Experimental Studies of Laboratory Samples of Fiber-Optic Sensors within Reinforced Concrete Building Construction. Part 2: The Experiment

Design of control tools for the timely identification of hidden defects in monolithic reinforced concrete foundations, beams, and other extended building structures requires experimental studies of fiber-optic sensors (FOS) in monitoring systems. In the first part, an overview of experimental studies related to the monitoring of building structures using FOS was carried out. This paper discusses our experiments on the observation of the technical condition of building structures. The optimal parameters of the monitoring system are proposed. It is shown that under mechanical stress on FOS, the spectrum of the light spot changes. This makes it possible to determine the exact numerical values of the deformation. The use of optical fiber of the G652 standard as a distributed source for continuous monitoring of the condition of buildings and structures allows monitoring changes in the parameters of mechanical loads, stresses, and deformations. The dependence of the destruction of the optical fiber material with the cyclic load factor is founded. The main factors in the development of fatigue cracks in optical fiber are the amplitude of stresses and deformations, the duration of loading cycles. The results convincingly show that by means of quasi-distributed sensors it is possible to reliably identify the damaged area, and using the optical reflectometry method to determine the place of destruction with an accuracy of one meter.