Title:
Flexural Behavior of High-Strength Concrete Beams
Author(s):
M. A. Mansur, M. S. Chin, and T. H. Wee
Publication:
Structural Journal
Volume:
94
Issue:
6
Appears on pages(s):
663-674
Keywords:
beams; deflection; ductility; flexure; high-strength concrete;
moment-curvature relationship; rectangular stress block; strain; stress;
tests
DOI:
10.14359/9726
Date:
11/1/1997
Abstract:
The results of eleven reinforced high-strength concrete beams tested in flex-ure are presented. All but one beam was over-reinforced, and the compres-sion zone of the beams was confined with either ties or fibers, or left unconfined. Test results indicate that the brittle type of failure in over-reinforced concrete beams can be arrested by introducing transverse ties or discrete steel fibers in the compression zone. For such a beam, both ultimate strength and ductility can be enhanced by increasing the concrete strength. Ductility also increases with an increase in the volume fraction of confining ties, but up to a certain limit. The stress-strain curves for concrete in compression obtained from the flexural tests are remarkably similar to those generated from uni-axially loaded specimens. The analysis based on the usual flexural theory, but using the stress-strain curves for uni-axially loaded speci-mens, gives close predictions of the experiment data on moment-curvature relationship and ultimate moment capacity of the beams. Evaluation of the present test data and the results from available literature show that Whitney’s rectangular stress block can be used in the strength design of high-strength concrete flexural members.