大跨径预应力混凝土变截面连续箱梁桥加固分析

Reinforcement analysis of large span PC variable cross-section continuous box girder bridge

针对某大跨径预应力混凝土变截面连续箱梁桥病害,提出了处理措施及加固方案,建立了有限元模型,对可选加固方案进行了结构分析,最后对所选定加固方案进行了验算分析。结果表明:当梁底存有大量混凝土空鼓、崩裂病害时,不宜通过张拉原备用束方式来增强压应力储备,采用的增设体外预应力、改造桥面铺装、粘贴钢板及粘贴碳纤维布等加固方案效果良好。

In view of the specific diseases of a large span PC variable cross-section continuous box girder bridge,a set of treatment measures and reinforcement schemes are proposed,a finite element model is established,and a series of structural analyses of optional reinforcement schemes are carried out. Finally,a calculation analysis of the selected reinforcement scheme is conducted. The results show that,when there are a large number of diseases such as concrete cavities and breakup at the bottom of the beam,it is not suitable to strengthen the compressive stress reserve by tensioning the original spare pre-stressed tendon. The reinforcement schemes such as adding external prestressed tendons,transforming deck pavement,pasting steel plates and carbon fiber cloth work well.