The Effect of using Additional Isolated Upper Floor on the Performance Point of R.C. Frame Structures in Armenia

Document Type : Original Article


1 Earthquake Engineering Research Consultant, Yerevan, Armenia

2 Earthquake Engineer, Head of North-East branch of BHRC, Mashhad, Iran

3 Senior Structural Designer, E.S.S. Consulting Eng. Co., Tehran, Iran


Widely distributed 111 series, 10 story R.C. frame buildings are constructed during former soviet union in Armenia and Nagorno-Karabakh province. In current research we illustrate the concept of seismic upgrading of above mentioned buildings, using an Additional Isolated Upper Floor (AIUF). For this purpose, a three dimensional of 111-c R.C. frame building is modeled and analyzed according to Armenian SNIP II-6.02 code, based on 3 soil categories of Rock (Vs>800m/s), Dense Soil (500<Vs<800m/s) and Loose Soil (150<Vs<500m/s) respectively and spectral acceleration level of Sa=0.40g. Later, the AIUF which behaves as a Tuned Mass Damper is added to the model and after tuning for the frequency and damping ratios, Modal Pushover Analysis is carried out on both preliminary and secondary structural models. Finally by the means of FEMA356 guideline, Capacity Spectrum and Performance Point characteristics due to related soil categories are computed for each model, using Armenian SNIP II-6.02 pseudo-acceleration spectrums. The final analysis results show a constant base shear forces with variable displacements during soil degradation, when using Additional Isolated Upper Floor.


[1]-Bungale S. Taranath, 2005, Wind and Earthquake Resistant Buildings, John A. Martin & Associates, Inc. Los Angeles, California.
[2]-Chang, J. CH., Soong, T., 1980, Structural control using active tuned mass dampers, Journal of Engineering Mechanic Divisions, ASCE, 106 (EM6):1091-1098.
[3]- Chopra A. K., 2012, Dynamics of Structures: Theory and applications to Earthquake Engineering (4thed.), Prentice Hall, Englewood Cliffs.
[4]- CSI Perform-3D, 2012, Nonlinear Analysis and Performance Assessment of 3D Structures, Computers and Structures Inc., Berkeley, California.
[5]- Franklin. Y. Cheng, Hongping Jiang, Kongyu lou, 2008, Smart Structures, Innovative Systems for Seismic Response Control, CRC Press, Taylor & Francis group, LLC, N.Y.
[6]- Nassar, A. A., and Krawinkler. H., 1991, Seismic Demands for SDOF & MDOF Systems, John A. Blume Earthquake Engineering Center, Report No. 95. Department of Civil Engineering, Stanford University.
[7]- SNIP II-6.02, 2006, Armenian Code of Practice for Seismic Resistant Design of Buildings,Report No.24 of Ministry of Urban Planning, Yerevan, Republic of Armenia.