佛开高速公路北江大桥改造前后力学性能分析

佛开高速公路北江大桥采用主桥拆除重建、引桥顶升加固的改造方案。由于引桥连续工字梁存在结构性病害，顶升对梁体的影响需进行评估。同时，顶升误差将导致梁体产生次应力，可能导致梁体出现新的损伤，此外，顶升过程中连续工字梁的结构体系多次发生转换，多次体系转换后梁体的受力性能是否满足要求需进行分析。对北江大桥引桥连续工字梁的典型联跨改造前后的受力性能进行分析，得到其受力性能的变化规律，为桥梁改造施工提供理论依据。

Research on Mechanical Properties of Beijiang Bridge before and after Improvement of Fokai Expressway

Demolition and reconstruction have been implemented for the main bridge of Beijiang Bridge, jacking and reinforcing method have been designed for the approach bridges. Due to existing structural disease of the continuous I-beams, the effect of lifting to the beams has to be evaluated. At the same time, lifting error may lead to secondary stress of the beams, which may cause new damages; in addition, as many conversions of the continuous beams have occurred during the jacking process, it has to be analyzed that if the stress properties of the beams could meet the requirements after several times of system conversions. By studying on stress properties before and after the reinforcing of the typical combination of continuous I-beams of Beijiang Bridge, the change law of the stress properties has been obtained, which will provide theoretical basis for the bridge construction.