Heavy-cargo passage on arch bridges by matching attached loads

It is common practice to transport heavy equipment via highway bridges. However, their strength may be insufficient in some situations and at present there are limited solutions applicable to long-span arch bridges. A matching load technique was thus developed by which vehicles with heavy cargo can pass over bridges by carefully placing calculated supplementary loads on the structures instead of applying strengthening. In this work, the relation between the strength of an arch section and the deviation of the thrust line from the neutral axis was analysed. It was found that arches have great reserves of strength if the deviation is minimised. Then, the crucial role that the eccentricity of the thrust on a section plays in current strength calculation algorithms was investigated. As a consequence, a criterion employed to examine qualitatively whether the section has adequate strength was established. Based on these analyses, the matching load technique was developed. The technique was validated on a 130 m long single-span arch bridge and was shown to provide a passage scheme to allow the safe transportation of a 400 t load.