Seismic design coefficients verification of regular and vertically irregular high-rise shear wall buildings using bidirectional horizontal ground motions and 3D modeling

Recommended seismic design coefficients in design codes were based on previous research primarily on regular low- to medium-rise building configurations using two-dimensional analysis. Thus, the present study addresses these limitations by validating these design coefficients for high-rise buildings, considering different heights, structural systems, and irregularities using three-dimensional (3D) dynamic response simulation and bidirectional earthquake records. Nine high-rise reinforced concrete structures of 40 to 60 stories are designed in detail to ensure optimized design, detailing, and fair assessment of code-recommended coefficients. The design coefficients are verified using 3D fiber-based simulation models, inelastic pushover analyses, and multi-record bidirectional incremental dynamic analyses considering a diverse set of 26 earthquake records. The observed overstrength factors for regular and irregular buildings range between 2.62 and 2.98, reflecting the code conservative value of 2.5. The deflection amplification coefficients (C_d) exhibit a 14 % to 25 % safety margin and validate the design code approach for assigning equal or lower C_d factors than the response modification coefficients (R). The safety margins for the R coefficients ranged from 42 % to 63 % for the bearing wall buildings and between 7 % to 21 % for dual structures. The current study suggests the potential for increasing the code-recommended R coefficients, resulting in more cost-effective designs for regular and irregular high-rise buildings without compromising safety.