Deminishing classic steel arch bridges' horizontal bracings

In the 19th and 20th century steel arch bridges were constructed from slender profile members, mostly assembled by riveting. Many of these structures are now considered as heritage. Most compressed members, in particular arches are supplemented with complex horizontal bracings. The latter were intended to increase lateral stiffness and to prevent any stability issue of compressed members. In general these bracings are abundant and even exaggerated. Corrosion is sometimes heavy in bracings, since these are complicated members and are exposed. The question then arises whether some parts of the bracings are really necessary. Replacing bracings may show too much risk and removal of the deteriorated parts may not harm the efficiency of the arch. In this study the Stambolov bridge in Bulgaria and the ‘Pont de Fétinne’ in Liège (B) across river Ourthe, are considered for reducing the bracing systems. For Stambolov bridge a considerable number of bracing elements can be removed without further consequence. In the case of Fétinne bridge 2 scenario’s for eliminating bracing members are possible. Both examples demonstrate the possibility to reduce the complexity of the horizontal bracings.