Inelastic Analysis Of 3-D Mixed Steel And Reinforced Concrete Seismic Building Systems


This paper presents partial results of a NSF research project for studying the response behavior of inelastic building systems subjected to the simultaneous input of static loads and multicomponent earthquake motions that can be applied in any direction of the structural plan. The analysis includes the secondorder moment resulting from the gravity load and the vertical ground motion. The building systems may have elevator cores, floor diaphragms, and shear walls of reinforced concrete as well as steel beams, columns, and bracings. The material behavior of the steel members is based on the Ramberg-Osgood hysteresis loop with the consideration of the Bauschinger effect. Takeda's model is employed for the reinforced concrete elements. The system stiffness and geometric matrices, and the numerical integration procedures are developed consistantly with the building characteristics that each floor has dynamic degrees of freedom associated with the axial displacements of the columns and one torsional and two transverse displacements at the mass center. Thus, computation efficiency can be achieved by eliminating structural joint rotations from floor to floor with only the displacements associated with the lumped masses left for the motion equation. The yielding surface of a steel member is based on the nonlinear interactions and the von Mises yield criterion. A computer program, INRESB-3D, has been developed for the inelastic response behavior of (1) the transverse, vertical and torsional movements of a structure; (2) the internal moments and their associated rotations of the members; (3) the energy absorption characteristics of a structure; and (4) the requirement of the ductility factors and the excursion ratios of various building systems. Included in the paper is an example of unsymmetric eight-story building with steel columns and a concrete wall. © 1981.


Civil, Architectural and Environmental Engineering

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version


File Type





© 2023 Elsevier, All rights reserved.

Publication Date

01 Jan 1981