Experience in investigating the state of concrete in hydraulic structures

Conclusions

• 1. Instrumental investigations of concrete structures of the Tsimlyansk, Kegum, and Plavinas hydrostations after respectively 35, 50, and 25 years of operation showed that the concrete of the structures of these hydrostations is in a satisfactory state. On-site tests by the ultrasonic method, standard Kashkarov hammer, and cores on a press showed an excess of the compressive strength of concrete in the investigated structural members of the structures by 1.25–3.0 times compared to the standard values for the design grades. At the same time, on individual structures such as the dam spillways at the Tsimlyansk hydrostation, piers of powerhouses and dams, and dividing walls of stilling basins, in the lower pools of the investigated hydrostations there are local and zonal concrete damages and baring of the reinforcement. In these places it is necessary to carry out repair and restoration works. The fishway at the Kegum hydrostation requires overhaul.

• 2. For safe operation of the flood-control outlet of the Charvak hydrostation, it is necessary to make check calculations of the stability of the shaft lining with consideration of the cavitation and hydrodynamic effect of the flow for the real strength of concrete corresponding to class V22.5 and to seal cavities in the concrete and smooth out the projections of the block joints of the shaft lining of the FCO

• 3. For the Azerbaijan tunnel, it is necessary to additionally make a concrete lining to increase its water impermeability.

  The low physical and mechanical characteristics of the concrete of the investigated Charvak hydrostation and Azerbaijan regional power station are explained by the low quality of concreting and poor quality control of the concrete by the appropriate services during construction

• 4. On the whole the investigations made it possible not only to determine the properties of concrete of the structures but also to determine the scope of repair works and technology of their restoration.