Dept. of Civil Engineering, Islamic Azad University, Science and Research Branch, Tehran, Iran
International Institute of Earthquake Engineering & Seismology (IIEES), Tehran, Iran
School of Railway Engineering., Iran University of Science and Technology, Tehran, Iran
In the conventional design and analysis methods affecting parameters (loads, materials'
strength, etc) are not set as probable variables. Safety factors in the current Codes and
Standards are usually obtained on the basis of judgment and experience, which may be
improper or uneconomical. In technical literature, a method based on nonlinear static analysis
is suggested to set Reliability Index on strength of structural systems. In this paper, a method
based on Nonlinear Dynamic analysis with rising acceleration (or Incremental Dynamic
Analysis) is introduced, the results of which are compared with those of the previous (Static
Pushover Analysis) method and two concepts namely Redundancy Strength and Redundancy
Variations are proposed as an index to these impacts. The Redundancy Variation Factor and
Redundancy Strength Factor indices for reinforced concrete frames with varying number of
bays and stories and different ductility potentials are computed and ultimately, Reliability
Index is determined using these two indices.