Investigation of adaptive prestressing for concrete structures

目前民用基础设施的设计和施工实践是创建“被动”组件和系统。结构体系在初始施工时是固定的，除非采取有目的的干预措施，否则在整个结构寿命期间保持不变。这个项目挑战了我们的结构在未来需要保持被动的概念。通过结合材料和传感技术的进步，主动控制和改变结构系统以响应变化的载荷条件的概念将被研究。具体而言，将发展混凝土梁自适应预应力技术。梁将由混凝土建造，但将有一个内部钢筋，它可以在响应施加在梁上的负载时，被强调到任何期望的张力水平。用一个生物学上的类比，肌腱将类似于身体的肌肉；当没有负载时，它会放松，但当有负载时，它会收缩。收缩量将根据所施加的载荷量而变化。主动或自适应控制的概念将彻底改变我们设想和创造未来结构系统的方式。该项目的短期目标是建立自适应系统的能力，以控制服务水平的行为，改善极限荷载响应，减少预应力损失，并提供最佳的梁尺寸。在更广泛的背景下，该项目将有助于实现加拿大国家战略研究目标，即创建智能系统和技术，促进先进材料和传感技术的使用，为物理基础设施提供新的设计和管理解决方案。

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.