**6. Conclusions and Future Plans**

With the establishment of a finite element numerical model of the MSL-S roof structure of the Fuzhou Strait Olympic Sports Center Gymnasium, this study analyzed the dynamic characteristics of string structures. The structural dynamic response under combined seismic excitation was studied through the nonlinear time history analysis method based on "self-weight" and the influence of different seismic impulses and near and far seismic fields on the dynamic response of the structure was studied. The conclusions are as follows.

1. The natural frequency of the first eight-order vibration modes gradually increased from 0.762 to 1.292, with the main vibration mode being the torsional deformation caused by the cables, while the last five mainly related to the overall roof plane vibration and antisymmetric vibration. Therefore, attention must be paid to the cable vibration of the structure.


The research focuses on the internal connection of the structural dynamic response between the cables, strut and roofs in the structural system of MSLSD, which predicted possible damage of the structure under different types of seismic excitation in advance and provided an important reference for structural seismic resistance. In addition, the research is relevant to the operation and maintenance of the building, including regular inspections. Due to the limitation of monitoring equipment, the existing monitoring system cannot collect corresponding data for all the key roof nodes to improve the monitoring database; the actual structure and the finite element model needs to be further optimized to analyze the structure dynamic response more accurately. At the same time, compared with the traditional string dome structure, the advantages and disadvantages of this new structure system (MSLSD) need to be further studied to provide a reference for promotion and improvement.

**Author Contributions:** Conceptualization, Z.L. and C.Z.; methodology, C.Z.; software, Z.L. and L.Y.; validation, Z.L., J.D. and C.Z.; formal analysis, J.O.; investigation, J.O.; data curation, L.Y.; writing—original draft preparation, Z.L.; writing—review and editing, Z.L. and J.D. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research is funded by the National Natural Science Foundation of China (Project No. E51508102). Natural Science Foundation of Fujian Province (Project No. 2019J05128). Natural Science Foundation of Fujian Province (Project No. 2019J01233).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** The authors declare no conflict of interest.
