seismic retrofit of a typical highway bridge in tehran using fluid viscous dampers

More than 600 bridges have been constructed in tehran in three last decades, and studies of tehran municipality have shown many highway bridges do not have enough resiliency in a severe ground motion. the reports of past earthquakes have revealed that excessive lateral displacement of bridge piers is one of the most important causes of bridge vulnerabilityespecially at fully operational and operational performance level. during the last two decades, passive energy dissipation technologies have undergone great development, finding manyapplications in both new and old conventional bridges. fluid viscous damper (fvd) is one of the most effective devices used in seismic retrofit projects of highway bridges in recent years all around the world especially in japan and united states. fvd devices are designed to be installed at the deck-pier interface in all expansion piers and abutments. this technology has proven very helpful, particularly in retrofit applications where it is difficult to change service load staticconfigurations and when there is a requirement for additional damping.