Contribution à l'instrumentation des ouvrages en béton application des fibres optiques pour la mesure des déformations internes
Surveillance of large engineering structures, especially large dams, is of great concern among designers as well as for managers. The expression""dam security"", now common for dam technicians, engineers and managers, includes many specific aspects: public security, environment protection and economy. Also, the consequences of large dam failure or damaging are losses in all aspects already mentioned. Keeping track of the changing state of dams, often related to the aging of structure concrete, is quite important regarding security aspects. Fiber optic sensors technology is expanding very rapidly. The particular interest of this technology is the possibility to install efficient sensors at locations difficult to reach. The sensitivity of these sensors and their fast response allow, among other things, to measure small strains and cyclic behavior. Regarding geotechnical and structural instrumentation, this technology gives rise to many perspectives. Among many research avenues, development of a simple internal strain detection probe for specific application in concrete dam monitoring is proposed. This research theme is a continuation of the Cylindre instrumenté de l'Université de Sherbrooke (CIUS) development. Application of fiber optics and real time monitoring system to dam instrumentation could be hold as the originality of the present work. Actually, working on the design of small fiber optic and vibrating wire strain measuring probe is the main task. Installed in dams, this type of probe would allow an accurate real-time monitoring of the global or local behaviour of the structure and also, eventually, remote monitoring. Design of the proposed device first begins with a validation, in laboratory and on site, of the new fiber optic sensor technology for concrete instrumentation. Results show that the embedded Fabry-Pérot sensors allows to monitors internal strains in concrete because the modification of the properties of the surrounding concrete is negligible. Temperature is of less effect on the embedded sensor and correction factors are unnecessary. Finally, development of an internal strain measurement probe is possible with this new type of strain gauge.
- Génie – Thèses