基于钢管连接件的钢-UHPC组合桥面板抗剪性能研究

针对公路钢桥桥面结构因自身刚度相对较弱和抗拉拔力不足,出现铺装层病害和钢桥面板疲劳开裂等现象,提出一种基于钢管连接件的钢-UHPC组合桥面板结构,为研究该新型连接件组合桥面板的抗剪性能,开展了推出试验,并结合试验验证后的非线性数值模型得出了试件的工作机理。运用非线性数值模型分析了抗剪连接件厚度、连接件屈服强度、UHPC抗压强度对抗剪承载力及抗剪刚度之影响。研究表明:钢管连接件推出试验破坏形态为下缘焊缝附近的钢管壁沿焊缝方向被剪切断裂,其下部UHPC被压碎;参数分析得出其他参数不变的情况下,抗剪性能随连接件钢管壁厚和钢材强度均呈线性增长;不同的连接件壁厚对应合理的UHPC轴心抗压强度取值,钢管外径为40 mm的情况下,壁厚从3、4、5、6 mm变化取值,对应的UHPC抗压强度合理值分别为100、120、140、160 MPa。

Shear Performance Research on Steel Tube Connector of Steel and UHPC Composite Deck

For relatively low stiffness and insufficient lifting resistance,steel decks in highway bridges are vulnerable to pavement damage and fatigue cracks.A new-type steel-UHPC composite deck with steel tube connectors was investigated through push-out tests.The finite element model(FEM),verified by tests,was used to master work mechanism and influence of tube wall thickness,connector strength,and concrete strength on shear behavior.Failure modes of push-out specimens were shear fracture of tube walls near lower seams in the direction of welding,and UHPC under connector was crushed.Parametrical results showed that shear performance of the composite deck was enhanced linearly with increments of tube thickness or steel strength.For the tube connector with 40-mm outer diameter,as wall thickness was changed in the range of 3,4,5 and 6 mm,recommended values for concrete axial compressive strength were 100,120,140 and 160 MPa,respectively.