Test method for determination of the transmission and anchorage lengths in prestressed reinforcement

Abstract

This paper describes a new test method to characterise the bond of prestressed reinforcements to concrete. In order to analyse the bond behaviour in terms of transmission and anchorage, this test method sequentially reproduces on the same specimen of concrete the prestressing transmission and the anchorage when the structure is brought into service. The most outstanding new aspect of the test is that it enables the anchorage length of the prestressed reinforcements to be determined after the transmission of the prestressing force. To prevent the bond phenomenon from becoming distorted, internal measuring devices are not used in the elements to be tested. The test method is representative, reliable, simple and economic. This method can be standardised and is applicable in quality control as an acceptance–rejection test. The basis of the test method and the instrumentation and equipment necessary for implementation are explained, as well as the operative procedure and a comparative analysis of the test reliability compared with other methodologies and the advantages of the new test method.