지반-구조물 상호작용을 고려한 사장교의 내진해석 사례 연구

초록

Purpose: This study quantitatively investigates the influence of soil–structure interaction (SSI) on the seismic response characteristics of bridge structures during seismic design. Method: A cable-stayed bridge was selected as a case study to evaluate these effects through a two-stage analytical approach. In the first stage, site-specific free-field ground motions were obtained using the SHAKE91 program, from which the nonlinear dynamic properties of the subsurface soil were derived. the second stage, SSI analysis was conducted using the substructure method implemented in the SASSI program. Result: Impedance analyses were performed to estimate equivalent spring stiffness values for the pylon foundation, which were then integrated into the structural model. The seismic response results indicated that incorporating SSI effects led to variations in member forces of up to approximately 1% compared to those under fixed-base assumptions. Conclusion: These discrepancies are attributed to the dynamic interaction between the ground and the superstructure. The findings highlight the necessity of considering SSI effects in the seismic analysis and design of critical bridge structures to ensure improved structural reliability and seismic safety.

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