Exploitable results Optimization of energy dissipation devices, rolling systems and hydraulic couplers for reducing seismic risk to structures and industrial facilities; REEDS The REEDS Project concerned the development of anti-seismic devices which could offer protection to structures superior to that obtained with traditional methods relying on the post-elastic behaviour of the structure itself. The devices included in the project were: - dampers (viscoelastic (VED), elastoplastic (EPD), viscous dampers (VD), shape memory alloy), - hydraulic couplers (HC) - shock transmitters and - rolling-ball rubber layer (RBRL) isolators. Viscoelastic dampers Using the developed compound, two types of device were designed and prototypes manufactured and tested: a rectangular shaped device for incorporation into structural frames and an annular device for pipeline bends. The performance of the rectangular devices was assessed by the pseudo dynamic (PsD) testing of a reinforced concrete frame mock-up, two-storeys of part of a reinforced concrete office building scaled by ? in dimension. The level of the earthquake was equivalent to 0.3g PGA for the full-size building. The peak displacement of the second storey with the devices installed was only observed to be about 20% of that without the devices. The installation of VEDs thus successfully transformed the non-seismic design RC frame to one able to restrict the response to the design level earthquake to elastic deformations. Elastoplastic dampers The aim was to develop a damper based on a torsional geometry. Compared with the conventional bending deformation, torsion allows higher energy dissipation, a longer low cycle fatigue life and a simpler, more cost effective design. Testing of prototypes showed that a circular cross-section gave more stable force-deformation properties than square cross-section, the devices gave up to 70% dissipation and at the design displacement the devices withstood over 60 cycles before failure. Viscous dampers and hydraulic couplers The effectiveness of dampers in reducing seismically-induced longitudinal deck displacements and internal forces within the towers of a cable-stayed bridge (the Arade river bridge, Portimao, Portugal) was assessed by numerical analysis. Both elastoplastic and viscous dampers were effective in markedly reducing the deck displacement. For either elastoplastic or viscous dampers giving a maximum force of only 2.5 to 5% of the deck weight, it is possible to reduce the deck displacement by about 65%. Rolling-ball rubber layer isolator The rubber layer provides damping to the system to control the magnitude of the horizontal displacement. Prototype devices were developed, manufactured and tested. The devices were evaluated in shaking-table tests of a mock-up of one bay of a gas-insulated sub-station. Comparison of the horizontal accelerations at the top of the mock-up for fixed-base and base-isolated conditions showed the isolators to reduce the responses by 60%. The potential of the RBRL isolators to upgrade the seismic resistance of an existing GIS design is thus confirmed. In addition to the development of improved device, the project aimed to evaluate their performance in seismically vulnerable structures either through experimental tests, numerical evaluation or a combination of the two. Searching for OpenAIRE data... There was an error trying to search data from OpenAIRE No results available
