为了解决圬工拱桥特别是大跨圬工拱桥临时通行重型、特重型车辆的问题，提出了不须加固结构仅需动态、合理地布置附加荷载的通行方法———平衡加载法。首先，分析了圬工拱结构的承载力与压力线和拱轴线之间偏离的关系，论证了在拱上合理布置荷载以使两线偏离尽量缩小前提下拱圈能够承担质量远超其设计荷载的重载的观点。其次，在深入分析偏心受压圬工构件的极限承载力计算方法的基础上，以截面合力偏心距e作为快速、定性判断承载力是否足够的关键参数。以偏心距e作为控制参数，提出在不经加固的圬工拱桥上动态地设计附加荷载的运动路径以配合重载通行的方法和流程、重要技术手段。以总质量为400 t的重载临时通过一座净跨径130 m的混凝土箱板拱桥为例，展示、检验了该方法。理论研究与实践结果表明：平衡加载法能够在不进行结构加固条件下有效解决圬工拱桥临时通行重载的问题。%In order to solve the problem of how to temporarily carry heavy vehicle whose load magnitude is far more than that of its design load, for long-span masonry arch bridge, a balance-loading method, by which heavy cargoes can be bore not by structural retrofitting but dynamically moving supplement vehicle, was presented in this paper. Firstly, the relation between ultimate bearing capacity of masonry arch and deviation of thrust line from neutral axis of its section was analyzed. It was concluded that if loads were properly distributed, the arch structure could afford to bear far more heavy loads. Secondly, based on detailed analysis of calculation method of ultimate bearing capacity for masonry elements eccentrically loaded, the eccentricity of resultant forces on section was chosen as a critical parameter to qualitatively determine if the section had sufficient capacity without detailed calculation. With the eccentricity, the method of temporarily carrying heavy vehicle without structural strengthening was proposed, and the corresponding procedure and key technical measures were also discussed. Finally, for a concrete arch bridge with box section and span length of 130 m a detailed plan of carrying a vehicle of total 400 tons weight was presented. Both theoretical study and practice show that the proposed method is feasible.
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