Experimental research on shear resistance performance of fabricated reinforced concrete layered beams

Abstract

The construction of prefabricated beams includes two steps: prefabrication and cast in-situ. However, for the bearing beam, the shear stress on the joint surface of these two parts may be large. This is detrimental to the shear resistances of layered beams. To evaluate the shear resistance performances of such layered beams, three different influencing factors—the ratio of the precast layer height to the beam height, shear-span to depth ratio, and the treatment method of new and old concrete interface—were considered, and shear resistance tests of 9 groups of beams were carried out. The failure mode, carrying capacity, deflection, and strain value of each test beam were analyzed. The results show that the shear bearing capacity of layered beams decreases by 34.12% with the increase of shear-span to depth ratio, and with the increase of the ratio of precast layer height to beam height, the shear bearing capacity of layered beams decreases by 14.17%. The shear bearing capacity of the layered beam with steel bars inserted in the vertical direction of the new and old concrete interface is about 8.43% higher than that of the layered beam without steel bars. According to the test results, the formula for calculating the shear bearing capacity of layered beams considering the layered height ratio and shear-span to depth ratio was proposed. At the same time, the interface resistant shear design method concerning reinforced concrete layered beams is proposed.