Title: Behavior of Reinforced Concrete Beams with a Shear Span to Depth Ratio Between 1.0 and 2.5

Author(s): Michael D. Kotsovos

Publication: Journal Proceedings

Volume: 81

Issue: 3

Appears on pages(s): 279-286

Keywords: beams (supports); bearing capacity; failure; finite element method; loads (forces); reinforced concrete; shear strength; span-depth ratio; structural analysis; tensile stress.

DOI: 10.14359/10684

Date: 5/1/1984

Abstract:
A finite element analysis of under- and over-reinforced concrete beams subjected to two-point loading indicates that placing shear reinforcement in the middle rather than in the shear span results in both higher load-carrying capacity and ductility when the shear span to depth ratio is between 1.0 and 2.5. It is shown that this behavior is due to collapse of the beams by "splitting" of the compressive zone of the middle span rather than "crushing" of the loading point region as is generally thought. Splitting is caused by tensile stresses that develop in the compressive zone from the interaction of adjacent concrete elements subjected to different states of stress. In fact, for all cases investigated, this interaction is found to cause collapse before the ultimate strength of concrete in compression is attained anywhere within the beams.