Database of structural behavior of reinforced masonry ring-beams

The building structural capacity against horizontal forces can be effectively improved by means of introduction of ring-beams, able to form a box-like container within the volume defined by the walls and to prevent out-of-plane collapse mechanism of a single wall panel. Different types of ring-beams have been proposed in the past to increase the load capacity of historic masonry constructions and box-like structures have previously proven to perform well under seismic action. The most common type of ring-beams is made of steel rebar reinforced concrete (RC). This retrofitting method has been widely used in the last thirty years in many seismic prone areas, but several issues arose during earthquakes for the different mechanical behaviour, mainly in terms of deformation, of the coupled materials (masonry and RC). This paper reports the results of several laboratory and on-site investigations carried out by the authors in the last 10 on masonry-made ring-beams reinforced with composite materials. The aim is to identify a retrofitting method for historic masonry buildings, which, while improving structural capacity against horizontal forces, will not significantly alter the stiffness properties of the building and its structural components and it will meet the requirements imposed by the conservation bodies in terms of reversibility and compatibility with original masonry. The experimental investigation, conducted on two groups of full-scale ring-beams (made of brick and stone masonry) demonstrated that it is possible to assemble reinforced masonry beams. High bending capacities were recorded with limited flexural stiffness.