tunnel data), but also for all other uncertainties necessary in order to provide reliability estimates consistent with the requirements of the ASCE Prestandard on PBWD. This framework, which was developed in collaboration with Magnusson Klemencic Associates (MKA), is illustrated on a full-scale architype building designed by MKA for the ASCE Task Committee on Performance-based Wind Engineering.