PSI - Issue 48

Igor Shardakov et al. / Procedia Structural Integrity 48 (2023) 127–134 Shardakov et al/ StructuralIntegrity Procedia 00 (2023) 000 – 000

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3.1. Inclinometry unit The spatial position of the structure is additionally controlled by the inclinometry unit. It contains 6 high precision inclinometer sensors: 5 on one carrier column and 1 on the adjacent one (Fig. 2b). Tilt angle measurement limits are ±3600 arc. sec; measurement error is 0.5 arc. sec. Graphs in Fig. 4 show the deviation from the initial position of the structure in the horizontal plane at different heights. Horizontal displacement data obtained from sensors located at different heights make it possible to calculate the actual spatial shape of the structure. As a result, we can obtain an important controlled parameter - deviation of the structure from its original position at the level where the lifting mechanism is located.

Fig. 4. Change in tilt angles at the control points of the structure [arc. sec.] from 14.08.2020 to 14.01.2021.

3.2. Strain gauge unit and temperature measurement unit

The block of strain gauges allows controlling axial deformations in the most loaded sections of support columns. The unit contains 19 strain gauges located on the bearing columns (Fig. 2a), power lines for the gauges, multichannel recorders and communication lines with a local data collection and processing station. The range of registered strain is from – 3000 µm/m to +3000 µm/m. Registration accuracy is ±3 µm/m . Fig. 5 shows an example of readings of one strain gauge for 5 days of observation. The sensor is placed on a column C7 resting on the concrete head of the shaft. Our observations have shown that strain gauges reflect changes in the structure at different time scales. Thus, the strain gauge readings change according to daily temperature fluctuations. Fig. 5 compares the readings of the strain gauge and the temperature sensor located on the same column C7. At the same time, the readings of some sensors respond to structural vibrations caused by certain technological operations. In addition, significant changes in deformations are observed over a longer interval. These observations confirmed the need to control the temperature of the main structural elements. 7 temperature sensors are placed on the structure in the same positions as the strain gauges (Fig. 2a).