Annual Report 1999/2000

Research Achievements Fibre Optic Sensing Several important breakthroughs have occurred in the area of fibre optic sensing. One discovery is that Bragg grating sensors can provide information on strain distribution along the grating, which leads to a self-diagnostic capability that is unrivalled by any other kind of structural sensor. This is particularly useful in the development of smart anchorage and smart repair patches. Another breakthrough has been the development and field application of a localized fibre interferometer sensing system which, to our knowledge, is the first of its kind used in an application of this nature. One of the most significant advances made involves a new method for measuring strain profiles. The distributed sensing system which can achieve this features a distributed feedback tunable laser, a current driver, an optical system, three photo-detectors and the sensor itself. Two high-speed data acquisition boards operating in a conventional desktop Pentium PC acquire the data. This is a significant advance. The long gauge fibre optic sensor is also proving to be a reliable measuring device for monitoring deformations of structures over gauge lengths varying from 1 to 30 metres. Remote Monitoring ISIS Canada's ability to launch major field demonstration projects provides numerous opportunities to conduct research on structural health monitoring. Five years ago, measuring devices had to be transported to the site when readings were required. Over the past three years, remote monitoring techniques have been developed using lasers, fibre optic sensors, wireless telecommunication, and remote data collection and processing. Everything that has been accomplished in remote monitoring research is considered a breakthrough, as none of it had been achieved prior to ISIS Canada. A software package for monitoring structures, which is currently available to all ISIS field-monitoring teams through the Internet, is just one example. Data collected and analyzed over the next few years will dramatically alter the design of civil engineering structures. Another component of this research theme is the development of smart reinforcements and connectors. A major breakthrough occurred when it was demonstrated that pultrusion technology could allow the incorporation of fibre optic sensors within FRP reinforcements. Instead of attaching fibre optic sensors to reinforcement surfaces during construction, the FRP reinforcements arrive at the construction site with the optical fibres and sensors already contained within the component. This unique technology, which has never been used before, has been installed in demonstration bridges in Nova Scotia, Alberta and British Columbia. This new product is now being manufactured in Quebec. Innovative Structures This research theme encompasses a wide range of applications including innovative designs and configurations of structural components, development of the steel-free deck technology, a new anchorage system for FRP strands for masonry structures, an innovative FRP ground anchorage, hybrid FRP designs, FRP dowels for concrete slab joints, and the development of FRP transmission poles. The Taylor Bridge in Headingley, Manitoba is believed to be the first bridge of its type in the world to have carbon FRP shear stirrups. Four Canadian highway bridges have been or are in the process of being built with FRP reinforced decks. These bridges are the first of their kind anywhere in the world, each incorporating FRPs in new configurations, such as cantilever overhangs of the deck, continuity of spans longitudinally, and precast concrete girders. A breakthrough occurred with the development of an innovative FRP potted ground anchor system that takes advantage of the non-corrosive characteristics of FRPs and has the capacity to utilize the full tensile strength of FRP tendons. This innovative approach is a promising system for industrial applications. Similarly, the development of a corrosion-free anchorage system for masonry structures is another advancement which has been patented. Rehabilitated Structures Research on rehabilitated structures focuses on the crucial aspects of performance, durability and corrosion. In the process, sensing devices capable of remote monitoring for damage and deterioration are being developed. A basic breakthrough in this area is the opportunity to test laboratory results in field demonstration projects. The most significant advances in field research have been with regard to the optimization of FRP repair and strengthening schemes for existing concrete structures. Significant advances have also been made in the use of FRPs for enhancing the shear flexural behaviour of reinforced concrete beams. In the process of conducting research in this area, improved laboratory accelerated corrosion techniques have been developed. Also, a novel specimen fabrication technique was developed for the expedient simulation of chloride penetration. Field demonstration projects to date have shown that construction crews can easily carry out the rehabilitation of structures with FRPs and that the cost is less than for conventional construction methods. Widespread acceptance of FRP wraps for structural rehabilitation would constitute a huge breakthrough for ISIS technology. Progress continues in this regard. Work in all ISIS Canada research themes is breaking new ground at every step and a multitude of milestones have been exceeded along the way.

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