In this article, a strut-and-tie model (STM) is proposed for predicting the
ultimate shear capacity of fiber reinforced polymers (FRP)-strengthened
reinforced concrete deep beams. The proposed STM accounts for the effect
of concrete strength, FRP ratio, ratio of main steel, horizontal and vertical
stirrups ratio and shear span-to-depth ratio. The ultimate shear predictions
of the proposed model are validated with 55 test results from the literature.
The comparison showed that the proposed model performs well in
predicting the ultimate shear capacity of FRP-strengthened RC deep beams.
The overall average value of the ratio between the experimental capacity
to the theoretical capacity of the proposed STM (Pu(EXP)/Pu(STM)) is of value
1.16 with a standard deviation of 0.18. Also, comparative studies between
the proposed modified STM and the STM provided by the ACI code and
other researchers in the literature are presented. Finally, FRP effectiveness
studies are performed to study the effect of many structural parameters on
the ratio between the ultimate strength for RC deep beams strengthened
with FRP materials and the ultimate strength for ordinary RC deep beams.
These parameters are FRP ratio (ƿFRP), the fiber orientation angle to the longitudinal
axis of the deep beam, material type of FRP, concrete compressive
strength (fc’) and the shear span-to-depth (a/d) ratio