Inauguration UNESCO Chair on Preventive Conservation, Maintenance and Monitoring of Monuments and Sites
Inauguration UNESCO Chair on Preventive Conservation, Maintenance and Monitoring of Monuments and Sites date:24-25 March 2009
2. Hole Drilling Technique for onsite stress measurement has been used to validate the stress level at 2 pillars of the Sint-Jacobschurch (Leuven, B). The technique allows estimating the stress in a stone from measuring deformation when a small hole is made. It is a low intrusive technique. The application of it is limited to local stress measurements and is a complement to stress estimate from calculations of from the use of –for example- flat jacks. In addition to the flat-jack technique, the full 2D stress state is obtained including possible tensile stresses. The low intrusive nature of the test and the fact that the measurement can only be applied once makes the test less feasible for monitoring applications. On site measuring of stress can correct calculations that need to consider levels of uncertainty and are therefore usually overestimating stress. Having correct information can contribute to preventive conservation.