Experimental study on the long-term monitoring of structures

Abstract

The paper deals with the work carried out to check the feasibility of the continuous long-term monitoring of civil engineering structures. Such interest is motivated by the huge activity developed in the last decades in the construction of new infrastructure. The result is a large stock of built structures (bridges, retaining walls,?) that must be maintained and assured with an adequate safety level. First, the proposed overall methodology is presented, leading to the final concept of an smart structure. To this end at least three main aspects have to be solved: damage detection using the adequate system of sensors, expert supervision and, finally, active control. The subject of the paper is mainly focussed in the first aspect with the objective of studying the feasibility of embedding fibre optic sensors in the concrete elements, to see the real performance of those sensors when exposed to aggressive environments normally encountered in concrete structures (chloride, sulphates, CO2), and finally to see the possibility of using the fibre optic sensors in the monitoring of repaired structures too. The tests have shown the accuracy of the measurements obtained in the Bragg grating sensors, either when embedded in the concrete of a new structure or attached to the surface of an existing repaired structure.