PSI - Issue 11

Iara Silva et al. / Procedia Structural Integrity 11 (2018) 130–137

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Iara Silva et al./ Structural Integrity Procedia 00 (2018) 000 – 000

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in Fig. 5, to distinguish this type of sleeper from the others. They were then stored and are currently awaiting installation on low-traffic and low-speed rail lines.

Fig. 5. Identification of recovered sleepers

7. Tests for quality control

In order to verify the efficacy of the recovery method and to confirm that the causes of the failures were not structural, 2 sleepers were randomly selected from each batch of 1,000 recovered sleepers for the purpose of performing static tests for quality control, the same ones performed for the conventional sleepers. The tests described as follows are in compliance with the Manual for Railway Engineering, 2013 from AREMA (American Railway Engineering and Maintenance-of-Way Association) and the Brazilian Standard NBR 11709: Concrete Sleeper - Design, Materials and Components from ABNT (Brazilian Association of Technical Standards). For tracks with 1600 mm gauge and 40 tons axle load. The verifications and tests performed are described below:

7.1. Positive Moment on Rail Support Test

In this test, a load with a maximum rate of 22 kN/min was applied to the sleeper support (Fig. 6) until the P value was reached, equal to 261.71 kN, producing a positive design moment in the rail support of 41.630 kN.m. This load was maintained for three minutes during which time an inspection using illuminated magnifying glass was carried out, with a magnification capacity equal to five times, to verify the occurrence of structural cracks in the concrete.

Fig. 6. Positive Moment on Rail Support Test Execution

7.2. Fasteners Fitting Test

The fasteners incorporated into the concrete sleeper during its manufacture were subjected to torque and pullout tests. In the Pullout test, a load of 53.4 kN was applied to each insert separately, maintained for 5 minutes, according to Fig.7.a. During this period, inspections were carried out to verify the presence of some sliding of the embedded