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Performance Based Assessment of Steel Frames With Cartridge Dampers Using Endurance Time Method

Nikfar, Farzad | 2010

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 41274 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Esmaeil Pourestekanchi, Homayun
  7. Abstract:
  8. In recent decades, most of the codes have placed a high value on Performance Based Design of structures; however, these methods are computationally complex and time-consuming, and caused researchers to seek new and efficient methods to investigate performance of structures under different intensities of seismic loading. This issue is much more obvious when optimum design of structures, which requires repetitive analysis, is investigated. This investigation tries to provide better insights into the dynamic behavior of structures in continuous performance levels. As a first step, this research aims at analytical investigation of new type of metallic damper called Cartridge Damper, and in the second step, it proposes the verified method to find the optimum outline of metallic dampers in steel frames using Endurance Time Method along with optimization methods (both Genetic and F-min-search algorithm in this project), and in the last step, the effect of metallic damper’s parameters on performance of structures investigated. Endurance Time Method consists of excitation of a structure through increasing accelerograms which their different endurances indicate various intensities of earthquakes in different hazard levels. Endurance Time Method significantly decreases amount of computation in each step; consequently, various optimization methods can be employed to define design parameters. According to this, various inelastic moment-resisting steel frames, which possess some flaws in primary designing phase, are modeled using OpenSees. Furthermore, genetic algorithm is employed to define the optimum outline of dampers throughout the structure in a way that the structure reaches the allowable performance at the lowest cost. In addition, the performance of the structure under seismic excitation in different performance levels is evaluated based on interstory drift ratios before and after rehabilitation. In all cases, the improved structure has an acceptable performance during seismic loading, and Endurance Time accelerogram leads to an almost proper prediction of structure behavior at various earthquake records. In this research, ASCE-41 is used as the performance base design criterion
  9. Keywords:
  10. Optimization ; Genetic Algorithm ; Performance Based Design ; Endurance Time Method ; Cartridge Metalic Damper

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