Adequate seismic separation distance between adjacent buildings is essential to prevent seismic pounding, which remains one of the most critical sources of damage in densely constructed urban areas. Many codes, including the Egyptian Code for Loads ECP 201, rely on simplified displacement-based formulas that may not fully capture the complex dynamic interaction between neighboring structures. This study evaluates the adequacy of seismic separation distances prescribed by ECP 201 by benchmarking them against detailed nonlinear time history analysis (NLTHA). Three reinforced concrete moment-resisting frame buildings—5, 8, and 11 stories—were modeled in CSI ETABS using realistic material nonlinearities, geometric nonlinearity, and bidirectional seismic excitation. Three horizontal ground motion records were selected and amplitude-scaled to ensure spectral compatibility. The NLTHA results revealed that the required separation distances were consistently larger than those calculated using ECP 201, by approximately 20% to over 100% in some configurations. The findings indicate that actual seismic demand is strongly influenced by dynamic interaction and characteristics of the applied ground motions. The results indicate that the simplified code expressions may benefit from supplementary evaluation procedures, particularly for mid-rise RC buildings in dense urban environments |
