SHAPE MEMORY ALLOYS SEISMIC DEVICES AND EUROPEAN PATENT EP 11008881.2 (BIM-28)
During an earthquake bridge thrusting structures (arches or vaults) and decks are subject to movements and accelerations which cause differential damage that can lead to both structures collapse.
Shape memory alloys have a unique property, known as super-elasticity (or pseudoelasticity) that dissipates large amounts of deformation energy through hysteretic cycles in the stress-strain plane. The result of such cycles is a zero or almost zero residual deformation, which can be helpful during seismic events to ensure deformation energy dissipation ensuring the repositioning of elements in the pre-earthquake configuration.
CETMA is able to design and apply bridge restraint and SMA-based devices for protection of both pushing structures and bridge decks. It owns also the European Patent EP 11008881.2.
The device for thrusting structures is designed to be installed in series with traditional metal chains that are normally used to reinforce thrusting structures absorbing horizontal thrust. The device can be designed, depending on intervention area, both to counteract resulting action of earthquake both thermal expansion of metal chains that vary a lot forces balance in the structure.
The know-how regards the various damping properties of different alloys such as Nitinol (NiTi) and other copper-based (NiTiCu).
The technology can be applied to infrastructure sector, for protection in case of an earthquake, and to cultural heritage sector (thrusting masonry structures) or for existing buildings protection.