Loading...

Evaluation of Seismic Behavior of Anchored and Unanchored Tanks By Using Endurance Time Method

Alembagheri, Mohammad | 2009

471 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 39914 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Esmaeilpour Estekanchi, Homayun
  7. Abstract:
  8. Endurance Time (ET) method is a relatively general analysis method based on time history analysis for evaluation of structure systems under dynamic excitations resulted from earthquakes. Assessment criterion in this method is based on time of endurance of structure versus applied acceleration function and don't use parameters such as stiffness, lateral strength, period of structure and other dynamic characteristics straightly. Upper time of endurance means better operation. In this method, if assumed damage index stays under allowable limit until determined time of endurance then the structure assumed acceptable. In this study, nonlinear analysis of anchored and unanchored (on rigid base) on-ground tanks be done under actual earthquake records and also developed ET accelerograms that are based on those actual records, for determination of efficiency of ET method in analysis of on-ground tanks. The aim is comparison between average of maximum results of earthquake records and average of maximum results of ET records until target time (10th second) and indicating strength and weakness points of ET method in predicting results of analysis of anchored and unanchored tanks under actual records by a suitable and sensible error percentage. For this purpose, three tanks by various geometric shapes and dynamic parameters, seven actual earthquake records with three increasing ET accelerograms that are produced from those seven actual records are selected. Analysis of these tanks be done with ABAQUS software. Verification of tank models in software environment has been done using simple static relations and conditions also some various papers, and after assurance of correct function of software, main analyses initiated. Since, in tank model there are two dominant period times (Impulsive and Convective), included that difference percentage between average of results of seven earthquake records and average of results of three ET accelerograms is justifiable by attention to difference between corresponding spectrum accelerations in convective and impulsive periods of tanks, also using ET method has a credible function in tank analysis instead of actual records analysis. Also complete comparison is done between results of anchored and unanchored tanks and variation of parameters such as friction coefficient between tank floor and rigid base, elastic material for shell, effect of roof and etc are studied
  9. Keywords:
  10. Endurance Time Method ; Nonlinear Analysis ; On-Ground Tanks ; Acceleration Spectrum

 Digital Object List

 Bookmark

No TOC