PSI - Issue 64

Alexander Shuvalov et al. / Procedia Structural Integrity 64 (2024) 445–455 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

452

8

a

b

Fig.7. a - the surface of the columns before inspection, b – the process of ultrasound sounding of concrete columns

According to the results of ultrasonic research, the values of ultrasonic velocity throughout the height of the investigated columns are in the range from 4444 to 4580 m/s, the variation of single values of ultrasonic velocity from the average readings is 7.5%, which indicates the homogeneity of the concrete structure within the cross-section of the columns and the absence of defects. The values of ultrasound velocity in column sections do not vary significantly in height, and are within acceptable limits. A pattern has been noted for a decrease in average ultrasound velocity from lower zones of column sections (4637 and 4574 m/s) to upper zones (4493 and 4382 m/s). This is normal for vertically cast-in-place reinforced concrete structures, and is due to the compaction of concrete under its own weight during the liquid phase.

Table 3. Numerical values of ultrasonic wave velocity on one of the investigated columns

Average value of ultrasonic penetration velocity over the whole structure, m/s

Height of section location from the bottom of the column, m

Range of average ultrasonic ultrasonic velocity, m/s

Average value of ultrasonic ultrasonic velocity on the section, m/s

0-1 1-2 2-3 3-4 4-5 5-6 6-7

4632-4800 4604-4756 4475-4619 4486-4532 4462-4564 4449-4496 4431-4494

4704 4712 4541 4507 4516 4469

4557

4451 According to the work program, GPR studies were to be performed on all planes of structures. GPR measurements were carried out in the vertical direction along the entire length of the column. It is worth noting that no preparatory work was required for the GPR method, except for the installation of the scaffolding for access to height. In fact, GPR scanning can be performed even at some distance (depends on the length of sounding EM-wave) from the surface under study. GRP profiles were positioned between the longitudinal reinforcement bars to minimize the influence of metal reinforcements. It is also worth noting that more column cross-sections were covered by the GPR routes than