In the heart of South Korea, where apartment complexes with sprawling underground parking are as common as kimchi, a groundbreaking study is challenging traditional seismic design methods. Led by Jin-Sun Lee, a professor at Wonkwang University, the research delves into the soil-structure interaction (SSI) of these unique buildings, potentially reshaping how we approach seismic design in the future.
Imagine an apartment complex with multiple levels of underground parking, stretching out like an iceberg beneath the surface. Traditional seismic design methods treat the foundation as a rigid, massless base, but what happens when the foundation is vast and deep, like those in Korean apartment complexes? This is the question that has been bugging Lee and his team.
“When you have extended underground parking, the building’s response to earthquakes changes,” Lee explains. “The conventional methods might not cut it anymore.”
To tackle this, Lee and his team employed a direct approach involving a three-dimensional non-linear response history analysis. They modeled the underground floor using shell elements, accounting for kinematic interaction, as well as both the inertial and back-stay effects. In simpler terms, they considered how the soil and the structure move together, how the mass of the underground floors affects the building, and how the underground floors support the upper structure.
The results were eye-opening. While kinematic interaction—how the soil and structure move together—remains valid beyond the limitations set by the current standards, the inertial interaction of underground floors must be addressed when their size and embedment depth exceed these limitations. This means that the mass and movement of the underground floors can significantly impact the building’s response to earthquakes.
So, what does this mean for the future of seismic design? For one, it could lead to more accurate and safer designs for buildings with extended underground parking. But it also opens up a broader discussion about the limitations of current seismic design standards. As Lee puts it, “Our findings suggest that we might need to revisit and possibly revise the current standards to better account for these unique structures.”
The implications are significant, especially for countries with frequent seismic activity. Buildings with extended underground parking are not unique to Korea, and this research could influence seismic design practices worldwide. Moreover, as urbanization continues to drive the demand for such structures, this research could shape the future of urban planning and construction.
The study, published in the Journal of Asian Architecture and Building Engineering, translated to English as the Journal of East Asian Architecture and Building Engineering, is a significant step forward in understanding and addressing the unique challenges posed by these structures. As we continue to push the boundaries of urban development, it’s crucial that our design methods keep pace. After all, the safety of millions of people could depend on it.