The objective of this paper is to experimentally and analytically estimate the influence of inclined
reinforcement placed above and below web openings having different shapes in reinforced concrete
(RC) deep beam. Twenty RC deep beams had the same overall geometric dimensions were tested
under two-point top loading. Test variables included amount of inclined reinforcement, opening
shape (circular, square, rectangular and relatively new type rectangular with fillet edges) and shear
span-to-depth ratio. The relationship between the amount of inclined reinforcement and the opening
size was expressed as the effective inclined reinforcement factor. As this factor was increased, the
behavior of tested beams improved, where the crack width and its development decreased, and the
ultimate load increased. The improvement rate of ultimate load with increasing effective inclined
reinforcement for beams with rectangular openings having fillet edges was higher than that with
sharp edges. Beams with opening having square, circular, or rectangular with fillet edges shapes
and having effective inclined reinforcement ratio above 0.085 and 0.091 under shear span-to-depth
ratio 1.0 and 0.6, respectively had higher ultimate load than that of corresponding solid beams. The
effect of inclined reinforcement on enhancing the behavior of deep beam with opening increased as
the shear span-to-depth ratio decreased. The ultimate load of tested beams was estimated using
upper-bound analysis of the plasticity theory and compared with the test results. It is shown that the
prediction has a consistent agreement with the experimental results. |
