Research on Flexural Test and Crack Width Calculation Methods for Steel-GFRP Strips-UHPC Composite Deck
Three GFRP-UHPC composite deck panels and two steel-GFRP strips-UHPC composite beams were designed for four-point and three-point bending tests,respectively,to investigate the crack propagation and distribution in the steel-CFRP strips-UHPC composite deck.The study focuses include the failure modes and mechanism of the composite panels and beams,the influence of reinforcement ratio and steel fiber content on the cracking performance of the composite panels and beams,the applicability of the maximum crack width calculation methods suggested by the current codes for the composite deck,as well as the maximum crack width calculation equations suitable for the steel-GFRP strips-UHPC composite deck,following the unified theory of slip and considering the influence of the concrete cover thickness on the average crack spacing and the contribution to the tensile strength of concrete.It is demonstrated that when the steel-GFRP strips-UHPC composite beams failed,obvious flexural deformation was observed in the lower flanges of the steel girders,cracks were mainly in the midspan region of the upper surfaces of the composite beams,and the GFRP layer and UHPC layer of the GFRP-UHPC composite panel were disengaged at the ends,where the cracks were mainly in pure-bending moment zone.Improving the tensile reinforcement ratio led to the enhancement of the ultimate bending capacity,suppression of the propagation of the cracks in the surfaces of UHPC layer,reduction of crack width and average crack spacing,while the increase of steel fiber content exerted minor influence on the ultimate bending capacity and flexural stiffness.The maximum crack widths calculated using the equations given by current codes were smaller.The maximum crack widths calculated by the proposed equations in this paper agree well with the test results,justifying their applicability.
万方数据
维普
