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Evaluation of energy-based modal pushover analysis in reinforced concrete frames with elevation irregularity

Hashemi, M. J ; Sharif University of Technology | 2010

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  1. Type of Document: Article
  2. Publisher: 2010
  3. Abstract:
  4. In nonlinear static (pushover) methods of analysis as an alternative to time history analysis, the capacity curve of the structure is established with respect to the roof displacement. Disproportionate increases in the roof displacement and even outright reversals of the higher modes can distort the capacity curve of the equivalent single degree of freedom system in these kinds of method, including MPA. To overcome this problem, recently, "Energy-Based" the Modal Pushover Analysis (Energy-Based MPA) method has been introduced. In this method, the absorbed energy and/or the external work in the pushover analysis is considered. Accordingly, the assessment of the Energy-Based MPA method is important in the seismic analysis of asymmetrical and tall buildings. In this paper, the seismic demands of concrete structures with irregularity in elevation are determined, using Energy-Based MPA. For assessment of the presented technique, the results are compared with those from the Non-Linear Time History Analysis (NL-THA). Seven examples including a 2-D simulation of a 12-story building are modeled, using the Opensees Code. For each case, different types of irregularity, such as mass, geometry and variations due to the difference in elevation are considered. Story-drifts and floor-displacements are used as the main parameters for assessment of the results. Based on a study of the structural performance of the models, it has been made clear that different types of the above-mentioned irregularity in elevation do not have any significant effect on the Energy-Based MPA method. Consequently, this method can be considered as an accurate alternative technique for NL-THA, to fairly estimate the seismic demands of structures
  5. Keywords:
  6. Elevation irregularity ; Energy-Based MPA ; Time history analysis ; Absorbed energy ; Capacity curves ; Concrete structures ; External work ; Higher mode ; Main parameters ; Methods of analysis ; Modal pushover analysis ; Non-linear ; Nonlinear statics ; Push-over analysis ; Reinforced concrete frames ; Seismic analysis ; Seismic demands ; Single degree of freedom systems ; Structural performance ; Time history analysis ; Earthquake resistance ; Reinforced concrete ; Roofs ; Seismology ; Tall buildings ; Concrete bridges ; Concrete structure ; Elevation ; Multistorey building ; Seismic data ; Seismic design ; Structural response ; Two-dimensional modeling
  7. Source: Scientia Iranica ; Volume 17, Issue 2 A , 2010 , Pages 96-106 ; 10263098 (ISSN)
  8. URL: http://archive.scientiairanica.com/PDF/Articles/00001255/mofid.pdf