The resistances of stud shear connectors with profiled sheeting
This thesis presents the study of the static behaviour of stud shear connectors welded through profiled sheeting and the fatigue resistances of the connectors in composite bridges. In the presence of profiled sheeting in a composite beam, the resistance of stud connectors to static shear is influenced by the geometry of the ribs and the position of the studs within them. This is allowed for in the existing methods by applying a reduction factor to the resistance of the stud in a solid slab, but a study of the results of 203 push-out tests showed that the influences are not taken into account properly. The reason, revealed by 16 new push-out tests with transverse sheeting and 18 with parallel sheeting, is that the existing methods do not distinguish between the various failure modes. New conceptual and mathematical models are developed with respect to the different failure modes. For transverse sheeting, up to nine parameters are involved, among which five are shown by statistic analyses to have negligible influence. Based on the other four, simpler expressions for reduction factors are derived, and the characteristic resistances (5% fractile) are given. For parallel sheeting, however, it is found that the reduction factor method used in the existing models is not suitable, because the mechanism of load transfer is different. On a whole, the new models improve the prediction of 95% of all the valid reported test results, from a range -40% to +100% to within +11%. The fatigue resistances of stud connectors in composite bridges are studied statistically using 115 sets of reported data. It is found that the testing methods have significant influence on the results, and are the reason for the discrepancies between the existing models. A new model is proposed, based on the most reliable group of data.