Effects of Group Arrangement on the Ultimate Strength of Stud Shear Connection

For the design of shear connection for region of highly concentrated shear force in steel-concrete composite bridges, connection details are the most important design issues. Failure modes of the shear connection govern the ultimate strength for the design and governing design parameters can be changed. Instead of rigid shear connectors, this paper deals with the group stud shear connection for the precast decks. Shear pockets for stud connectors arise difficulty in the details of precast decks. Push-out tests were conducted to evaluate the ultimate strength according to the expected failure modes. Main parameters of the test were stud spacing, reinforcement details and stud diameter. Test results showed that current design provisions for the stud connectors can be used for the design of group stud shear connection when the design requirements on the minimum spacing of studs are satisfied and the splitting failure of concrete slab is prevented. An empirical equation was proposed to consider the effect of stud spacing when the spacing is less than the minimum requirement. Fatigue tests showed that the group stud connectors with spacing of more than three times of diameter has similar fatigue life with current design codes. Based on the test results, design recommendations for shear connection in a precast deck bridge were derived.