Pull-Out Tests of Steel Anchors and Spikes Installed to Solid Brick Masonry Walls
摘要
The bond behaviour of anchors applied to masonry substrates is an important aspect to investigate, especially in case of buildings subjected to seismic actions. This topic has received a growing attention in the last decades, given the various applications that anchors can have in the strengthening of historical structures, such as connection of wall corners, anchorage of externally applied reinforcements or structural elements, stitching of masonry leaves, and others. This experimental research presents and discusses the outcomes of pull-out tests carried out on steel anchors installed on a three-wythe solid brick masonry wall, and having an embedment length of 300 mm. Two types of steel anchors, either solid threaded bars (with M10 and M14 diameters) or spikes made of 24 thin ultra-high strength steel cords, were considered. Moreover, two different embedding matrices were used: a Natural Hydraulic Lime (NHL) based mortar with a nominal strength class of M15, and a bicomponent structural epoxy adhesive. Six different types of installed anchors were tested, since M10 bars, M14 bars and 24-strand spikes were embedded with either the NHL based mortar or the epoxy adhesive. Each set envisaged 3 repetitions, for overall 18 tests. The experimentation extends a previous campaign that investigated the performance of steel cord spikes applied to existing clay brick masonry. The outcomes confirmed the boding efficiency of epoxy adhesives and also highlighted interesting outcomes when using a Natural Hydraulic Lime (NHL) based mortar as embedding material.