Title: Experimental and Analytical Modeling of Unbraced Multipanel Concrete Frames

Author(s): J. S. Ford, D. C. Chang, and J. E. Breen

Publication: Journal Proceedings

Volume: 78

Issue: 1

Appears on pages(s): 21-35

Keywords: axial loads; bending moments; columns (supports); frames; columns; reinforced concrete; research; structural analysis; tied columns.

DOI: 10.14359/6908

Date: 1/1/1981

Abstract:
This paper summarizes the physical and analytical modeling of a series of unbraced multipanel concrete frames. These frames had four columns of unequal stiffnesses and were loaded with beam, column, and lateral loads. The objectives of the test series were to study the behavior and redistribution capability of highly indeterminate concrete frames under realistic loading corn bina tions, to assess the applicability and accuracy of current design procedures, and to develop correct analytical modeling techniques for the nonlinear analysis of frames. This paper documents the experimental test procedures, the data interpretation methods, and the nonlinear analysis program used to model the frames. The data interpretation and nonlinear analysis relied heavily on axial load-moment-curvature (P-M-o) relationships , verified in a companion series of isolated columns tested under controlled deformation loading. The analytical modeling procedure approximated the demonstrated ductile rotations in critical column regions by inserting equivalent plastic hinges. Overall, the analytical program accurately predicted the load-deflection behavior, yield locations, sequence of yielding, and load levels at yielding.