SIMPLIFIED REFERENCE SYSTEMS IN THE ESTABLISHMENT AND APPLICATION OF DISPLACEMENT-BASED SEISMIC DESIGN CRITERIA

摘要

The adoption of displacement-based seismic design criteria requires the development of seismic design acceptance criteria that are directly based on lateral displacements and distortions. In order to take full advantage of those benefits it is important to count with methods for the prediction of the nonlinear dynamic response of structural systems that are both sufficiently accurate and easy to apply under conditions typical of structural design practice. It is also necessary that the acceptance rules that are adopted are optimum in the sense that they minimize the sum of the initial construction costs and the present value of the expected future expenditures, including damage and failure consequences, as well as repair and maintenance costs. This paper presents a method for the estimation of nonlinear seismic responses of buildings and of the corresponding expected damage costs. Response estimates are obtained with the aid of a simplified reference system, a lateral configuration function derived from a pushover analysis, and a set of correction factors. The latter account for the uncertainties associated with the response of the simplified reference system and with the local deviations of the actual displacements with respect to those derived from the pushover analysis. The method proposed is applied to the development of optimization studies for the establishment of design acceptance criteria. The problems associated with the transformation of the results of the optimization studies into practical design rules are discussed.