Full-scale fatigue test of unit-plate ballastless track laid on long-span cable-stayed bridge

摘要

This paper provides the experimental research on the fatigue behaviors of unit-plate ballastless tracks laid on long-span cable-stayed bridge. A set of loading devices for full-scale track structures were fabricated, and then a series of full-scale fatigue tests were conducted. The loading frequency was about 2.5-2.8 Hz, the fatigue loading range was 50-255 kN, and the loading cycle was set as 5 x 10(6) times. Furthermore, a series of post-fatigue static loadings were applied on full-scale ballastless track under certain loading cycles. Some conclusions were as follows: It was observed that by applying the train axle load at the middle of track slab, a very low stress level was created in ballastless track, and no obvious variation in stress value was observed by increasing loading cycles. For track slab end, interlayers tended to warp up relatively, and interlayer pressure was decreased. Due to the presence of rubber isolation layer, no voids and gaps were formed at interlayers of unit-plate ballastless track. Besides, load-interlayer deformation and pressure variation curves showed obvious non-linearity by increasing post-fatigue loading, and these curves had large overlapping zones. Furthermore, there was no obvious enhancement or degradation observed in ballastless track stiffness by increasing fatigue loading cycles. (C) 2020 Elsevier Ltd. All rights reserved.