预应力连续箱梁特殊检查与施工监控研究

Research on special inspection and construction monitoring of prestressed continuous box girders

依托某预应力混凝土连续箱梁,以桥梁特殊检查和加固施工过程监控为研究对象。对桥梁外观进行详细检查。在此基础上制定体外预应力加固混凝土连续箱梁加固方案,采用有限单元法进行理论计算,对施工过程中的主梁线形、应力进行控制,保证桥梁能够安全顺利完成施工并达到理想线形,并对加固后桥梁线形及动刚度进行检测。特殊检查结果表明:桥梁因预应力损失、截面尺寸偏小等使得桥梁产生横向裂缝、结构动刚度减小,并最终评为5类桥;监控结果表明:采用体外预应力技术加固,主梁的挠度与混凝土应力在安全可控范围内,桥梁线形有所改善、动刚度有所提升,达到了加固设计要求。

Relying on a pre-stressed concrete continuous box girder,the special inspection of the bridge and the monitoring of the reinforcement construction process are studied.The bridge results are inspected in detail.On this basis,an in vitro prestressed reinforced concrete continuous box girder reinforcement program is formulated,and the finite unit method is used for theoretical calculations to control the main girder line shape and stress during the construction process,so as to ensure that the bridge can complete the construction safely and successfully and reach the ideal line shape.The linear shape and dynamic stiffness of the reinforced bridge were also examined.The special inspection results show that the bridge has transverse cracks and reduced structural dynamic stiffness due to prestressing loss and small cross-section size,and finally rated as a category 5 bridge;the monitoring results show that the deflection of the main girder and the concrete stress are within the safe and controllable range after strengthening by the extracorporeal prestressing technique,and that the bridge line shape has been improved and dynamic stiffness has been prompted to meet the design requirements of the reinforcement.