Abstract:In order to develop the calculation method for the tensile strength of headed studs widely used in steel-concrete composite bridges, four groups of pull-out specimens with different stud heights were tested. The overall stud heights used in the four groups were 100mm, 200mm, 300mm and 400mm, respectively. Based on the test results, the effect of stud height on failure mode, tensile strength and peak separation were investigated. Tensile strength equations specified in exiting codes (ACI 318-08, PCI 5th and CEB-ECCS) were evaluated based on 93 test data of this study and other researches. In addition, constraint equations for preventing the brittle failure modes of stud pullout, side-face blowout and concrete breakout were developed. Finally, calculation method of the ductile tensile strength of headed studs was proposed. The results indicate that the tensile strength and peak separation of the specimens failed due to steel failure are 1.5 times and 5.8 times as large as those of the specimens failed due to concrete breakout failure, respectively. The strength equations given by ACI 318-08 give more accurate predictions than those in the other codes. The minimum concrete compressive strength, minimum distance from stud center to concrete edge and stud height-diameter ratio are employed as constraints to prevent the brittle failure modes. The proposed calculation method of the ductile tensile strength of headed studs can provide guidance when designing headed studs under tension force.
