Abstract:
The integrity of constructed drilled shafts is a presupposition of geotechnical and structural design. An execution complying with relevant standards shall reliably prevent shafts from significant defects with the potential to compromise structural safety.
In special cases additional integrity testing is specified as part of QA/QC. Beside the well-established "cross-hole sonic logging" method, the younger "thermal integrity profiling" is based on the hydration heat response of the bulk concrete. For a serious understanding and assessment of actual testing results, and further to set validated acceptance criteria in the "recommendations on Piling" (by the German Geotechnical Society), practical and theoretical investigations have been performed.
The numerical simulations were part of a master thesis at the University of Applied Sciences where Prof. Stengel is teaching who's an expert in concrete technology. The field studies include testing of a pile with artifical soil inclusions. The numerical simulations show not only the influence of variations in the concrete mix, in size and location of anomalies but also of the boundary conditions.
Thanks to the Federal Water Engineering and Research Institute in Germany (BAW), BAUER could do practical TIP and CSL tests at shafts with pre-installd artificial sand inclusions, in- and outside of the reinforcement cages.