Role of NDE in quality control during construction of concrete infrastructures on the basis of service life design

Abstract

The performance and reliability based service life design follows the same principle and framework as the performance based structural design. It is based on terms such as performances, limit states, reliability and reference period or design service life. As in the structural design, during the service life design, the uncertainty is taken into account in the probability density functions of the basic variables, including their parameters like the mean value and the standard deviation. This means that during construction and use of the structure, measures must be taken to guarantee that the uncertainties do not exceed acceptable limits. Testing and quality control is therefore important at several stages during the life of a structure. To check the real performance of the structure, the material properties, the geometrical and execution variables that influence the selected degradation models have to be checked by quality control in order to define and to update the statistical quantities (type of distribution, mean value, standard deviation) of the stochastic variables that affect structural reliability. It is demonstrated in this paper that the selected non-destructive evaluation (NDE) method (so called ‘Two point Electrode Method’) has been successfully applied in relation to the service life design during the construction of the ‘Green Hart Tunnel’. For this purpose a statistical model has been developed in order to derive practical criteria, which can be easily used in practice. Further studies have been concentrated on seeking other potential NDE methods, which can be applied in a real structure to measure and to quantify other parameters in the limit state function of the service life design (e.g. the so-called execution factor k c). The capabilities of two promising methods, spectral analysis of surface waves and spectral analysis of lamb waves, are discussed in combination with bottlenecks that need to be passed.