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Measurement of Localized Deformations in High-Strength Steel Cables

Measurements of deformations in monostrand steel cables experiencing axial and transverse deformations is challenging due to their complex geometry and difficulties with the placement of strain gauges in the vicinity of the anchorage. Nevertheless, quantitative information on local strains is often required to evaluate the fatigue resistance of steel monostrands. This paper focuses on the application of a digital image acquisition and analysis technique to determine deformations and resulting strains in the vicinity of the strand anchorage. In a previous study, the applicability of the image analysis technique was demonstrated on pretensioned high-strength steel monostrand specimens, which indicated good agreement between the wire strains measured using image analysis and those measured by conventional strain gauges. The current study focuses on the comparison of deformations within the strand induced by static inclination of the bearing plate (as stipulated in the PTI and fib evaluation guidelines) and the strains due to actual transverse displacements of the strand. Results of this parametric experimental study show that axial fatigue tests with inclined bearing plates to induce local bending deformations are not realistically simulating the behavior of the monostrands at the anchorage. The local strain ranges induced by the above-described test setup are considerably different from those caused by transverse displacements of the strand. Furthermore, the strain information obtained with the image analysis technique is used in the identification of potential fatigue failure modes in monostrand cables.

1. Fédération internationale du béton (fib). “Bulletin 30 Acceptance of stay cable systems using prestressing steel,” 2005. 2. Post Tensioning Institute (PTI). PTI Guide Specification. Recommendations for stay cable Design, Testing and Installation. 2007. 3. SETRA Cable Stays Recommendations of French Interministerial Commission on Prestressing. “Haubans - Recommandations de la CIP,” 2002. 4. Rodríguez, G. and C.J. Olabarrieta. “Fatigue Testing with Transverse Displacements in Stay Cable Systems,” Proceedings of the 3rd fib International Congress, Washington, 2010. 5. Winkler, J., G. Fischer, C.T. Georgakis and A. Kotas. “A Preliminary Bending Fatigue Spectrum for Steel Monostrand Cables,” Journal of the International Association for Shell and Spatial Structures (ISSN: 0304- 3622), Vol: 52, Issue: 4, pp: 249-255, 2011. 6. Wood, S. and K.H. Frank. “Experimental investigation of bending fatigue response of grouted stay cables,” Journal of Bridge Engineering, Vol:15, pp:123-130, 2010. 7. Winkler, J., G. Fischer and C.T. Georgakis. “Localized bending fatigue behavior of high-strength steel monostrands,” Proceedings of the 6th International Conference on Bridge Maintenance, Safety and Management IABMAS 2012, Stresa, 2012. 8. Gourmelon, J.P. “Cable fatigue behavior as a major safety factor in cable-stayed bridges,” Bulletin des Laboratoires des Ponts et Chaussees, pages: 53-71, Issue: 244-245, 2003.
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