Anwendung einer geo-elektrischen Untersuchungsmethode für Mauerwerk im Rahmen eines Instandsetzungsvorhabens / Geo-Electrical Survey of Masonry for Restoration Projects

Geo-electrical relative difference mapping is presented as a non-destructive evaluation technique for ancient masonry. The method allows to visualise the internal structure and condition of the masonry. The decision on the necessity and on the type and degree of consolidation or strengthening of the masonry wall can be based on the information, obtained from the mapping. The paper deals with the arrangement of the original measurements to make them suitable for engineering evaluation. Firstly a numerical model is presented to filter out the influence of geometrical boundary conditions: they distort the measurements, but are of no interest for the evaluation. Secondly the maps are calibrated, to eliminate the influence of measuring configuration, and moisture content. The calibration methods are presented, and applied on the resistivity measurements, executed at the restoration project of the building "Duke's Mills" (13th Century) at Aarschot (B).