公路工程

为研究可处治大跨度连续刚构桥跨中下挠病害的二次加固方案，基于安乐塘大桥首次提出增设钢管混凝土格构式中墩的加固方法，同时将增设矮塔斜拉和增设中腹板作为加固比选方案；随后对各加固方案的结构响应和经济性进行对比分析；最后介绍了增设格构式中墩加固的主要施工工艺以及加固后评价。结果表明：受力方面，增设格构式中墩的加固效果优于其他两种方案，能有效降低梁体和桥墩的内力响应；下挠处治方面，相较于加固前的下挠值，增设矮塔斜拉、增设中腹板、增设格构式中墩加固后分别减小41.95%、42.2%和56.1%;经济性方面，增设矮塔斜拉和增设中腹板造价较低，但对交通影响较大，而增设格构式中墩加固对社会经济的影响最小；桥梁在采用增设钢管混凝土格构式中墩加固后，其受力、变形、竖向刚度及整体工作性能均得到明显的改善。

For the study of secondary strengthening schemes for treating mid-span deflection diseases in long-span continuous rigid bridges, for the first time, a reinforcement method was proposed for the Anletang Bridge by adding concrete-filled steel tube lattice middle piers. At the same time, the addition of low tower diagonal braces and middle web plates were selected as reinforcement options.Subsequently, a comparative analysis of structural response and economy was conducted for each reinforcement scheme. Finally, the main construction techniques and post-strengthening evaluation of the added lattice middle piers were introduced. the results indicate that, in terms of structural behavior, the reinforcement effect of the added lattice middle piers is superior to the other two schemes, effectively reducing the internal forces in the beams and bridge piers. Regarding the treatment of excessive deflection, compared to the deflection values before reinforcement, the addition of short tower cables, mid-span diaphragms, and lattice middle piers reduced the deflection by 41.95%, 42.2%, and 56.1% respectively. In terms of economy, the addition of short tower cables and mid-span diaphragms have lower costs but have a greater impact on traffic, while the reinforcement with lattice middle piers has the least impact on the socio-economic aspects. After adopting the reinforcement with concuete-filled steel tube lattice middle piers, the bridge exhibited significant improvements in load-carrying capacity, deformation, vertical stiffness, and overall performance.