Abstract:
This work proposes alternative analytical method for the prediction of ultimate load
carrying capacity of reinforced concrete deep beams to that of strut-and-tie method.
Three categories each category with five reinforced concrete deep beam specimens of
shear span to depth ratio 1.00, 1.25, 1.50, 1.75 and 2.00 are studied. The beams are
studied first analytically and then results from analytical method are validated by using
nonlinear finite element analysis. It is confirmed that the result from analytical method
for ultimate load capacity is in best agreement with nonlinear finite element analysis and
this shows that the analytic approach used to predict ultimate load capacity is applicable.
In the next session of the work a case study is carried out to determine the influence of
some parameters on the predictive capacity of the proposed analytic method. Generally
the effect of main reinforcement and web reinforcement ratios are covered in the
parametric study part. For all categories the results from parametric study indicates that
the increase in main reinforcement ratio has showed significant increase up to ultimate
load and further increase will not affect the ultimate load capacity. In the same manner
the increase in web reinforcement ratio either vertical or horizontal reinforcement ratio
for all categories resulted in a linear load capacity increase especially for deep beams
with shear span to depth ratio 1.00, 1.25 and 1.50. But for deep beams with shear span to
depth ratios of 1.75 and 2.00 significant increases in load carrying capacity is not
recorded. Also the diagrams for ultimate load versus vertical and horizontal
reinforcement ratio for all categories indicate that vertical web reinforcement ratio is
effective in increase ultimate load carrying capacity than for the same increase in
horizontal web reinforcement ratio.
