Abstract: The bridges in service have some diseases with different degrees, which will cause some damages on the bridge structure, so they are strengthened in order to guarantee the safety. It is very effective to apply the externally prestressing reinforcement technology in improving the engineering performance of reinforced concrete bridges. Firstly, the bending analysis and nonlinear simulation of PC box girder with externally prestressing reinforcement were carried out; secondly, the lane load factor β was introduced and its value was checked, which proved that the externally prestressing reinforcement met the load design requirements. Then, a PC box girder with externally prestressing reinforcement was designed and calculated. The working state of bridge under nonlinear condition was obtained through the contrast of bridge reinforcement effect. The calculation results show that the bearing capacity, deflection and crack reinforcement of the bridge are obviously improved by the measure of external prestressing reinforcement.

Key words: bridge engineering, externally prestressing, PC box girder, nonlinearity analysis, bridge reinforcement

摘要： 由于在役桥梁存在不同程度的病害，桥梁结构会产生一定的损伤，所以为保证安全性需要对这些存在病害的桥梁采取加固措施。体外预应力加固技术对提升钢筋混凝土桥梁的工程性能具有显著优势，从PC箱梁体外预应力加固的抗弯分析和非线性模拟展开研究，引入车道荷载系数β，通过验证车道荷载系数的取值，证明采用体外预应力加固满足设计荷载要求。之后对某PC箱梁桥的体外预应力加固工程进行了设计计算，对桥梁的加固效果进行对比分析，得出桥梁非线性条件下的工作状态。计算结果表明：通过体外预应力加固措施，桥梁的承载能力、挠度和裂缝加固效果均得到了明显提升。

关键词: 桥梁工程, 体外预应力, PC箱梁, 非线性分析, 桥梁加固