1st Croatian Conference on Earthquake Engineering 1CroCEE 2021

Seismic isolation and energy dissipation devices have been widely used in Italy since the seventies of the past century for the seismic protection of different structures, pioneered by applications on bridges and viaducts. At the end of the eighties, Italy was world leader for the number of bridges and viaducts protected with antiseismic devices. Since then, Italian antiseismic devices have been applied all over the world, from all European seismic-prone countries to South America and Asia.
Over the years, together with the development of new antiseismic devices and the increase in the number of their applications, in Europe there was a continuous development in guidelines and codes culminating in the Eurocode EN 1998, as well as the European Standard on antiseismic devices EN 15129:2009, that are a reference for many non-European countries. The most recent trend of seismic isolation foresees the use of pendulum isolators, alone or combined with fluid viscous dampers, in bridges as well as in other structures (buildings, tanks, etc.). The paper describes some examples of seismic isolation of bridges and viaducts. In particular it focuses on the Saina Ryskulova Bridge in Almaty, Kazakhstan, a curved concrete viaduct divided in 3 sections, made of 11 spans supported by 10 piers plus the abutments. The seismic isolation system includes double concave curved surface sliders (also known as pendulum isolators) and non-linear fluid viscous dampers, the latter allow to increase the energy dissipation of the seismic isolation system and consequently to significantly reduce the horizontal displacements, otherwise too high due to the high seismicity of the area characterised by a PGA of 0.4 g.