NEHRP Clearinghouse
- Title
- Strengthening Methodology for Lightly Reinforced Concrete Frames-I.
- File
- PB93161354.pdf
- Author(s)
- Phan, L. T.; Todd, D. R.; Lew, H. S.
- Source
- February 1993, 112 p.
- Identifying Number(s)
- NISTIR-5128
- Abstract
- An analytical method for evaluating the inelastic dynamic structural response of lightly reinforced concrete (RC) frames strengthened by infilled shear walls was developed. The method consists of the development of hysteresis failure models for existing and strengthened RC frames and the incorporation of the models into computer program IDARC for use in analytical study. The hysteresis models were developed by, first, using the system identification techniques to characterize the load-deformation histories of fifty-five RC frame tests in terms of the stiffness degradation parameter alpha, the strength degradation parameter beta, and the pinching parameter gamma. Next, multi-variable regressions were performed to relate alpha, beta, gamma as functions of the specimen's material and geometric properties and reinforcement parameters. The results of the analyses showed that (1) hysteresis models developed using one-story, one-bay frames can be incorporated into IDARC for the analysis of frames with more than one-story height, and (2) reasonable predictions of structural behavior, both in terms of ultimate load capacity and in absorbed energy on the per cycle basis, can be achieved using the hysteresis models. Thus, in the present form, the hysteresis models can be used in parameter study to assist in the design of strengthening of RC frame structures.
- Keywords
- ; Reinforced concrete; Framed structures; Deformation; Mechanical hysteresis; Mathematical models; Walls; Dynamic response; Concrete structures; Earthquake engineering; Regression analysis; Stiffness; Design analysis; Loads (Forces); Reinforcement (Structures); Dynamic structural analysis