EXPERIMENTAL INVESTIGATION ON POST-INSTALLED METAL ANCHORS SUBJECTED TO SEISMIC LOADING IN R/C MEMBERS

The paper presents the results of an experimental investigation on the behavior of post-installed expansion metal anchors fastened to R/C pre-cracked columns and subjected to transverse reverse loading. Post-installed anchors in reinforced concrete are of crucial importance for the mechanical resistance and stability of both structural and non-structural members, like facade panels and balconies, both connected to the slabs. In seismic regions, fasteners are expected to transfer cyclic actions as reliably as possible, from the member in question to the concrete. The anchors behavior, however, is still not completely understood in seismic conditions, even if a number of scientific contributions have been lately devoted to this issue, that requires also the definition of appropriate experimental techniques to certify the mechanical properties of the anchors. The aim of this research project is to investigate the behavior of mechanical anchors, by performing a few pull-out tests on anchors installed in pre-cracked R/C columns. The anchors were installed along the cracks, and the effect of crack opening-closing could be studied. In fact, the increasing damage in the concrete and in the anchor, because of the closing-opening process in the cracks, plays a decisive role in impairing the residual pull-out capacity of the anchors.