The Influence of Earthquake Input Excitation Frequency Content on Seismic Response of Slope Topography

Topographic effects significantly influence seismic ground motion, particularly in terms of frequency content and structural response. This study investigates the impact of slope topography on soil-structure-interaction (SSI) and topography-soil-structure-interaction (TSSI) through numerical modeling. A ۱۵° slope and a flat ground condition were simulated using the HSS soil constitutive model under three earthquake records: Loma Prieta, Hector Mine, and Chuetsu-Oki. Response spectra were generated to evaluate changes in predominant periods. Results indicate a fundamental natural period of ۱.۴ s for all three records. In the flat condition (SSI), the dominant periods shifted to ۰.۲ s for Chuetsu-Oki, ۰.۸ s for Hector Mine, and ۰.۴ s for Loma Prieta. These shifts demonstrate the sensitivity of frequency content to input motion and site conditions. Furthermore, the findings suggest that under SSI, mid-rise structures (۲-۸ stories) are most susceptible to damage, whereas under TSSI, even high-rise buildings exceeding ۱۰ stories may be at significant risk. The study highlights the necessity of incorporating topographic effects in seismic design to ensure the safety of structures located on sloping terrains.

کلیدواژه ها:

Slope Topography ، Frequency Content ، Soil-structure-topography interaction ، Input excitation frequency ، Numerical modeling