Structure evaluation of medium span steel bridges

In last few years’ a significant number of highway and railroad structures in Croatia were built and repaired. Among them are bridge ˝Gacka˝ (55m + 90m + 55m) and bridge ˝Jasenovac˝ (60.55m + 120m + 55,35m). Two bridges were constructed from steel and they are continuous static system over three spans. Superstructure consists of the orthotropic steel slab with box girders. Like all bridges in Croatia, these two were tested according to the Croatian regulations and norms before they had been opened for traffic. Static and dynamic load testing involved the process of loading and observation of the related reactions of an existing structure for the purpose of assessment load bearing capacity, safety and serviceability. Paper describes testing procedure (static and dynamic), measurements methods, and analytical models of structures. Each bridge has been modelled with different approach. Some results of comparing measured and calculated data of both bridges are also shown. This study were conducted to find out witch model matched better the actual situation of the tested structures.