新旧混凝土连续箱梁拼接桥梁端横向位移分析

Analysis of Lateral Deviation of the Widened Concrete Continuous Box Girder Bridge

某高速公路上2座混凝土连续箱梁桥在与新桥拼接后出现了端支点处梁体向外侧横向偏位的现象。为对此现象产生的原因进行分析,现场实测了其梁端横向位移值,同时建立了梁格有限元模型以进行横桥向位移的计算。比较结果表明2座桥的有限元模型计算结果与现场实测值均比较接近,梁格模型计算值能反映梁体实际横向偏位情况。理论分析表明新旧桥混凝土收缩徐变差是产生该现象的主要原因。最后提出针对此类桥的维修和设计,应结合有限元模型计算所得横桥向位移值,对支座、挡块及伸缩缝采取一定的构造措施,以适应运营过程中出现的梁端横向偏位效应。

Two concrete continuous box girder bridges＇ ends moved laterally after widening with the new bridges. To investigate the cause of this phenomenon,the values of the lateral displacement were measured on the field. The grillage model was also established to calculate the bridges ＇ transverse displacement. The comparison result showed that both bridges＇ measured value and calculated value were close which indicated that the actual lateral deflection could be calculated accurately by the grillage model. Theoretical analysis and numerical results showed that the difference between the new and old bridges＇ creep and shrinkage property due to the concrete age was the main cause for this phenomenon.At last,it is recommended that,during the design and repair of this kind of bridge,in order to adapt to the lateral move of the girder,special considerations should be given to the design of bearings,blocks and expansion joints based on the lateral displacement of the finite element model.