As is well known, in the current design codes, the shear strength of beams is calculated
based on the modified truss theory, which does not consider the effects of the flange area of T-beams.
The main objective of this paper was to gain a better understanding and enhance the experimental
database of the shear behavior of RC T-beams and illustrate the contribution of the flange to the shear
capacity of T-beams. To accomplish this aim, a specially designed experimental program was executed,
and its test results were analyzed. The main investigated variables were flange dimensions (thickness
and width) and its reinforcement (longitudinal and/or vertical). Nineteen simply supported beam
specimens were tested to failure under a load configuration made of two concentrated loads. Eighteen
specimens had T-shaped cross-sections, while one specimen had a rectangular cross-section for
comparison purposes. The items monitored during testing included the development of diagonal
cracks, concrete strains, reinforcement strains, maximum loads, and deflections. Test results showed
a notable increase in the shear strength of T-beams compared to rectangular beams with the same
web size. For the range of variables investigated, increasing the flange thickness-to-beam depth
ratio (rt) from 0.3 to 0.5 increased the shear capacity by up to 54%. In addition, increasing the flange
width-to-web width ratio (rb) from 3 to 5 increased the shear capacity by up to 19%. It was also
shown that the results of three-dimensional finite element (FE) analyses using ANSYS compared
reasonably well with the test results for all specimens. Finally, based on the test and FE results, a
simplified method that accounts for the contribution of the flange to shear capacity was proposed. |
