Reinforced concrete (RC) deep beams mainly fail in shear, brittle
and sudden in nature can lead to calamitous consequences. Thence, it is critical
to determine the shear characteristics of RC deep beams accurately due to
involving many parameters at same time. Some of the recent researches have
shown that current equations for predicting ultimate shear strength are
non-conservative when applied to high strength concrete (HSC) beams as well
as some of design codes provisions. There are different approaches for analyzing
the behavior of beams in shear.
In this paper, a semi-empirical approach is adopted in which a database of
existing experimental and literature results of deep beams, d > 300 mm &
d < 300 mm, failing in shear under two point loads statically at mid-span, was
constructed. The database, 725 deep beams, was used to propose two simplified
shear equations using multiple regression analysis, IBM-SPSS-Statistics, to find
out and evaluate the most important factors affecting the ultimate shear strength
formulating them in a suitable predictive equation for the ultimate shear strength
of deep beams without web reinforcement (stirrups). The test database covers a
wide range of individual parameters as: cylindrical concrete compressive
strength (20


f′c


104 MPa), longitudinal main steel reinforcement ratio
(0.17%


qs%


6.64%), effective depth of deep beams “d” (127–1000 mm),
shear span to effective depth ratio (1


a/d


2.5), Beam width “b”; b/d < 1,
where all database from literature were based on two point loading.
This paper concluded that, the proposed equations seem to predict the ultimate
shear strengths well, conservative and give lower coefficient of variation
“COV” and smaller range of results when compared with the available methods
of design; ECP203-2007, ACI 318-14, CSA, and BS8110 codes and other
equations proposed by Sudheer Reddy, Zararis, Bazant, Zsutty and Shah.