Numerical verification of the saw-cut method

In Slovakia and other countries, a contemporary challenge for engineers and academics is an assessment of the state of existing prestressed concrete structures. The main components of assessment include regular inspections, maintenance, and diagnostics. For defining the load-carrying capacity and remaining service life, more reliable results of diagnostics are required. A need for detailed knowledge of the actual value of prestressing force is becoming a crucial aspect of civil engineering. There are many prestressed concrete structures built in the previous century which are about reaching their limit of service life. These structures are about sixty years old and many of them are exhibiting signs of deterioration due to the design and construction deficiencies, such as overloaded vehicles, environmental distress, and inadequate maintenance. In this paper, dozen concrete specimens are numerically analysed using the indirect non-destructive Saw-cut method. Ten of them are loaded by different level of compressive force which initiates compressive stress from 2.0 MPa to 12.0 MPa. Performed numerical analysis is an important basis for the experiment. The influence of temperature change caused by sawing will be later experimentally investigated on the remaining two concrete specimens. For numerical analysis, a 2D finite element model with the assumption of nonlinear material behaviour is performed. Subsequently, the correlation between the distance and depth of the saw-cuts, and amount of released strain or stress, as a result of numerical analysis, is outlined. Finally, the outputs obtained from numerical analysis are discussed and recommendations for the experiment are summarized.