Flexural strength-ductility performance of flanged beam sections cast of high-strength concrete

Abstract

Flanged sections are often used for long-span concrete beams to maximize their structural efficiency. However, although for the same sectional area a flanged section could render a higher flexural strength, it would also lead to a lower flexural ductility, especially when heavily reinforced. Thus, when evaluating the flexural performance of a beam section, both the flexural strength and ductility need to be considered. In this study, the post-peak flexural behaviour of flanged sections is evaluated by means of an analytical method that uses the actual stress-strain curves of the materials and takes into account strain reversal of the tension reinforcement. From the numerical results, the flexural strength-ductility performance of flanged sections is investigated by plotting the strength and ductility that could be simultaneously achieved in the form of design graphs. It is found that (1) at the same overall dimensions and with the same amount of reinforcement provided, a flanged section has lower flexural ductility than a rectangular section; (2) at the same overall dimensions, a flanged section has inferior strength-ductility performance compared to a rectangular section; and (3) at the same sectional area, a flanged section has better strength-ductility performance compared to a rectangular section. Copyright © 2004 John Wiley & Sons, Ltd.