OPERATING STATE OF SPAN CONSTRUCTIONS OF EXISTINGMETALLIC BRIDGES ON AUTOMOTIVE ROADS IN THE WESTERN AREAS OF UKRAINE

By using the examples of large – scale inspections of metallic bridges the defects and damaqes of elements, the degradation of structural materials are shown. The examples of structure imperfection, tipical defects, operation drawbacks are illustrated. Construction defects are the most numerous and can significantly affect the operational reliability and durability of the surveyed bridges. Basically it is: departure from the project, use of substandard materials and violation of production technology; their share accounts for 55% of the surveyed bridges. It is shown that the degree of influence of defects on the bearing capacity and durability spans depending on their location, character, width and size of disclosure under temporary stress. The main danger of all detected defects is that they are not controlled by the calculation. It is established that a considerable part of surveyed structures works under load in the calculated mode. However, in some runways, there may be more dangerous situations that threaten the lowering of the load capacity of runways. The part of bridges in “4” and “5” operating conditions increases year by year, which indicates a decrease in the reliability of bridge structures. There is an accumulation of volumes of repair works that have not been performed in previous years. The task is to develop criteria for assessing the effectiveness of bridge repairs with limited residual resources, as well as developing rational reinforcement schemes for structures located on high load highway traffic routes.