Measurements and simulation of the dynamic responses of a bridge–embankment transition zone below a heavy haul railway line

Chinese Railways is seeking to increase the capacity of many of its heavy haul railway lines by increasing their utilization and at the same time increasing axle loads from 250 to 300 kN. These projected increases in railway traffic may result in accelerated deterioration of the railway network. A vulnerable part of the network, are bridge–embankment transition zones which frequently experience high degradation rates. To investigate the possible implications of the forecasted increases in railway traffic on these structure, a study was carried out which consisted of instrumenting a transition zone to measure accelerations under existing loads and building a three-dimensional finite element dynamic model of the bridge–embankment transition to predict the effects of the anticipated future traffic. The results of the study indicated that commonly used measures of stability, safety and substructure damage would remain within specified limits, despite the projected increases in axle load. However, excessive wear of the wheel and or rail may occur.