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Probabilistic Evaluation of Ridge Isolation as an Inventive Method for Mitigating the Displacement of Isolated Buildings under all Possible Hazards

Tavassoli, Sina | 2018

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 51454 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Bakhshi, Ali
  7. Abstract:
  8. The main purpose of this research is to evaluate the probabilistic benefit of the implementation of second isolation layer in isolated structures to both the structure and the constructor. The innovation of this research is in the utilization of a seemingly useless part of the structure, which is the ridge, for mitigating the structure’s displacement. For this purpose, a five-story residential structure and its ridge have been isolated and modeled as an MDOF system with two degree of freedom in MATLAB software and the benefits due to the reduction in displacement and acceleration has been calculated. The results indicate 40 percent reduction in the main structure’s displacement and a benefit which is about 18 percent of construction’s cost. In the next and the main step of this research, in order to consider the randomness in the evaluation, all parameters were considered as a random variable with their own specific distribution and some models were developed for earthquake, wind, and snow in order to accurately predict their behavior and the possibility of their occurrence. And finally, instead of using the codes for assessing the responses, an artificial earthquake was generated and the structure’s responses were evaluated under that record which contained both the randomness and the regional characteristics. The results indicate 35 percent reduction in the main structure’s displacement and an average benefit which is about 11 percent of construction’s cost. It should be mention that the aforementioned digits are the average of the PDF of the gained benefits. Furthermore, with respect to the issue of serviceability, the implementation of the proposed system results in better servicebility since the main structure’s displacements reduced considerably. In this research, the Rt software was used as a platform for producing random variable and introducing them to MATLAB for assessment of responses and generating an artificial record. Finally, as far as the validity of the results is concerned, the time history responses of the structure were calculated under 22 far-field records and 14 near-field records which are the suggested records of FEMA-P 695. The average of the calculated results indicates the validity of both former methods which were a deterministic method and the probabilistic one
  9. Keywords:
  10. Base Isolation ; Tuned Mass Damper (TMD) ; Probabilistic Assessment ; Hazard and Operability Analysis (HAZOP) ; Dual Isolation

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