Seismic Performance Evaluation of a Diagrid Braced Dual System on Sloping Terrain Considering Soil Structure Interaction

Abstract: - In recent years, rapid urbanization and scarcity of land have led to the construction of high-rise buildings, especially in challenging conditions such as sloping terrain. These structures are highly vulnerable to seismic forces due to irregular geometry, varying stiffness, and complex load distribution. Therefore, it becomes essential to study their behavior under earthquake loading conditions using advanced structural systems and realistic analysis approaches. In this study, the seismic performance of a G+10 diagrid braced dual system building on sloping terrain is evaluated by considering the effect of soil–structure interaction (SSI). The diagrid structural system is adopted due to its high efficiency in resisting lateral loads through its triangulated configuration, which enhances stiffness and reduces material consumption. The analysis is carried out using SAP2000 software by performing nonlinear time-history analysis with the El-Centro earthquake record. The building is modeled under two base conditions, namely fixed base and flexible base (with SSI). The SSI effect is incorporated using the Winkler spring model, considering different soil types such as hard soil, medium soil, and soft soil. The performance of the structure is evaluated based on key seismic parameters such as storey displacement, maximum displacement, time period, storey drift, and base shear. The results indicate that the inclusion of soil–structure interaction significantly influences the dynamic behavior of the building. It is observed that displacement and time period increase with the flexibility of soil, particularly in soft soil conditions, while base shear decreases due to the damping effect of soil. The diagrid system demonstrates improved performance in terms of load distribution and lateral resistance compared to conventional systems.