Performance Based Design: A Rational Approach for Seismic Analysis and Design

Traditionally, the design of structures against earthquakes has followed a strength based approach using linear elastic analysis, this approach however is not entirely rational since nonlinear behavior is an essential characteristic of the structure under seismic loading to achieve ductility and economy in design. The current building codes account for inelastic behavior of the structure using response modification factors and general detailing rules, then it’s implied that satisfying these set of rules will result in safe design with no collapse of the structure, however this is not explicitly verified and the seismic performance is not directly determined, thus, the need for more rational approach for seismic design is recognized leading to the development of performance based seismic design which explicitly evaluate the structure performance during earthquakes, this rational procedure allows for the incorporation of multiple performance levels for different levels of ground shaking while still fulfilling the minimum codes criteria for life safety, this is achieved using nonlinear analysis in addition to displacement and capacity based design principles. In this regard, this paper presents the state of art of performance based seismic design starting by reviewing the current practice of seismic design and how does it relate to structure performance.