Abstract:In order to investigate the shear behavior of prestressed ultra-high reinforced concrete beams, a total of 11 prestressed ultra-high reinforced concrete beams and 4 prestressed ordinary reinforced concrete beams were tested. The experimental study addressed failure mode, load-delfection curve, ultimate load capacity and the steel strain. The test results have shown that failure mode of prestressed ultra-high reinforced concrete beams is similar with that of prestressed ordinary reinforced concrete beams. Generally, prestressed ultra-high reinforced concrete beams have better higher stiffness and ultimate load capacity, as well as shear ductility. An increase in the shear span-depth ratio or space of stirrups decreases ultimate load capacity. In addition, it has positive effect on the ultimate load capacity for degree of prestress of more than approximately 0.34. A calculating formula for shear capacity of prestressed ultra-high reinforced concrete beams with stirrups was offered. The calculation results agree well with the test conclusions. The current China code (GB 50010-2010) used for the design of prestressed ultra-high reinforced concrete beams is very unstable and the dispersion ratio is high.