This paper summarize and analyzie the shear charactaristics of tested beams according to
provisions of ACI & JSC codes which both of them specifie the shear strength of deep beams
based on the first diagonal crack strength of normal strength concrete NSC beams without taken
into account the beam size effect. Hence, it is substantial to evaluate the applicability of JSCE &
ACI shear design equations to high strength reinforced concrete (HSRC) deep beams with main
steel ratio less and more than 1% with considering beam size effect or not. f’c=60 MPa, three
values of main reinforcement, (ρs%), (0.73,1.21 &1.83) and shear span to overall depth ratio,
(a/h), ( 0.84,0.87,1.3 &1.7) were selected to study the shear characteristics of 18 simple span
deep beams without stirrups. The increase in overall depth (h) under the same a/h=1.3&1.7, led
to more brittle failure with wide diagonal cracks. HSRC deep beams exhibited more remarkable
size effects with regard to brittle behavior. It was also shown that the ACI code gives similar
safety factors on the shear strength at the first diagonal crack of HSRC deep beams, but do not
specify a high enough safety factor on their ultimate strength due to the size effects.