超高性能混凝土板冲切与弯曲性能研究

RESEARCH ON PUNCHING SHEAR AND BENDING BEHAVIOR OF ULTRA-HIGH PERFORMANCE CONCRETE SLABS

超高性能混凝土(Ultra-high performance concrete,简称UHPC)桥面板具有良好的应用前景。桥面板在车轮荷载作用下存在冲切和弯曲问题,以此为背景设计了系列UHPC板件试验,主要研究板的厚度、保护层厚度、配筋率及加载区域面积等参数对试验板抗冲切及抗弯性能的影响,分析了不同试件的破坏模式、挠度、应变分布以及整体延性等,并提出UHPC板抗冲切极限承载力计算方法。试验结果表明:UHPC板的破坏模式包括冲切破坏、弯曲破坏和二者混合的冲弯破坏;相比于C50混凝土板,UHPC板的刚度、抗冲切承载力及位移延性有显著提高;随着板厚增大、保护层厚度减小、加载区域增大,UHPC板的抗冲切承载力提高。经过试验数据验证,抗冲切及抗弯承载力的计算值与试验值吻合良好。

Ultra-high performance concrete(UHPC) bridge deck has good prospects for engineering application.In order to study the punching shear and bending behavior of bridge deck under wheel loading, a series of UHPC slab tests were designed. The effects of slab thickness, cover thickness, reinforcement ratio and loading area on the punching shear and bending behavior of the slabs were studied. The failure modes, the deflection, the strain distribution and the ductility of different specimens were analyzed. And the calculation methods of punching shear capacities of UHPC slabs were proposed. The test results show that the failure mode includes punching shear, flexure and mixed punching-flexure mode. The stiffness, the punching capacity, the ductility and the energy absorption capacity of the UHPC slabs are much higher, compared with the C50 concrete slab. And the punching shear capacity of UHPC slabs increases with the increase of slab thickness, with the decrease of cover thickness and with the increase of loading area. Verified by the test data, the calculated values of punching shear and bending bearing capacity are in a good agreement with the test values.