Field Testing of Old Narrow-Gauge Railway Steel Truss Bridge

Investigation results of a historic narrow-gage railway steel truss bridge built in 1936, still in use, is presented. During the World War II the bridge was exploded and has been restored later after the war (1946). The original design documentation was lost. The aim of this study is to investigate the structural condition and the behaviour of the riveted steel truss bridge with the aid of full-scale static and dynamic testing. The field load tests have been conducted to develop an analytical model, to be used for assessment of bridge capacity. Static and dynamic tests of the bridge using two original locomotives were performed. Supplementary dynamic tests using impulse excitation were also carried out. The responses (stresses, static and dynamic displacements, accelerations, mode shapes, corresponding resonant frequencies and modal damping values) of bridge superstructure were determined. Research has shown that the bridge exhibit sufficient reserve of capacity for safe operation.