Behaviour of Stud Shear Connectors Subjected to Bi-Directional Cyclic Loading

Abstract

Almost all stud shear connectors in composite steel-concrete bridge beams are subjected to bi-directional cyclic loading at some stage during the fatigue life of the structure. In the assessment of an existing structure, it is desirable to predict the extent of fatigue damage experienced by the stud shear connectors as accurately as possible as this component of the structure can not be visually inspected. However, very little research has been carried out to quantify the fatigue behaviour of stud shear connectors subjected to bi-directional cyclic loading. This paper presents a new push-pull specimen that was developed to provide a better understanding of the bidirectional cyclic fatigue behaviour of stud shear connectors. The tests confirmed that for a given range of load, the fatigue life of connectors subjected to bi-directional cyclic loading is longer than those subjected to unidirectional loads only, and that the strength and stiffness of the connectors reduce immediately upon cyclic loading and continues to do so throughout the fatigue life. It was also shown that the rate of increase in slip per cycle is constant over most of the fatigue life with a rapid increase near the end so that, if monitored, can be used to provide adequate warning of failure.

Keywords

stud shear connectors bi-directional cyclic fatigue loading composite steel-concrete bridge beams

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