北江大桥为多跨连续梁桥，由于佛开高速扩建，该桥引桥采用整体同步顶升施工，需顶升0．150～1．491 m。为分析该桥在顶升施工中的梁体受力，为施工提供指导，采用ANSYS软件建立该桥15～22号墩连续梁模型，对同步顶升力、落梁调整到位后梁体的受力进行计算分析，并研究纵、横向误差对梁底应力和支座反力的影响。结果表明：在同步顶升过程中，理论顶升力与实测值接近；落梁后梁体应力变化的理论值与实测值接近，梁体仍处于受压状态；1 cm的纵向顶升误差不会使梁体出现拉应力，也不会使支座反力出现较大变化；1 cm的横向顶升误差使梁体出现拉应力，使支座反力出现较大变化。因此须严格控制顶升误差，建议纵向顶升误差不超过10mm，横向不超过5mm。%The Beijiang River Bridge is a multi‐span continuous girder bridge .The approach bridge of the bridge needed to be constructed by the integral and synchronous jacking‐up owing to the expansion of Foshan‐Kaiping Expressway and was to be jacked up 0 .150~1 .491 m .To ana‐lyze the force conditions of the continuous girder of the approach bridge in the process of the jack‐ing‐up construction and to provide guidance for the construction ,the software ANSYS was used to establish the model for the girder of the bridge atop Piers No .15~ No .22 ,the synchronous jacking‐up forces and force conditions of the girder after the girder was lowered down and adjus‐ted were calculated and analyzed and the influences of the longitudinal and transverse jacking‐up errors on the girder bottom stress and bearing reaction forces were studied .The results of the study show that in the integral and synchronous jacking‐up construction , the theoretical and measured jacking‐up forces are close .The theoretical and measured values of the stress changes of the girder after the girder is lowered down are close and the girder remains the state of com‐pression .The longitudinal jacking‐up error of 1 cm will neither cause the girder to have tensile stress ,nor cause the bearing reaction forces to significantly change .The transverse jacking‐up error of 1 cm will cause the girder to have tensile stress and cause the bearing reaction forces to significantly change .In such case ,the jacking‐up errors should be strictly controlled and it is proposed that the longitudinal jacking‐up error should not be greater than 10 mm while the trans‐verse jacking‐up error not be greater than 5 mm .
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