An innovative approach to achieve re-centering and ductility of cement mortar beams through randomly distributed pseudo-elastic shape memory alloy fibers

N. Shajil; S. M. Srinivasan; M. Santhanam

doi:10.1117/12.915829

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28 March 2012 An innovative approach to achieve re-centering and ductility of cement mortar beams through randomly distributed pseudo-elastic shape memory alloy fibers

N. Shajil, S. M. Srinivasan, M. Santhanam

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Proceedings Volume 8342, Behavior and Mechanics of Multifunctional Materials and Composites 2012; 83421K (2012) https://doi.org/10.1117/12.915829
Event: SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring, 2012, San Diego, California, United States

Abstract

Fibers can play a major role in post cracking behavior of concrete members, because of their ability to bridge cracks and distribute the stress across the crack. Addition of steel fibers in mortar and concrete can improve toughness of the structural member and impart significant energy dissipation through slow pull out. However, steel fibers undergo plastic deformation at low strain levels, and cannot regain their shape upon unloading. This is a major disadvantage in strong cyclic loading conditions, such as those caused by earthquakes, where self-centering ability of the fibers is a desired characteristic in addition to ductility of the reinforced cement concrete. Fibers made from an alternative material such as shape memory alloy (SMA) could offer a scope for re-centering, thus improving performance especially after a severe loading has occurred. In this study, the load-deformation characteristics of SMA fiber reinforced cement mortar beams under cyclic loading conditions were investigated to assess the re-centering performance. This study involved experiments on prismatic members, and related analysis for the assessment and prediction of re-centering. The performances of NiTi fiber reinforced mortars are compared with mortars with same volume fraction of steel fibers. Since re-entrant corners and beam columns joints are prone to failure during a strong ground motion, a study was conducted to determine the behavior of these reinforced with NiTi fiber. Comparison is made with the results of steel fiber reinforced cases. NiTi fibers showed significantly improved re-centering and energy dissipation characteristics compared to the steel fibers.

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N. Shajil, S. M. Srinivasan, and M. Santhanam "An innovative approach to achieve re-centering and ductility of cement mortar beams through randomly distributed pseudo-elastic shape memory alloy fibers", Proc. SPIE 8342, Behavior and Mechanics of Multifunctional Materials and Composites 2012, 83421K (28 March 2012); https://doi.org/10.1117/12.915829

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