Experimental Study on Shear Bearing Capacity of Joints in Precast Concrete Segmental Beam

Through the shearing tests of three types of pure shear specimens with keyed dry joint, keyed epoxied joint and dry flat joint, the shear bearing capacity of joint surface in precast concrete segmental beam was studied. The results show that the measured shear bearing capacity shows linear variation with the compressive stress of the joint for the specimens with keyed dry joint and keyed epoxied joint, and all the shear failure modes are brittle failure in the limit state. The failure surface of the specimen with keyed dry joint appears at the root of shear key, and that of the specimen with keyed epoxied joint appears on the joint surface. That is, the shear failure occurs simultaneously on the joint surface and shear key. Adding shear keys to dry flat joint can significantly improve the shear bearing capacity. The epoxy resin adhesive has a certain effect on increasing the shear bearing capacity of keyed dry joint, and both the shear bearing capacity of joints increases with the increase of the compressive stress of joint surface. The calculation formula of shear bearing capacity for joints given in American Guide Specifications for Design and Construction of Segmental Concrete Bridges is partial to safety. The reduction coefficient for dry joint is suggested to be 0.80. The shear bearing capacity of keyed epoxied joints in fully bonded internal segmental beam is calculated as dry joints, and the shear strength reduction is no longer considered. © 2021, Editorial Department of China Railway Science. All right reserved.