超高性能混凝土带肋桥面板抗弯及抗冲切性能试验

Experimental study on flexural and punching shear performance of ribbed UHPC bridge deck panels

摘要:

超高性能混凝土（ultra-high performance concrete,UHPC）因其优异的力学性能和耐久性,近年来在桥梁工程中得到了广泛应用。为了在保持UHPC高性能的同时降低成本,以1.2%体积掺量的平直形镀铜微细钢纤维配置UHPC,并通过不同配筋条件（普通钢筋和高强钢筋）下UHPC带肋桥面板的抗弯性能与抗冲切性能试验,研究其力学性能和破坏特征。结果表明:不同配筋条件下UHPC带肋桥面板均为受弯破坏,表现出良好的延性,采用高强钢筋显著提高了极限承载力,充分发挥了其材料性能；在抗冲切性能方面,不同配筋条件下UHPC带肋桥面均呈现冲切破坏模式,具有较大延性；相同配筋率下,高强钢筋可提高受冲切承载力约25%,但配筋率增加对承载力的影响有限。研究结果证明,使用较低体积掺量的钢纤维和高强钢筋,可在降低成本的同时充分发挥UHPC和高强钢筋的优越性能,提高结构耐久性和经济性。

Abstract:

Ultra-high performance concrete (UHPC) has been widely used in bridge engineering in recent years due to its superior mechanical properties and durability. To reduce costs while maintaining the high performance of UHPC, this paper investigates the mechanical properties and failure characteristics of ribbed UHPC bridge decks reinforced with 1.2% volume fraction of straight copper-plated micro steel fibers, under different reinforcement conditions (ordinary steel bars and high-strength steel bars), through bending and punching shear performance tests. The results indicate that UHPC ribbed bridge decks exhibited good ductility and flexural failure modes under different reinforcement conditions. The use of high-strength rebar significantly improved the ultimate bearing capacity, fully utilizing the material properties of the high-strength reinforcement. In terms of punching shear performance, the UHPC ribbed bridge decks showed a punching-flexural failure mode with substantial ductility. High-strength rebar increased the punching shear capacity by approximately 25% at the same reinforcement ratio, but further increases in reinforcement ratio had limited impact on bearing capacity. The findings demonstrate that using lower volume fractions of steel fibers and high-strength rebar can reduce costs while maximizing the superior properties of UHPC and high-strength steel bars, enhancing both the durability and economic efficiency of structures.