92-0022 IDARC Version 3.0: A Program for the Inelastic Damage Analysis of Reinforced Concrete Structures S.K.Kunnath, A.M.Reinhorn, R.F.Lobo 1992 University of Central Florida and University at Buffalo 144 PB93-227502 15 This report summarizes significant modeling and program enhancements to the computer code, IDARC (see NCEER-87-0008) for inelastic damage analysis of reinforced concrete frame-wall structures. As described here, IDARC is extended to include members with tapered cross-sections and the ability to specify different envelope characteristics at each end of the member. In addition, it is now able to handle moment releases at either end of a member to model perfect hinge connections. Two new element types are available: a circular column element with circumferential arrangement of longitudinal reinforcement and spiral hoops; and an inelastic discrete spring element which can be used to model nonlinear flexible connections, or indirectly, the effect of bar pull-out and joint distortions. P-Delta effects are now included in the step-by-step analysis, and a single-step correction to control unbalanced forces during event transition is incorporated. Also, it is now possible to specify applied force or displacement histories, typical in laboratory testing of components and subassemblages. The computation of damage indices has been considerably enhanced. Numerous input and output enhancements have also been incorporated. The program is validated using several available experimental results of dynamic and quasi-static testing of components, frames and model structures. Several sample problems are included, along with corresponding IDARC data files. A User Manual for the new version of the program accompanies this report. IDARC, Frame Wall Systems, Computer Programs, Reinforced Concrete Structures, Inelastic Response Analysis, Damage Analysis, and Case Studies.