拱桥加固施工中的配重设计方法

摘要

In the process of reinforcing construction of long-span masonry arch bridge, usually in some steps main arch of bridge had insufficient bearing capacity due to badly-distributed inner forces,etc. To solve this problem, the authors presented the method of arranging temporary supplement loads on proper position of bridge to balance the structure. Firstly, based on the detailed analyzing relation between ultimate bearing capacity of masonry arch bridge and eccentricity of resultant forces on an arch section, eccentricity was chosen as critical parameter and used to determine whether the section had sufficient capacity without complete calculation. Then, design method of arranging balance weight during reinforcing construction of masonry arch bridge was proposed, and this method was to limit the divergence between eccentricity of resultant forces on section in certain construction step and its boundary [ e0 ] by properly distributing supplement load . In order to validate the above method, a 2-span concrete arch bridge with 100 m span length was introduced and its plans of balance weight for 3 construction steps were discussed.%为了解决大跨径圬工拱桥加固施工阶段由于内力分布不佳等导致结构强度不足的问题，提出通过在结构上适宜位置布置施工临时配重的解决方法。分析了圬工拱的极限承载力与合力偏心距e之间的关系，研究结果表明：利用偏心距e与其限值[ e0]之间的相对关系可快速、定性判断圬工拱截面承载力是否足够。通过合理调整配重荷载量值与布置位置以控制加固施工过程中截面e不超过容许值[ e0]或预设值，提出了大跨径圬工拱桥加固施工配重方案设计方法。以一座2×100 m混凝土箱板拱桥加固施工中3个阶段的配重方案设计为例，检验了方法的可行性与有效性。