Loading...

Improvement of Nonlinear Static Analysis Procedures to Incorporate the Effects of Near Field Strong Ground Motions

Shodja, Amir Hossein | 2013

579 Viewed
  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 44646 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Rahimzadeh Rofooei, Fayaz
  7. Abstract:
  8. Drift spectrum has recently been introduced as a new measure for estimating the inter-story drift demands in buildings under near field ground motions. This new spectrum is developed using a uniform-stiffness continuous beam model. Practical limitations in the procedures based on such beam models have caused structural engineers to pay little attention to drift spectra. This thesis uses a lumped mass, non-uniform beam model to calculate the linearly elastic and also nonlinear drift spectra. The proposed method is simple and can overcome many deficiencies of the previously introduced models. In contrast to the other available methods, it can take into account the very important effect of height-wise stiffness reduction on drift demands, without any assumption on the relationship between the height and the fundamental period of structures, or numerical difficulties in computing the drift spectra. Drift spectra for low, medium, and high-rise buildings are computed using near-field strong ground motions. The effects of the type of structural system, ratio of the lateral stiffness of top story to that of first story, the height-wise variation of structural stiffness, the number of stories, higher modes, the damping ratio, the ductility ratio, and the post-yielding stiffness ratio on inter-story drift demands are investigated. At this study by considering the period elongation due to nonlinear behavior of structural models and the increase in the equivalent damping ratio of the system caused by hysteretic behavior of the structural models, a method is proposed to calculate substitute structure and the accuracy of the methods is verified using a number of SAC building models. A method is presented for using these spectra in estimating the nonlinear drift demands in moment resisting frame structures and also a modification in pushover analysis is proposed
  9. Keywords:
  10. Substitute Structure ; Drift Spectrum ; Apparent Stiffness ; Near-Field Earthquake ; Pushover Analysis ; Nonlinear Time History Analysis

 Digital Object List

 Bookmark

No TOC