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Investigating the Performance of Multiple Tuned Mass Dampers on the Long Span Cable Stayed Bridge Under Multiple Support Excitation
, M.Sc. Thesis Sharif University of Technology ; Rahimzadeh Rofooei, Fayyaz (Supervisor)
Abstract
Cable stayed bridge are characterized by a long fundamental period, large flexibility, lightweight and low structural damping, which is vulnerable to large amplitude oscillations when excited by earthquake. So, it is important to study the seismic behavior of cable-stayed bridges. Spatial variation of seismic ground motions denotes the differences in amplitude and phase of seismic motions recorded over extended areas. The result of past analyzes indicate that the effect of the spatial variation on the response of bridges can be detrimental. On the other hand, tuned mass dampers (TMDs) or vibration absorbers are small mass-spring-dashpot units calibrated to be in resonance with a particular...
Seismic Response of “Karroon III” DAM to Non-Uniform Ground Motions
, M.Sc. Thesis Sharif University of Technology ; Ghaemian, Mohsen (Supervisor)
Abstract
Usually in analysis of arch dams, applied seismic motions on dam-foundation interface are assumed to be uniform. This is while that recorded motions show non-uniform accelerations in dam-foundation interface. Analyzing of the dam under this non-uniform accelerations we can find the importance of this assumption in analysis of arch dams. Two earthquakes were excited “KAROON III” dam at 20.11.2007 and 21.11.2007. The respective motions were recorded by the array of accelerometers that has been installed on the dam. The recorded motions, indicated non-uniformity of excitations in accelerometers were installed near the dam-foundation interface. Therefore this data provided an opportunity to...
Seismic responses of arch dams due to non-uniform ground motions
, Article Scientia Iranica ; Volume 19, Issue 6 , December , 2012 , Pages 1431-1436 ; 10263098 (ISSN) ; Sohrabi Gilani, M ; Sharif University of Technology
2012
Abstract
In the present paper, spatially variation input effects on seismic responses of arch dams have been studied. Recorded ground accelerations at the dam foundation interface of Pacoima dam during January 13, 2001 were used for the purpose of this investigation. A numerical finite element model was developed for dynamic analysis of the dam reservoir system. The modified version of NSAD-DRI finite element program was used for the analysis and the ground acceleration time histories were interpolated at all dam foundation interface nodal points. Total and pseudo static displacements as well as developed stresses due to uniform and non uniform excitations are obtained. The results reveal that...
Application of Existing Damage Detection Measures for Long-Span Cable Stayed Bridges under Multiple Support Excitations
, M.Sc. Thesis Sharif University of Technology ; Rahimzadeh Rofooei, Fayyaz (Supervisor)
Abstract
Damage and collapse in structural systems due to unexpected structural loading that seems to be inevitable sometimes leads to financial and human losses, despite of all safety measures considered for the system. Therefore, using structural health monitoring methods in order to estimate structural damages and preventing structural collapse, have drawn a lot of attention. In this study, the performance of different system identification methods such as mode shape curvature method, energy method, etc., to extract the dynamic properties of a cable-stayed bridge is examined. One of the main features of this study is to consider the seismic response of the bridge under multiple support excitations...
Spatial variation input effects on seismic response of arch dams
, Article Scientia Iranica ; Volume 19, Issue 4 , August , 2012 , Pages 997-1004 ; 10263098 (ISSN) ; Ghaemian, M
Elsevier
2012
Abstract
In the present paper, the seismic response of an arch dam subjected to spatial variation of ground motions along the interface with its foundations is investigated. Recorded ground accelerations at the dam foundation interface of an arch dam were used for the purpose of this investigation. Topographic amplification between various points of the interface was studied by obtaining ratios of the response spectral displacement and spectral pseudo acceleration. Time shift and amplification between stations show the nonuniform nature of ground motions for large structures like dams. Recorded ground accelerations were interpolated for different nodes of the finite element model. The seismic...