Time-Varying Evolution Behaviors of Steel-Concrete Composite Girders with Differentiated Connectors

To improve the cracking resistance of a concrete slab in the hogging moment region, a new concept called uplift-restricted and slip-permitted (URSP) connection technology has been proposed. Several studies have been conducted on URSP connectors, but investigations into the time-varying evolution behaviors of composite beams with URSP connectors are still lacking. In this paper, three types of elaborate finite element models of composite girders with differentiated connectors and different construction methods were established. Simulation of the concrete shrinkage and creep effect was realized using a user subroutine based on an improved rate-type formulation. The performances of the composite girders in three schemes were analyzed and compared in both the construction and service stages. The results demonstrated that the URSP connection technique can effectively increase the prestressing efficiency and decrease the tensile stress of the concrete induced by dead loads and vehicle loads. With an increasing service time, the concrete shrinkage effect will enhance the advantage of the URSP connection technique, and the creep effect will reduce this advantage. Finally, parametric analyses were conducted, and a value of 0.2 is recommended for the URSP length ratio to promote practical applications.