Strengthening Methodology for Lightly Reinforced Concrete Frames-I.
Strengthening Methodology for Lightly Reinforced
Concrete Frames-I.
(2442 K)
Phan, L. T.; Todd, D. R.; Lew, H. S.
NISTIR 5128; 108 p. February 1993.
Available from:
National Technical Information Service
Order number: PB93-161354
Keywords:
frames; reinforced concretes; analytical; dynamic
analysis; experimental; hysteresis models; infilled
walls; system identification; multi-variable regression
Abstract:
An analytical method for evaluating the inelastic
dynamic structural response of lightly reinforced
concrete (RC) frames strengthened by infilled shear
walls was developed. This 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, the strength degradation
parameter, and the pinching parameter. Next,
multi-variable regressions were performed to relate as
functions of the specimen's material and geometric
properties and reinforcement parameters. The empirical
expressions resulted from these regressions are the
hysteresis failure models. The models were validated by
analyzing a one-story, one-bay infilled frame, tested by
Aoyama et al., and a three-story, one-bay infilled frame
tested by Higashi et al. 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.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899