青岛市墨水河大桥索梁锚固区受力分析

Stress Analysis of Cable Girder Anchorage Zone of Moshui River Bridge in Qingdao City

青岛市墨水河大桥主桥为2×90 m单塔中央双索面斜拉桥。主梁采用分体式箱形截面钢主梁,斜拉索与钢箱梁内边腹板之间通过钢锚箱连接,索梁锚固区的传力途径和受力情况较复杂。利用有限元软件midas FEA对索力最大的索梁锚固区及附近梁段进行板壳单元有限元分析,对索力最大的钢锚箱及局部腹板进行实体单元有限元分析。结果表明,对于中央索面分体式钢箱梁斜拉桥,顶底板等效应力峰值出现在联系横梁跨中;联系横梁腹板所对应的箱室内横隔板比拉索横隔板的应力水平高;通过设置腹板局部补强板,锚固区腹板变形和应力均可满足受力要求;钢锚箱锚固于内边腹板外侧,斜拉索张拉施工和后期养护均较方便。

The main bridge of Moshui River Bridge in Qingdao City is a single tower central double cable plane cable-stayed bridge with span of 2×90 m.The main girder adopts the split box section steel main girder,and the stay cable is connected with the inner web of the steel box girder through the steel anchor box.The force transmission path and stress situation of the cable girder anchorage zone are complex.The finite element software MIDAS FEA is used to analyze the cable girder anchorage zone and adjacent beam section with the largest cable force,and the solid element finite element analysis is used to analyze the steel anchor box and local web with the largest cable force.The calculation results show that for the central cable plane split steel box girder cable-stayed bridge,the peak value of equivalent stress of the top and bottom plate appears in the middle span of the connecting beam,and the stress level of the diaphragm in the box corresponding to the web of the connecting beam is higher than that of the cable diaphragm.The deformation and stress of the web in the anchorage zone can meet the stress requirements by setting local reinforcing plate of web.Moreover,the steel anchor box is anchored on the outside of the inner web,which is convenient for stretching construction of stayed cable and later maintenance.