Evaluation of Longitudinal Force on a Railway Bridge Based on Strain Measurements


V. Srinivas, CSIR-Structural Engineering Research Centre, CSIR Campus, TTTI(Post), Taramani, Chennai 600 113, India
Email: srinivas@sercm.org


Evaluation of longitudinal force is very important for the performance evaluation of older bridges and for the design of new bridges. There is a growing demand to increase freight haulage in railway networks, in particular, on the iron ore routes of various zones of Indian railways. This proposed alteration may subject the bridges to higher tractive effort/braking forces together with higher axle loads. It is thus obvious that there is a need to check the performance of the concerned bridges under this proposed increased loading. Hence, as part of evaluating the bridges for higher axle loads, experimental investigations have been carried out on a typical steel plate girder railway bridge. This paper gives the summary of experimental investigations, test setups, and results obtained for the evaluation of longitudinal force. The longitudinal force evaluated based on the experiments for the increased axle loads is found to be within the design limits specified. The special fixtures developed for direct measurement of the longitudinal force are found to give the reliable results compared to the strain gage measurements on the girder. The results show that only part of the rail force is transmitted to the girder.