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.

Currently, Development of high strength reinforced concrete HSRC applications worldwide is going faster than the researches on it. Where, the shear mechanism of deep beams without stirrups still fully not understood due to its complicated behavior and conditions. In this paper, a comparative study on the shear mechanism of RC deep beams by considering values of current experimental shear strength and those calculated by international design approaches; ACI, CSA & FIB and also by the equations proposed by Sudheer, Zararis, Bazant, Zsutty, Russo and Shah. Eighteen simple span HSRC deep beams , practical size, without stirrups were tested under monotonic two point loads at the mid span to examine the contribution of various parameters on the shear capacity of deep beams. f’c=80 MPa, (ρs%) three values of main steel ratio (0.73%,1.21% &1.83%), (a/d) shear span to effective depth ratio ( 2,1.5 &1) and constant beam width for all tested beams “b= 250” mm were selected to mainly study the shear capacity and behavior of HSRC deep beams, where typical shear failure can be anticipated. As a conclusion of this paper, ACI and FIB code provisions for shear in High strength concrete (HSC) are safe for use with the exception that CSA should be used with care. Despite numerous studies, there is still a need to develop a clear understanding of the shear behavior of practical size of HSRC deep beams without web reinforcement. Therefore, this experimental program was arranged to evaluate the shear behavior and to increase the shear database on HSRC deep beams.

Currently, there is no general agreement on a theory describing the response of reinforced concrete members without web reinforcement. Many structural systems rely on design is usually performed using empirical or semi-empirical expressions provided by codes of practice that do not consider the influence of many governing parameters. In this paper, a comparison between values of current experimental shear strength and those of various international design approaches have been calculated and analyzed on 18 simple span HSRC deep beams without web reinforcement were tested under monotonic two point loads at the mid span to examine the contribution of various parameters on the shear capacity of HSRC beams like; fcu=60 MPa, three values of tension reinforcement (0.73%,1.21% &1.83%) and shear span to effective depth ratio ( 2,1.5 &1) were selected to mainly study the behavior of deep beams, where typical shear failure can be anticipated.

Currently, there is no general agreement on a theory describing the response of reinforced concrete members without web reinforcement. Many structural systems rely on design is usually performed using empirical or semi-empirical expressions provided by codes of practice that do not consider the influence of many governing parameters. In this paper, a comparison between values of current experimental shear strength and those of various international design approaches have been calculated and analyzed on 18 simple span HSRC deep beams without web reinforcement were tested under monotonic two point loads at the mid span to examine the contribution of various parameters on the shear capacity of HSRC beams like; fcu=60 MPa, three values of tension reinforcement (0.73%,1.21% &1.83%) and shear span to effective depth ratio ( 2,1.5 &1) were selected to mainly study the behavior of deep beams, where typical shear failure can be anticipated.

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