Response Reduction Factor for Structures with Significant Irregularities on Different Soil Stratum

Shorouk M. Elsadany (Teaching Assistant of Structural Engineering, 6 October University, Cairo,)
M. N. Fayed (Structural Engineering Department, Ain Sham University, Cairo 11757,)
Tamer M. Sorour (Structural Engineering Department, Ain Sham University, Cairo 11757,)
A. M. Anwar (Head of Hydraulic Structures Department, National Water Research Center,)
Nasr E. Nasr (1) Teaching Assistant of Structural Engineering, 6 October University, Cairo, Egypt. 2) Structural Engineering Department, Ain Sham University, Cairo 11757,)

Civil Engineering Journal
Vol 10, No 3 (2024): March

The ability of a structure to dissipate energy through inelastic behavior is reflected in the response reduction factor (R), which is influenced by redundancy, ductility, and overstrength. Accurate determination of R is crucial for seismic design. This study focuses on determining the response factor for reinforced concrete (RC) structures with various irregularities. Non-linear static pushover analysis using SAP2000 was employed for numerical simulations to assess the impact of soil-structure interaction (SSI). The analysis included elevational and in-plan irregularities, revealing that buildings with irregular vertical geometries have lower inelastic seismic capacities compared to regular buildings. Consequently, R should be reduced by 15–40% from the ECP 2020 standard before the design phase for such structures. Irregularity was found to have a significant impact on weak soil conditions (C), leading to a reduction in R of 20.3% and 13.1% for fixed and isolated supports, respectively, on loose soil. Additionally, stiffer base soils were associated with higher R values for the same structure. Doi: 10.28991/CEJ-2024-010-03-07 Full Text: PDF