Deterioration in Strength of Stud Connectors in Composite Bridge Beams

Abstract

It is a common practice for the stud shear connections in composite bridge beams to be designed for both strength, to resist the ultimate loads, and for endurance, to resist the numerous applications of the serviceability loads. These two calculations are normally done independently of each other and the upper bound of the two connector distributions is used in design. This technique therefore assumes that there is no interaction between the strength of the shear connection and the fatigue loads. However, new experimental tests now show that the monotonic strength of stud shear connectors reduces under fatigue loads, and hence present design techniques do not simulate the actual behavior of the shear connection. A method is given of designing the shear connection to allow for the reduction in the monotonic strength due to fatigue loads that can also be used to estimate the residual strength of the shear connection in existing bridge beams.