Influence of the storage conditions on prestressing steel relaxation losses
DOI:
https://doi.org/10.3989/mc.2012.04011Keywords:
steel, relaxation losses, coiling, storageAbstract
Stress relaxation losses on active reinforcement have significant impact on prestressed concrete structures. This is why relaxation tests are carried out on prestressing steel wires and strands after being manufactured. Then, these materials are coiled and stored for a long-term period, sometimes in excess of one year. The influence of these operations, carried out after manufacturing, is usually neglected. Nevertheless, some manufacturers and contractors have noticed that, sometimes, when relaxation tests are carried out after a long-term storage, the relaxation losses found are higher than those measured immediately after manufacturing. In this work, lab tests are performed to check the influence of the coiling radius and the period of storage on the relaxation test. In addition to this, an analytical model is presented to predict the results of a relaxation test carried out on a wire coiled and stored for a long-term period. This model explains the evolution on the cross-sectional stress profile along the coiling-storing-uncoiling process, as well as the influence of the residual stresses on it.
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(1) EN ISO 15630-3 (2010) “Steel for the reinforcement and prestressing of concrete - Test methods”.
(2) ASTM E328-86 e1: “Standard Test Methods for Stress Relaxation Tests for Materials and Structures”, (1996)
(3) EHE-08. Instrucción de Hormigón Estructural. Publicaciones del Ministerio de Fomento. Secretaría General Técnica.
(4) Elices, M.: “Influence of residual stresses in the performance of cold-drawn pearlitic wires”. Journal of Materials Science, vol. 39, nº 12 (2004), pp.3889-3899. http://dx.doi.org/10.1023/B:JMSC.0000031470.31354.b5 http://dx.doi.org/10.1023/B:JMSC.0000031470.31354.b5
(5) Atienza, J.M.; Elices, M.: “Influence of residual stresses in the stress relaxation of cold drawn wires”, Materials and Structures, vol. 37, (2004) pp. 301-304.
(6) Sánchez-Gálvez, V.; Elices, M.; Astiz M.A.: “A new formula for stress relaxation in steels”. Materials and Structures, vol. 9, nº 54 (1976), pp. 411-417.
(7) Sánchez-Gálvez, V.: Elices, M.; “The relationship between tensile strain, creep and stress relaxation in cold-drawn steels at low temperatures”. Materials Science and Engineering, nº 78 (1986), pp. 1-8.
(8) Etienne, C.F.; Van't Spijker, F.: “The influence of prestretching on the relaxation properties of cold drawn wire for prestressed concrete”. Cement, (1967)
(9) Magura, D.: Sozen, M.; Siess, Ch.: “A study of stress relaxation in prestressing reinforcement”. PCI Journal, (1964), pp. 13-57.
(10) Elices, M.; Suárez, F.; Gálvez, J.C.; Cendón, D.A.; Atienza, J.M.: “Influence of coiling on the stress relaxation of prestressing steel wires”, Structural Concrete, vol.12, nº2 (2011), pp. 120-125.
(11) Fib. Bulletin 55. Model code 2010. First complete draft, vol. 1. Section 5.3.6, pp. 187-190.
(12) Ruiz-Hervías, J.; Atienza, J.M.; Elices, M.; Oliver, E.C.; “Optimisation of post-drawing treatments by means of neutron diffraction”, Materials Science and Engineering A, vol. 480 nº 1-2 (2008), pp. 439-448. http://dx.doi.org/10.1016/j.msea.2007.07.017
(13) Atienza, J.M.; Ruiz-Hervías, J.; Martínez-Pérez, M.L.; Mompeán, F.J.; García-Hernández, M.; Elices, M.: “Residual stresses in cold drawn pearlitic rods”. Scripta Materialia, vol. 52 (2005), pp. 1223-1228. http://dx.doi.org/10.1016/j.scriptamat.2005.03.003
(14) Martínez-Pérez, M.L. et al.: “Residual stress profiling in the ferrite and cementite phases of cold-drawn steel rods by synchrotron X-ray and neutron diffraction”. Acta Materialia, vol. 52 (2004), pp. 5303-5313. http://dx.doi.org/10.1016/j.actamat.2004.07.036
(15) Atienza, J.M.; Elices, M.: “Role of residual stresses in the stress relaxation of prestressed concrete wires”. Journal of Materials in Civil Engineering 19:8, (2007), pp. 703-707.
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