PSI - Issue 64

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

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3.2. Field study #2. Square cross section RC columns. Comparison of the results of the GPR scanning method and ultrasound method on the example of actually performed tests of square section columns in the construction complex in Vladivostok city. These studies are caused by the presence of unconsolidated areas of concrete mixture on the surface of structures due to poor quality compaction during construction works. In the course of concrete works the concrete mixture was dropped from a height of more than 1.5 meters, which provoked its segregation and formation of defects in the form of pores and caverns on the surface of the structures at the bottom of the columns (Figure 5a).

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Fig.5. a – typical defects on the surface of the columns before inspection, b – the view of the inspected column after demounting of the defective concrete cover

Due to the identification of significant defects on the surface of the structures, the columns were ordered to be dismantled. To establish the depth of possible defects formation and to confirm the necessity of dismantling the structures, continuous ultrasonic and GPR studies were carried out on the surface of the investigated columns. There were 9 columns to be investigated in total on this site. By the time of the survey, the concrete cover with visible defects had been demounted (Figure 3b), however, the inspectors were faced with the question of confirming the presence or absence of concreting defects inside the section of the structure.