## 4 Results and Discussion  
As a result of automated data approximation, one-factor mathematical models were obtained. Each measurement was performed 20 times. The confidence probability is P = 0.95, and the Student's distribution quantile is t = 2.0098 for a given confidence probability with the number of degrees of freedom. The relative measurement error is \(\delta=3.5\%\). The beam after testing is shown in Figure 13.  
The data on the dependence of optical power loss on press pressure were obtained (Figure 14). Figure 12: Image of a negative light spot from a computer screen. Figure 13: A laboratory sample of the beam after testing. The optical power loss of a fiber with a wavelength of 650 nm depends on a step-by-step increase in the pressure force of the press. In the course of the experiment, it was found that the increase in pressure on the beam led to an increase in additional losses formed in the optical fiber. Since the fiber was subjected to mechanical bending, part of the radiation that went beyond the shell, respectively, was lost. It was found that there is a direct correlation between the structural force (beam deformation) and the intensity of the light optical spot formed on the surface of the photo matrix. Accordingly, there is a direct correlation between the structural force and the level of additional losses in the optical fiber. The intensity of the optical radiation spot formed on the surface of the photomatrix decreases in direct proportion to the value of the applied pressure at the center of the tested reinforced concrete beam, and additional losses of optical radiation power increase. The observed process is related to the photoelastic effect, as the optical fiber undergoes microbending during the deformation of the reinforced concrete beam. Accordingly, the optical wave transmission parameters change due to changes in the refractive index between the sheath and the fiber core. It is known that amplitude sensors are simpler in contrast to phase-sensitive sensors. This will make it possible to create a relatively simple in-design system with a low manufacturing cost since it does not use expensive electron-optical components, for example, an optical circulator, as in [39; 40]. Unlike the known optical interferometry methods [28; 29; 30], the proposed system is insensitive to external temperature fluctuations, which is very important for noise immunity since the working conditions are the observed temperature fluctuations of a real construction object. The proposed system uses optoelectronic analysis, which analyzes video images, which provides simplicity in the sensor design and reduces the cost of the system as a whole in contrast to Bragg gratings embedded in the optical conductor [24; 25; 26], which require analysis of the reflected spectrum using an expensive spectrum analyzer. The low price will allow for implementation during construction. Laboratory tests of the system have shown that the number of channels can be increased to 16 or 32. The number of channels depends on the computing power of the microprocessor device and can be increased if more channels are needed. Currently, a four-channel monitoring system is being developed, which will allow control of the building structure in four zones. The length of each zone will be 50 m. The main difference between the proposed method and other methods is the optoelectronic analysis of the optical wave passing through the sheath of the optical fiber, unlike analogs, which monitor changes in the intensity of the light wave passing through the core of the optical fiber. Unlike the multi-pixel photodetector, the use of a multi-pixel one allows estimating the intensity over the entire area of the light spot coming out of the optical fiber and falling on the surface of the photodetector. The experiments showed that the stronger the impact on the fiber-optic sensor, the more white pixels were formed on the system's screen.