Smart Self-Repairing System for Concrete Beams

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The Federal Sustainable Development Strategy is Canada's primary vehicle for sustainable development. It sets sustainable and resilient infrastructure as one of the key development priorities. The nation's drive for sustainability initiates the need to direct research efforts toward developing smart structural systems that adapt with mechanical and environmental loads. Smart structures mimic human muscular and nervous systems, where the system and its related component form an entity that behave in a pattern that emulates a biological function. The objective of the proposed research is to develop a smart self-repairing system for concrete beams experiencing deficiencies (cracks and excessive deformation) at normal operating loads. The system is composed of Shape Memory Alloy (SMA) wires embedded inside a reinforced concrete beam and connected to an electric current supply. The SMA is a smart material that tends to contract when subjected to heat applied via an electric current. Restraining the material by mechanical anchors at both ends will lead to the development of tension force in the SMA, and hence a post-tensioning effect. This mechanism will improve the structural performance by pulling the two sides of a crack in a concrete beam and reduce the member's deflection under applied loads. The system will be developed in three sequential stages; system design, system verification, and system reliability. The components of the self-repair system including material characterization, SMA anchorage , stress losses, and temperature effects will be examined in the first stage by small-scale testing and numerical simulation. The design recommendations pertaining to the first stage will feed into the second stage in which large scale-testing, constitutive modeling, and numerical simulation will be used to verify the system response for flexural- and shear-governed beams. The third stage is concerned with examining the reliability of using the system in the design of real-life concrete frames. The risk of adapting the new technology will be quantified using structural reliability methods and compared with the safety standards of the National Building Code of Canada. New concrete structures built with the self-repair technology will most likely not require structural repairs during their service life. This will reduce the maintenance cost of our infrastructure which accounts up to 80% of the total cost over the lifetime of the project as per the findings of a study conducted in 2015 by the Standing Committee on Transport, Infrastructure and Communities at the House of Commons. Implementing the new technology can also reduce the carbon footprint that result from producing and installing strengthening materials during structural maintenance. With the increased demand for professional engineers and researchers working in the field of sustainability, graduating HQP specialized in the broad area of structural assessment and repair is beneficial to the Canadian economy.