Abstract：In order to study the shear-cracking enhancement effect of prestressed technology to steel fiber reinforced concrete, the practical formulas were proposed for evaluating the shear-cracking capacity of unbonded steelfiber prestressed reinforced concrete beams (UPSFRCB) through the test and analysis of shearcracking strength of UPSFRCB with simply supported ends. Various factors affecting the shear-cracking strength of UPSFRCB with simply supported ends, such as the characteristic value of steel fiber and shear-span to depth ratio, were analyzed. The degrees and rules of the characteristic value of steel fiber, shearspan to depth ratio, and effective prestress force, which affected prestressed concrete beams, were also discussed. The results show that prestress and steel fiber can effectively enhance the shear-cracking capacity of reinforced concrete beams. The shear-cracking load increases with the increase of the steel fiber volume ratio and the length to diameter ratio within a certain range. The prestress can retard the occurrence of bending crack at the beam bottom of the shear span, reduce the inclination angle of the diagonal crack, and increase the height of the shear-compression zone.
2010, Vol. 31 
