Diving examination

Hydro Structures of industrial and energy sites are involved in the technological cycle of hazardous industrial sites and are considered a particular threat to people and the environment, because in case of an accident they are not only sources of hydrodynamic impact, but also sources of pollution of surface waters, groundwater, territories, and the air. Accidents at hydro structures are one of the most dangerous in terms of consequences and swiftness.

Tandem Project, LLC is one of the organizations that have the necessary equipment, qualified personnel, appropriate permissions for this type of work, which can be accomplished using divers and remotely controlled underwater apparatus.

The diving examination methods are based on general approaches to the inspection of the underwater part of hydro structures, as well as many years of experience in organizing diving visual, instrumental, and instrumental surveys.

Examination works begin with the development of the Survey Program and its coordination with the customer.

Inspection of the underwater part of the hydro system is carried out in compliance with all labor safety requirements using the following methods:

A) The visual method:

External examination and a diving inspection using photo and video technology (detection of surface corrosion, biofouling of structures, cracks, and other types of decay of concrete structures, erosion of soil foundations, landslides on slopes, accumulation of silt deposits and foreign sites in the water area. In the absence of direct safe access at the inspected site, remotely controlled underwater apparatus are used);

B) The instrumental method:

Inspection of the seabed and slopes by sound navigation ranging (Monitoring of the bottom surface, location of foreign sites on the bottom; if the general condition of the structures is found to be satisfactory, the strength of the concrete is studied selectively (at least in 10% of the structures) by a non-destructive testing method using an ultrasonic device).

In case safe direct access of the diver at the inspected site is limited, remotely controlled underwater apparatus equipped with video cameras and measuring devices are used.

The examination is an inspection of structures by a diver with the performance of instrumental measurements (ruler, caliper, hammer, dipstick) in order to determine the parameters and qualitative signs of the technical condition at sites at the time of the study. If necessary, individual sections of the structure are cleaned from biofouling and corrosion for a more thorough inspection.

The results of the diving inspection, conclusions about the technical condition of hydro structures, reasons for the appearance of defects and damages, recommendations for improving the condition of structures, suggestions for further operation and repair of the structures of underwater parts surveyed by the hydro structures necessary to maintain the resource of building structures are drawn up by the technical report.

The technical report contains:

• The list of examined structures and sites;
• The timing of the inspection;
• Technical characteristics of examined sites;
• Data on the operating conditions of building structures;
• Data on previous inspections, repairs, and reconstructions since the beginning of operation;
• Results of visual inspections and instrumental measurements (video recordings of defects, cross-sections of linear structures);
• The list of used equipment and measuring instruments;
• The statement of structural defects, type, location, and size;
• The results of non-destructive structure testing;
• Conclusions on the technical condition of structures, the degree of wear and decrease in the capacity of the main bearing and enclosing structures;
• Recommendations and technical solutions, suggestions for the restoration or reinforcing of hydro structures and improvement of operating conditions;
• Conclusion on the state of the investigated structures of the underwater parts of the hydro system and the technical feasibility of their further use;
• Photo and video materials of the underwater inspection.