Research on Dynamic Characteristics and Seismic Response of Suspen-Dome Structures Accounting for the Influence of Substructure Stiffness: Shaking Table Test and Numerical Analysis

This paper examines the dynamic characteristics and seismic responses of suspen-dome structures, incorporating the influence of substructures, using the Lanzhou Olympic Sports Center Comprehensive Gymnasium with a symmetric suspen-dome roof as a case study. A scaled test model with a 1:20 ratio was developed, and a novel approach to simplifying the complex substructures of the prototype structure within the scaled model was proposed. The accuracy of this method was validated. Subsequently, both an overall numerical model and a simplified numerical model (excluding substructures) were constructed. Their natural frequencies and seismic responses were compared. Additionally, the impact of substructure stiffness on dynamic characteristics and seismic responses investigated. The findings reveal that substructures decrease the natural frequencies of the suspen-dome structure while amplifying its seismic responses. The maximum relative error of the natural frequencies between the overall model and the simplified numerical model is as high as 25.9%; and the maximum relative difference in acceleration, displacement and strain between the two models can reach 0.71 g, 1.27 mm and 181.6 με, respectively. Thus, the inclusion of substructure effects is critical in the seismic analysis of suspen-dome structures. Moreover, as substructure stiffness decreases, the natural frequencies of the suspen-dome structure are reduced, and the vibration mode shifts from superstructure deformation to cooperative deformation involving both the superstructure and substructure. Finally, variations in substructure stiffness influence the constraints on the superstructure or the fundamental frequency of the overall structure, and consequently, the seismic responses of the suspen-dome structure. Thus, when performing seismic analyses, it is essential to design appropriate substructure stiffness and consider the specific characteristics of the building site.