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Application of Endurance Time Method in Optimum Seismic Design of Structures Based on Life Cycle Cost

Charkhtab Basim, Mohammad | 2015

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 47779 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Esmaeil Pourestekanchi, Homayun
  7. Abstract:
  8. In recent decades, large economic losses and social impacts following earthquakes and hurricanes have revealed the need for improved design criteria intended to reduce consequences including economic impacts to an acceptable level along with life protection. So, it is tried to express the expected performance of structures as financial and social criteria. Any assessment on earthquake consequences requires estimations of structural responses to seismic excitations. Endurance Time (ET) method as a dynamic procedure requiring reasonably reduced computational effort compared to other common time-history based procedures, is used to estimate the response of the structure in all levels of hazard intensity. In this research applications of this method in estimation and assessment of earthquake consequences and optimum design of structures based on new performance criteria are investigated. First, a new design methodology based on the total value of the structure namely Value Based Design of structures (VBD) using potential advantages of the ET method is introduced. In this approach the concept of value is directly incorporated in design procedure intended to achieve an economical design with lower total cost in its life time. A deterministic approach to calculate the expected life cycle cost of a structure based on ET results is formulated. Reduced computational demand in ET analysis method provides the prerequisites to practical use of single- and multi-objective optimization algorithms in seismic design. In the first step, application of Endurance Time (ET) method in comprehensive assessment of structural performance in the framework of FEMA-P-58 considering uncertainties is investigated. It is proposed to use the ET method as the response assessment tool in this framework and the expected damage costs, injuries, fatalities and probability of collapse are estimated using a Monte Carlo approach to account for uncertainties. Moreover, a practical procedure to estimate the probable seismic losses utilizing reliability methods and the Endurance Time (ET) method is introduced. Using the continuous nature of ET analysis results, first order reliability method (FORM) as a gradient based reliability method is utilized to estimate the annual rate of exceeding any value of loss components. Also, a framework to calculate a quantitative measure of seismic resilience using the ET method is proposed introducing “Resiliency Curve”
  9. Keywords:
  10. Endurance Time Method ; Nonlinear Dynamic Analysis ; Optimization ; Life Cycle Cost (LCC) ; Reliability Analysis ; Performance Based Design ; Monte Carlo Method ; Damage Assessment

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