Influence of Shear Reinforcement on Reinforced Concrete Continuous Deep Beams

Reinforced concrete deep beams are used in structures as
load distribution elements such as transfer girders, pile caps,
and foundation walls in tall buildings. Although these members
commonly have several supports, extensive experimental
investigations have brought simple deep beams into focus.
The behavior of continuous deep beams is significantly
different from that of simply supported deep beams. The
coexistence of high shear and high moment within the interior
shear span in continuous deep beams has a considerable
effect on the development of cracks, leading to a significant
reduction in the effective strength of the concrete strut,
which is the main load transfer element in deep beams.
1
Indeed, few experiments
1-3 were carried out on continuous
deep beams of shear span-to-overall depth ratio (a/h) greater
than 1.08. The results of simple deep beams tested by Tan et al.
4
and Smith and Vantsiotis,
5 however, showed that the relative
effectiveness of horizontal and vertical shear reinforcement
on controlling diagonal cracks and enhancing load capacity
reversed for deep beams having an a/h less than 1.0, that is,
horizontal shear reinforcement was more effective for an a/h
below 1.0, whereas vertical shear reinforcement was more
effective for an a/h lager than 1.0. Therefore, a reasonable
evaluation of the influence of shear reinforcement on
continuous deep beams having an a/h less than 1.0 requires
further investigation.
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