EXPERIMENTAL RESEARCH ON FLEXURAL PERFORMANCE OF I-BEAM-UHPC COMPOSITE BEAM WITH CORRUGATED STEEL WEBS

To investigate the bending performance of I-steel composite beams with corrugated steel webs in the form of laminated slabs (using ultra-high-performance concrete, UHPC, for the upper layer and slots, and normal concrete, NC, for the lower layer), bending tests were conducted on I-beam-UHPC composite beam with corrugated steel webs (referred to as CSRCU) and I-beam-NC composite beam with corrugated steel webs (referred to as CSRC). The failure characteristics, bearing capacity and strain development patterns of the test beams were explored. A parameter sensitivity analysis was conducted based on the experiments to investigate the effects of shear connection degree, the ratio of NC layer thickness to UHPC layer thickness and the equivalent thickness of the laminated layer on the mechanical properties of composite beams. Practical recommendations for reasonable parameter values were also provided. The results show that the damage characteristics of the two groups of test beams are similar. The high strength of UHPC reduces the damage range in the bridge deck of the CSRCU test beam, and the application of UHPC in slot prevents the delamination between steel and concrete. The CSRCU test beam exhibits higher bearing capacity and superior ductility compared with the CSRC test beam. At the limit state, the strain distributions in the bridge decks of the two test beams and the upper and lower flange plates of the steel beams are linear, consistent with the assumption of plane section. The corrugated steel web of the CSRCU test beam reaches the yield strength across the entire section height, and the web of CSRC test beam reaches the yield strength within half the height range. The bending contribution of corrugated steel webs cannot be ignored. CSRCU composite beams and CSRC composite beams can meet the stress requirements when the shear connection degree reaches 0.75 and 0.85, respectively. It is suggested that the reasonable thickness ratio of the NC layer to the UHPC layer in CSRCU composite beams be in the range of 1.5 to 2.75. Compared with the NC bridge deck, the thickness of the UHPC laminate can be reduced by about 20%.