Experimental assessment of dynamic lateral resistance of railway concrete sleeper

Abstract

The single tie (sleeper) push test (STPT) is a common method to evaluate the lateral resistance of a railway track sleeper. This methodology evaluates the lateral resistance phenomenon in a static manner despite the fact that the majority of the exerted loads on a railway track have a dynamic nature. For this reason, a mass–spring–damper numerical model was created to investigate the dynamic lateral interaction between an isolated sleeper and ballast layer in the presence of various lateral impact loads. On the basis of the model outputs, a pendulum loading test device (PLTD) was designed and developed in the laboratory. In this regard, a cylindrical hammer with modifiable mass and triggering angle was installed on a steel frame for imposing lateral impact load on an instrumented concrete sleeper. The graphs of the sleeper–ballast interaction force versus the sleeper lateral displacement were extracted for different masses and triggering angles of the hammer. Considering a same condition for sleeper, the maximum value of this interaction force was called the dynamic lateral resistance (DLR) and static lateral resistance (SLR) respect to the dynamic and static states of lateral loading. Comparing the values of the sleeper DLRs and SLR indicated that unlike the constant SLR of 6.5kN, the DLR was in the range 2–10.2kN in the impact load domain of 3–40kN. However, as a key finding, the average slopes of the DLR and SLR graphs were equivalent in the dynamic and static tests.