Abstract:
The uplift-restricted and slip-permitted (URSP) connector technology is a new composite technology which achieves the purpose of reducing the tensile stress in concrete slab by releasing part of the composite action in the negative moment region. It is found that the stress is coupled between the slip-restricted area and slip- permitted area, which has a significant impact on the force transfer mechanism of URSP composite beams. Previous studies on URSP technology seldom mention similar coupling effects, which cannot accurately describe the mechanical behavior of URSP composite beams. In order to properly consider the influence brought by the coupled stress effect, this study uses continuous composite beams to carry out experimental research. Three two-span continuous composite specimens were fabricated and tested in this research. Six aspects of performance were compared and analyzed in detail, including cracking load, crack distribution and development pattern, interfacial slip behavior, deformation and stiffness, internal force redistribution and strain distribution. It is found that the URSP connector can realize the release of part of the composite action, and has a significant effect on the crack control in the negative moment region. Meanwhile, the application of URSP connectors has little effect on the stiffness, bearing capacity and strain of steel beam.