Seismic monitoring bridge decks with rotational friction dampers
Safely and economically seismic energy dissipation is the most important way to deal with devastating effects of the earthquake. Classic seismic retrofitting techniques amortize the energy in the members and with their plasticity. In this way, in addition to compromising the structural members, capacity of structural members for subsequent energy absorption will decrease against the forces that their amounts are not known and the security of structure will also disappear. More appropriate method is the use of dampers that amortize the energy applied to the structure in themselves and maintain the structures. These absorber are offered in two permanent and switching forms. Rotational friction dampers are known as added yield moment of damper (displacement and reducer of base shear of structure). In this study, the properties of rotational friction damper have been examined and its function in the structure of a bridge with a length of 40 meters and four 10-meter spans and a height of 7 meter. 2000SAP software was used to model the structure of bridge and applying the rotational friction damper with Multi-linear plastic elements. After modeling and loading, the elements of damper were modeled in different positions of the structure under time history loading and its analysis through the menu of Link in software and in order to examine the function of installed elements in mentioned structure, modelling was performed in two modes (with and without damper) under time history loading. In order to determine the behavior of rotational friction dampers, various performance indicators such as structural displacement and base shear of structures were used. Firstly, the values of these indicators were extracted from the structures without damper and then, the maximum values of performance indicators were extracted from the structures with damper. These values were compared with each other and reduction in various performance indicators were provided by percentage.