Investigation of adaptive prestressing for concrete structures

Current practice in the design and construction of civil infrastructure is to create 'passive' components and systems. The structural system is fixed at the time of initial construction and remains unchanged throughout the life of the structure unless purposeful intervention is taken. This project challenges the concept that our structures need to remain passive in the future. Through combining advances in materials and sensing technology, the concept of actively controlling and changing the structural system in response to changing loading conditions will be investigated. Specifically technology for adaptive prestressing of concrete beams will be developed. The beam will be constructed of concrete but will have an internal steel tendon which can be stressed to any desired level of tension in response to loads being applied to a beam. Using a biological analogy, the tendon will be similar to a muscle in the body; it will be relaxed when there is no load but will contract when load is present. The amount of contraction will change in response to the amount of load being applied. This concept active or adaptive control will revolutionize the way we conceive of and create future structural systems. The short-term objectives of the project are to establish the ability of adaptive systems to control service level behaviour, improve ultimate load response, reduce prestress losses and provide for optimum beam dimensions. In the broader context, the project will help achieve a Canadian national strategic research objective of creating smart systems and technologies which promote the use of advanced materials and sensing technology to produce new design and management solutions for physical infrastructure.