ISDP: Integrated Approach to Seismic Design of Reinforced Concrete Structures

Limitations of present procedures for the design of reinforced concrete structures to withstand seismic loads are discussed. An integrated seismic design procedure (ISDP) is proposed, the main features of which are (1) The automatic selection and scaling of design ground motions given the earthquake magnitude, epicentral distance, and the type of overlying soil strata; (2) prediction of the inelastic behavior of reinforced concrete elements when subjected to random lateral loads up to and including failure; and (3) calculation of cumulative damage that is directly correlated to observed states of damage from laboratory tests of reinforced concrete elements. The analytical tools required to implement these capabilities are discussed. New seismic design criteria are proposed, which are based on acceptable damage indices as functions of earthquake energy content and structural importance. The proposed seismic design approach is demonstrated by means of a practical example involving the seismic retrofit of a spiral reinforced bridge column. This example incorporates new and existing analytical tools, and demonstrates the feasibility of the proposed approach.