Experimental Study of Steel Keyed Joints in Precast Concrete Segmental Bridges Under Direct Shear Loading

Abstract:

Eight groups of “Z” joint specimens were designed to conduct direct shear tests on steel keyed joints. Taking shapes，sizes，numbers of steel keys and joint type as experimental parameters， the mechanical properties of joints were studied. The results show that the stiffness of epoxied joints is superior to that of the dry joints. The epoxied joints have an ultimate shear strength of 151.39%， and 69.68% higher than dry joints， for 1 and 2 steel keys， respectively； while the failure of the epoxied joints is found to be more sudden and brittle. Adding 1 or 2 steel keys to a flat joint， shear strength can be increased 43% and 41.58% for epoxied joints， 3.81 times and 6.06 times for dried joints respectively. The failure modes of the dry joint are determined by the cracking strength of concrete and the shear strength of the steel key， while the epoxied joint appears direct shear failure. When the steel key epoxied joint occurs direct shear failure， the shear resistance is provided by the steel key and friction， and its mechanical properties are similar to the steel key dry joints.