钢-混凝土混合结构在大跨度连续刚构桥中的应用

重庆石板坡公路长江大桥采用填充混凝土后板式钢—混凝土接头。在轴力、弯矩和剪力的作用下,钢—混凝土接头处将产生轴向压应力、拉应力和剪应力。压应力由承压板及PBL剪力键共同传递,拉应力、剪应力主要由PBL剪力键传递。计算得到钢—混凝土接头的最不利荷载组合内力。在钢—混凝土接头附近截取18m长的1个梁段,将混凝土与贯穿钢筋进行耦合、贯穿钢筋与PBL板进行耦合,采用实体单元、板单元和梁单元,建立钢—混凝土接头有限元模型,利用有限元软件ANSYS进行仿真分析,得到钢—混凝土接头各部分的应力分布。结果表明:结构各构件在设计荷载下并未出现超出材料强度的应力峰值;剪力主要靠腹板上的PBL剪力键传递;有效的预应力体系是钢—混凝土接头可靠性的根本保证。

Using Steel-Concrete Hybrid Structure in Long-Span Continuous Rigid Frame Bridge

Steel-concrete joint in backboard form is used in Yangtze River highway bridge at Shibanpo in Chongqing.Under axial force,moment and shear force steel-concrete joint subjected to compressive stress,tensile stress and shear stress.Compressive stress is transferred by carrying plate and PBL(Perfo-Bond Leisten) shear connectors.Tensile stress and shear stress are transferred by PBL shear connectors.The internal forces of steel-concrete joint were computed as a result of the most unfavorable combination of loads.With displacement coupling between concrete and steel bar and between PBL shear connectors and steel bar,finite element model of steel-concrete joint which is 18 m in length was founded by using solid element,plate element and beam element.By using ANSYS,elastic-plastic analysis of steel-concrete joint was performed and stress distributing condition of steel-concrete joint was obtained. FEM results show that PBL shear connectors carry main shear forces between steel girder and concrete girder and structural reliability of steel-concrete joint depends on the effective prestressed system in steel-concrete joint.