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

Shorouk M. Elsadany, M. N. Fayed, Tamer M. Sorour, A. M. Anwar, Nasr E. Nasr


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

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Irregular RC Buildings; Elevation Irregularity; Plan Irregularity; Nonlinear Static Pushover Analysis; Response Reduction Factor; Soil Structure Interaction.


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DOI: 10.28991/CEJ-2024-010-03-07


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