Civil Engineering Department award a Ph.D. 

Civil Engineering Department at the University of Technology awarded a Ph.D. in structural engineering discipline to the student (Hind Talib Jaber) about:

" Influence of Size on The Shear Strength of Reinforced Concrete Beams"

During recent decades the construction of reinforced concrete structures has developed greatly and as a result, the cross-sections of these concrete members are being expanded. Research has indicated that as the depth of concrete beams is increased, the final shear stress is expected to decrease. Volume effect is a phrase used to describe this trend.

Although both the American Building Code ACI 318M-19 and the British Standard BS 8110-1: 1997 have taken into account the effect of size, their effect was conflicting and opposite in the decrease in the final shear strength values. As a result, a practical and theoretical study was conducted to study the discrepancy between the effect of size on the failure of shear strength for both ACI and BS, and to propose an equation to calculate the final shear strength that takes into account the effect of size based on a qualified shear database for 954 reinforced concrete beams, of which 15 are from the current research. And 939 thresholds from 79 other researchers.

The experimental program included casting and testing sixteen simple reinforced concrete beams with different cross-sections and without shear reinforcement under the influence of two concentrated loads to the point of failure for the purpose of evaluating the final shear strength of concrete. Experimental results showed that all tested beams failed to shear, except for one (failed with bending) where diagonal tensile failure was observed. While the increase in the size of the cross-sections of the beams led to a decrease in the final shear stress in different proportions. And by comparing the results of the shear database using four different formulas (ACI-14, ACI-19, BS-97 and, Proposed equations), it was found that the proposed equation had the lowest coefficient of variation, which was equal to 24,752. Moreover, none of the equations appear (ACI-14, ACI-19) nor does BS-97 equation make any difference in shear strength with changing width of the reinforced concrete models used. This means the efficiency of the proposed equation against the existing three methods.

The discussion committee consisted of: -

-  Prof. Dr. Hisham Mohamed Ali / the head.

-  Prof. Dr. Adel Abdul-Amir Mohamed / member.

- Assist. Prof. Dr. Sarmad Shafiq Abdul-Qader / member.

- Assist. Prof. Dr. Diaa Hamoudi Mohamed / member.

- Prof. Dr. Qais Fouad Sarsam / supervisor.