parametric study of concrete base isolated buildings in the near-field earthquakes

Recently the experience of recent near source earthquakes such as Northridge, Kobe and Tabas earthquakes have shown that the structures are more vulnerable in the near source earthquakes. This has also shown in many studies. The main reason for that is due to a strong and long period velocity pulse which generates in the near-field (NF) earthquakes. Base isolation systems are one of the methods for reducing the damage and vulnerable in the near source earthquakes, seismic isolation system increase period of vibration which reduce seismic force and the amount of energy transferred into the structure. In this paper, a parametric study has been carried out to study the behavior of based isolated concrete buildings in the near source earthquakes. One base isolated concrete building with 6 stories is considered. The behavior of selected structure has been studied using nonlinear dynamic analysis under three near and three far field (FF) earthquake recorders. A parametric study of various value of stiffness for the base isolation has been studied as well. The results have shown that the responses of building in the NF are very much than FF earthquakes, and the use of base isolation system reduces the base shear and story acceleration of building in NF in contrast FF, but displacement increased. Also the parametric study on the stiffness of base isolation showed that, decreasing stiffness of isolator's causes the base shear and story acceleration reduced, but this subject for story displacements is not valid

کلیدواژه ها:

Base isolation ، Near-source earthquakes ، Seismic behavior ، Concrete buildings