Assessing ballast cleaning as a rehabilitation method for railway masonry arch bridges by dynamic load tests

Abstract

Dynamic load testing has become a common practice for condition assessment of masonry arch bridges and lays the foundation for their rehabilitation procedures; however, additional dynamic testing after rehabilitation is rare. Carrying out dynamic load tests before and after rehabilitation programs produces valuable results with regard to the structural changes of the bridge. This paper tries to assess the effects of ballast cleaning on the performance of railway masonry arch bridges by conducting dynamic load tests before and after the rehabilitation procedure. To do so, a 70-year-old masonry arch bridge is instrumented with deflection meters and accelerometers. Dynamic load tests are carried out before and after ballast cleaning and results are compared. According to the test results, vertical deflections of different spots on the bridge remain the same, with a deviation of less than 5%. On the other hand, vibrations on the structure are reduced significantly. On average, vibration levels are reduced by 35% in different spots of the structure.