山区PC箱梁桥墩柱抗震性能加固研究

Research on Seismic Performance and Reinforcement of PC Box Girder Bridge Pier Column in Mountainous Area

为提升山区梁桥墩柱抗震性能,文章依托一座双柱式高墩预应力混凝土连续箱梁桥(PC箱梁桥),利用Midas Civil有限元软件建立结构弹塑性分析模型和Pushover推倒分析模型,分析同联内不同墩高差与不同墩柱配筋率对结构抗震性能的影响,并提出相应的措施及建议。研究结果表明:同一联内墩高相差过大,将极大增加同一联内各墩柱地震动响应分布的不均匀性,矮墩将承受更大的剪力,可能发生剪切脆性破坏,不符合桥梁抗震延性设计要求;双柱式桥墩塑性铰区易出现在墩顶、墩底和系梁处,适当提高墩柱塑性铰区配筋率可以提升墩柱的抗力和延性。该工程墩柱配筋率取1.29%,墩高差取10m时结构抗震效果良好。

In order to improve the seismic performance of bridge pier column in mountainous area,relying on a prestressed concrete continuous box girder bridge with double-column high pier(PC box girder bridge),the structural elastic-plastic analysis model and Pushover analysis model are established by using the Midas Civil finite element software,the impact of different pier height differences and reinforcement ratios on the seismic performance of the structure is analyzed,and the corresponding measures and suggestions are put forward.The research results show that:if the height difference of the same pier is too large,it will greatly increase the non-uniformity of the seismic response distribution of each pier column in the same pier.Short piers will bear greater shear force and may experience the shear brittle failure,which does not meet the seismic ductility design requirements of the bridge;the plastic hinge zone of the double-column bridge pier is prone to occur at the top,bottom,and tie beam.Properly increasing the reinforcement ratio of the plastic hinge zone of the pier column can enhance the resistance and ductility.The seismic performance of the structure is good when the reinforcement ratio of the pier is 1.29%and the height difference of the pier is 10m.