Recent earthquakes have highlighted the high seismic vulnerability of the structures and the need of retrofitting interventions. Different seismic protection strategies and techniques can be used to increase the seismic capacity of existing masonry constructions. Common retrofitting techniques are generally based on a strengthening approach. Instead, innovative retrofitting strategies can be used to mitigate the effect of earthquakes, with the aim of decreasing the seismic demand on the structure or increasing its energy dissipation capacity. One of the most innovative devices is the Unbonded Fiber Reinforced Elstomeric Isoletors. UFREIs are made of alternate layers of fiber and rubber and they are interposed between the ground and the foundation, with the particularity that no bonding or fastening is provided between the bearing and top-bottom supports. In this paper, through the FE software code Abaqus, a series of nonlinear dynamic analysis are performed to investigate the influence of crosslinking on the seismic performance of UFREI made of regenerated rubber. Numerical results show that the devices vulcanized at 130°C for 40 minutes, although having suboptimal crosslinking density, are suitable to properly isolate low-rise buildings.

The building is a masterpiece of the industrial architecture in the thirties of XX century. The original design is the work of the architect Rudolf Fischer. The construction of the building is realized in the period 1924-1925. The combination of different construction materials: masonry, reinforced concrete and timber, gives a unique structure. This contribution introduces a structural investigation, using MFE software, into the stability and efficiency of the design of the roof truss of the storage heritage building in Kustendil. A two dimensional model was used in numerical analysis to discuss and highlight structural sense of Austrian architect R. Fischer in the period of . The modeling of timber construction and the final conclusions are basic for the decision concerning the possible interventions in the building and the possibility to extend the service life of the roof structure.

Losses and damages induced by strong earthquakes are a dramatic reality worldwide. As a consequence, the implementation of innovative protection strategies for both existing and new constructions is of key societal importance. Elastomeric isolators are special devices for seismic isolation of structures. Typically, they are made of alternate layers of steel or fiber reinforced laminas and rubber and they are interposed between the ground and the foundation in order to increase the natural period of the structure and reduce the inertia forces to apply in case of an earthquake. This study proposes a detailed 3D FE modelling of isolators conceived for low-rise masonry buildings in developing countries, carried out through the FE software code Abaqus. The isolator under study consists of an energy dissipation core made by relatively High Damping Rubber and an external EPDM ring. In addition, in order to reduce the production cost and allow its applicability in developing countries, it presents unbonded boundary conditions. In fact, the upper and lower edges do not exhibit any bond with the supports. The main feature of such a device is the large deformability thanks to the rollover deformation and the favorably lower lateral stiffness compared to the bonded isolator.

In recent years the concept of recycling and reuse is a popular issue faced in many fields. During manufacturing processes a huge amount of materials is recovered to minimize waste. In particular, this study investigates the possibility of reuse materials recovered during the production of rubber in standard industrial practice, for the realization of low-cost rubber compounds for fiber-reinforced elastomeric isolators. To cope with this task, a new composition is developed basing on the past experience of the research group and in particular with reference to a previous study by A. B. Habieb et al, where a part of virgin rubber was replaced by regenerated one. Subsequently, a comparison between the two compositions in terms of rheometer curves, uniaxial tensile curves, hardness and compression sets, before and after the process of aging is provided. It is found that the new composition exhibits attractive performances with economic advantages and environmental benefits.