Assessment of Dynamic Lateral Resistance of Concrete Tie Using Pendulum Loading Test Device

Tie lateral resistance is one of the key parameters ensuring track lateral resistance and track stability in horizontal plane. Single tie push test (STPT) is the most common method to determine the static lateral resistance (SLR) of a single tie in ballasted tracks. The most important weakness of this test is evaluation of the SLR. Since the transferred force by train wheel to the rails has a dynamic nature, evaluation of SLR by STPT seems questionable; hence, for obviating the mentioned deficiency in STPT, in the present study, an innovative pendulum loading test device (PLTD) was designed and developed for assessing the dynamic lateral resistance (DLR) of single tie. By using the PLTD, a hammer is released with adjustable weights and triggering angels to impact on lateral side of sleeper and consequently, the tie lateral displacement as well as its acceleration are recorded. To prevent concrete tie breakage due to hammer impact, an elastomeric pad is attached at the end of tie. The tests’ results with different impact weights and triggering angels are presented as load-displacement diagrams corresponding to real wheel load as a design tool. Also, the results of this study were compared to some other STPT tests under similar conditions. The results of this comparison showed that despite constant lateral resistance of 6.5 kN in the STPT test, the corresponding force of 2 mm displacement in pendulum test varies from 2 to 31 kN. Finally, it was proved that the DLR/SLR ratio is in the range of 0.3-4.9, which can be used for practical purposes.