Behavior of RC buildings with column discontinuity under the influence of vertical acceleration and near-fault effects

This study investigates vertical irregularities in structures with column discontinuities, a topic rarely examined in existing literature. The critical importance of this issue was highlighted by the Kahramanmaraş earthquakes, which exceeded expected maximum acceleration values in both horizontal and vertical components. In response, 80 Nonlinear Time History Analyses (NLTHAs) were conducted using acceleration records for ZD-type soil, considering near-fault effects (Mw>=7.0). Scenarios were analyzed both with and without vertical acceleration to assess the behavior of regular and irregular structures under design-level (DD2) and maximum-level (DD1) earthquakes. The results indicate significant changes in axial load-carrying capacity, especially in irregular structures, due to vertical accelerations. Notably, while using average responses from multiple earthquake records is a common practice, this approach may overlook critical structural vulnerabilities. Peak responses revealed that columns might be insufficiently designed if only average values are considered. Therefore, the study emphasizes the necessity of evaluating the variability in structural responses across different seismic scenarios rather than relying solely on average earthquake effects. This comprehensive approach ensures more accurate assessments of structural resilience, particularly for irregular structures subject to near-fault influences.