The bridge on Km 475+650 of Iranian railway network is a stone masonry arch bridge which has been in service for about 75 years. The bridge consists of four spans of 25m and four spans of 8m, totalling a length of 176 meters. The bridge accomodates a single track with an allowable axle load and speed of 20 tons and 60 Km/h. Track's superstructure consists of U33 rails, steel sleepers, and rigid fasteners. 

Summary of results:

The bridge has been controlled in serviceability and ultimate limit states. Three distinct loading patterns are considered throughout the analyses. It is shown that the bridge is not capable of handling an increased axle load in SLS. Moreover, ULS analyses show that bridge's load factor is 1.57. Seismic assessment of the bridge is also carried out and it is shown that the bridge requires retrofitting for withstanding earthquake forces.