EXPERIMENTAL AND NUMERICA DETERMINATION OF THE AXIAL LOAD IN STRUCTURAL TIE-RODS WITH COMPLEX BOUNDARY CONDITIONS

Monitoring of the in-exercise axial load in structural tie-rods is more often necessary in order to monitor the health of a part or of an entire ancient building. In recent works we proposed a non-invasive method devoted to the estimation of the axial load in these slender elements that is based on the measure of the vibrational behavior and the comparison of natural frequencies with a numerical model. In this work we add to this method a complementary set of parameters to take into account non-conventional boundary conditions at the extremities of the tie-rods that usually occur in real cases, i.e. an elastic bed at the rod/wall interface. In comparison with fixed-end or pinned conditions, the elastic bed condition better approximates the experimental behavior and, many cases, make the estimation more conservative.