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Application of Shape Memory Alloys (SMA) in Re-Centering the Base-Isolated Steel Structures under Near Field Earthquake Excitation
Ahmadnejhad, Mahmoud | 2015
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- Type of Document: M.Sc. Thesis
- Language: English
- Document No: 48329 (53)
- University: Sharif University of Technology, International Campus, Kish Island
- Department: Science and Engineering
- Advisor(s): Rahimzadeh Rofooei, Fayaz; Jahanshahi, Mohsen
- Abstract:
- Base isolation system is an efficient passive structural control approach to save the structures from the harms of earthquakes. The base isolated systems help to reduce the base shear by increasing the period of the structures, as well as dissipating the seismic input energy by its inherent damping mechanism [1]. However, the residual displacement of the base isolation systems resulted from strong ground motions would remain as a main obstacle in its regular serviceability after the main event. In that regard different isolating devices have been introduced to resolve the problem of the remaining permanent displacement. On the other hand, Shape Memory Alloys (SMAs) are among the newly introduced smart materials that could undergo large nonlinear deformation with considerable dissipation of energy without leaving any permanent displacement afterwards. Not surprisingly, SMAs have found a variety of applications in different areas of structural engineering.To save structure from the hazard of high risk earthquake excitations with performance preservation a semi- active base isolated system with shape memory alloy (SMA) is a recommended solution. The semi-active base isolated system combines a laminated rubber bearing with shape memory alloy [2]. The smart isolation system is compared to laminated rubber bearing isolation systems, to exhibit the capability of this approach. The semi-active isolated system takes advantage of the shape memory alloy (SMA) at different levels of strain to reduce the residual displacements of the laminated rubber bearing. The hysteresis of the shape memory alloy (SMA) is used to increase the energy dissipation [3]. The optimal application of SMAs with the base isolation system could minimize the residual bearing displacement efficiently [4].
In this study, the feasibility of smart isolation system, i.e., the combination of traditional LRB with the SMAs in reducing the response of the base isolated structures under near field earthquake records will be examined. Also, a new configuration of SMAs in conjunction with LRB will be considered that is easier to operate as well as its maintenance - Keywords:
- Base Isolation ; Shape Memory Alloy ; Near-Field Earthquake ; Nonlinear Seismic Analysis ; Dynamic Analysis
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