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Application of Endurance Time Method in Seismic Analysis of Bridges

Ghaffari, Esmaeil | 2010

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 41069 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Esmaeil Pourestekanchi, Homayun
  7. Abstract:
  8. In this research the appilication of a new method named Endurance Time (ET) analysis in seismic analysis of multi span bridges in linear and nonlinear ranges is investigated. Endurance Time is a time history based method of seismic analysis. In this method structure is subjected to an intensifying predefined acceleration function and different damage indices of the structure are evaluated through analysis time. The Endurance Time criterion and the Endurance Time acceleration functions have been generated in previous researchs of ET group. Using 7 earthquake records which are selected from hundred ones of PEER database based on FEMA p695 recommendations, several scaling methods are used to match the earthquakes with the target response spectrum. The target response spectrum is related to Berkeley (zipcode: 94704) and is selected from FHWA 2006 which is similar to the one of AASHTO seismic specifications 2009. These records are used for the comparison of the results of Endurance Time analysis and current seismic analysis methods. To compare the results of Endurance Time analysis with nonlinear time history analysis, the suitable series of acceleration functions should be selected, because each series of ET acceleration functions is generated based on a specific target response spectrum. Selected from a PEER report, 6 bridge models are used in this research. All possible seismic analysis methods including equivalent static load, response spectrum, pushover and time history in both linear and nonlinear ranges are done and the results are compared to Endurance Time analysis results for two sets of ET acceleration functions. A comprehensive statistical study on the accuracy of Endurance Time analysis results and their dispersion is also done. Based on the results, advantages and disadvantages of this method are described. Results of Endurance Time analysis for bridge models are compatible with the results obtained from nonlinear time history analysis and this compatibility is in advance for linear range. Based on time needed for Endurance Time analysis, ET is more economical than time history and also more reliable than response spectrum analysis in predicting the distribution of engineering demand parameters in the structures
  9. Keywords:
  10. Seismic Analysis ; Time History Analysis ; Bridges ; Endurance Time Method

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