Abstract: With the prosperity and development of China's economy, the rapid growth of traffic flow poses a severe challenge to the structural safety of old bridges. In this paper, taking a continuous box girder bridge in the south approach of a Yangtze River Bridge as the object of study, aiming at a variety of crack diseases caused by the lack of effective maintenance due to long-term operation, the cause of the disease was determined by field detection and finite element analysis, such as the loss of steel bundle prestress and the degradation of structural performance. The applicability of different reinforcement technologies was comprehensively analyzed, and a reinforcement scheme for arranging external prestressed steel bundles inside the box girder was proposed. This scheme not only significantly improves the stress state of the bridge span structure, increases its bearing capacity by about 17.26%, but also greatly reduces the tensile stress level of the bridge span by up to 50.80%, effectively eliminating the structural safety hazards and ensuring the safe operation of the bridge.

Key words: bridge reinforcement, continuous box girder bridge, external prestressed steel bundle, finite element analysis

摘要： 随着我国经济发展,交通流量的急剧增长对老旧桥梁的结构安全构成了严峻挑战。文中以某长江大桥南引桥——一座连续箱梁桥为研究对象,针对其因长期运营缺乏有效维护而产生的多种裂缝病害,通过现场检测与有限元分析方法,确定了病害成因为钢束预应力损失导致结构性能退化。综合分析不同加固技术的适用性,提出了在箱梁内部布置体外预应力钢束的加固方案。该方案不仅显著提升了桥跨结构的应力状态,使其承载能力增强约17.26%,更大幅降低了桥跨的拉应力水平,降幅高达50.80%,有效消除了结构安全隐患,确保了桥梁的安全运营。

关键词: 桥梁加固, 连续箱梁桥, 体外预应力钢束, 有限元分析