ISO 22480-2:2022 pdf – Railway applications — Concrete sleepers and bearers for track — Part 2: Prestressed monoblock sleepers

ISO 22480-2:2022 pdf – Railway applications — Concrete sleepers and bearers for track — Part 2: Prestressed monoblock sleepers.
1 Scope This document defines additional technical criteria and control procedures related to the manufacturing and testing of prestressed monoblock sleepers. 2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 22480-1, Railway applications — Concrete sleepers and bearers for track — Part 1: General requirements ISO 22074-8, Railway infrastructure — Rail fastening systems — Part 8: Determination of stiffness 3? Terms? and? definitions For the purposes of this document, the terms and definitions given in ISO 22480-1 apply. ISO and IEC maintain terminology databases for use in standardization at the following addresses: — ISO Online browsing platform: available at https:// www .iso .org/ obp — IEC Electropedia: available at https:// www .electropedia .org/ 4 Symbols and abbreviated terms For the purpose of this document, the symbols given in ISO 22480-1:2022, Clause 4 and the following apply.
5 Bending tests 5.1 General This clause defines the testing regime and rules for the acceptance of prestressed monoblock sleepers. The quality control plan shall define relevant dimensions and tolerances to be checked before carrying out bending tests, in accordance with ISO 22480-1:2022, Table 1. The sleepers for bending tests shall have a surface finish that allows correct execution of the tests. A summary of tests to be carried out is given in Table 1. NOTE For the definition of Method A and Method B, see ISO 22480-1:2022, 5.3.
5.3 Test procedures 5.3.1 General Storage conditions should be specified by the purchaser. The following precautions should be considered for the execution of the tests. — Wipe clean all testing machine bearing surfaces and remove any loose grit or other extraneous material form the surface of the sleeper that will be in contact with the supports. — For sleepers stored in water, wipe excess moisture from the surface of the sleeper before placing in the testing machine. — Place the test sleeper in the machine, correctly centred and with the longitudinal axis of the sleeper at the right angles to the longitudinal axis of the upper and lower supports. Ensure that the reference direction of loading is perpendicular to the direction of casting of the sleeper. For the position of the supports, see 5.2. — Do not apply the load until all supports are resting evenly against the sleeper. The initial reference test loads shall be calculated according to 5.3.2. The test loads shall be applied according to procedures defined in 5.3.3, 5.3.4 and 5.3.5. Crack width shall be measured according to ISO 22480-1:2022, 9.2. NOTE 1 Background information about test load levels for design approval tests and routine tests is given in ISO 22480-1:2022, Annexes A, B and C. Information about the determination of coefficients k 1s , k 1d , k 2s , k 2d and k 3 is given in ISO 22480-1:2022, Annexes B and D.
5.5.2 Bending moment evaluation 5.5.2.1 General These tests are carried out in accordance with the test arrangements in 5.2 and the test procedures in 5.3. Mandatory, optional and not applicable tests are defined in Table 1 for both methods A and B. The number of sleepers to be tested for design approval is defined in 5.5.2.2 to 5.5.2.4. 5.5.2.2 Static tests a) rail seat section: 6 sleepers (one rail seat per sleeper), for the positive bending moment; b) centre section: 3 sleepers for the negative bending moment; 3 sleepers for the positive bending moment. 5.5.2.3 Cyclic test Rail seat section: 6 sleepers (one rail seat per sleeper), for the positive bending moment. 5.5.2.4 Fatigue test Rail seat section: 1 sleeper (one rail seat per sleeper), for the positive bending moment. 5.6 Routine tests 5.6.1 General The routine tests are carried out in order to find any variation in the quality of the concrete sleeper, leading to an unacceptable quality level. The number of samples and rates of tests shall be given in the quality plan for the manufacturing unit. The routine bending tests to be carried out are defined in Table 1. 5.6.2 Positive static test at rail seat section This test shall be carried out in accordance with the test arrangement shown in Figure 1 and the procedure for static positive bending test at the rail seat section without control of the residual cracks.