Characterizing the Dynamic Water Pressure in a Concrete Tie Rail Seat
Concrete railroad ties withstand higher loads and traffic volumes than railroad ties produced from other materials. The service life of a concrete tie can be shorter than expected due to durability problems. Rail seat deterioration (RSD) is the main cause of durability problems in concrete ties. The objective of this project is to provide an idea of what behaviors to expect from water pressures in the interface of a concrete rail seat and a tie pad. This was done by simulating the mechanisms present in the interface between the rail seat and a tie pad. The experiment featured cyclic loading acting on top of a steel plate. The cyclic loading simulated the frequent loadings of the axles on a rail seat. The steel plate features an orifice which holds a pressure transducer that provided us with pressure readings for the different settings recreated in the experiment. Our results demonstrated a difference in pressure readings when changing tie pads. Therefore, our results indicate that changing tie pad geometries affected the pressure readings. When there was no lifting of the tie pad relative to the steel plate, negative pressure readings observed in previous tests were no longer present. Therefore, lifting the tie pad relative to the steel plate generates suction pressures in the rail seat-tie pad interface. Changing the position where the load actuator impacts the steel plate promotes changes in the pressure magnitudes. Variations in the tests all showed that the water pressures are directly proportional to the acting forces.