# Vibration Response Characteristics of Prefabricated Frame Structures Around the Subway
## 6 Conclusions  
Through systematic parametric studies of beam/column cross-sections, slab thickness, and total stories/spans under metro type B train running at 80 km/h vibrations, the following conclusions were drawn regarding semirigid and rigid connection systems:  
1. Beam section modifications demonstrated complex vibration control mechanisms influenced by both height and aspect ratio. Increasing beam height or aspect ratio (at constant height) achieved moderate acceleration reduction. While velocity spectral characteristics remained stable, peak velocity attenuation through height enhancement benefited long-term structural safety. Rigid-jointed systems showed greater sensitivity to beam parameter changes than semirigid configurations.
2. Column section enlargement demonstrated superior acceleration control efficacy to that of beam modifications. However, semirigid systems exhibited weaker column size effects than their rigid counterparts, often exceeding code-specified acceleration limits. Joint stiffness enhancement should precede column sizing optimization. Column parameter adjustments achieved greater peak velocity reduction than beam changes, establishing column design as a primary velocity-control strategy.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Direction**} & \multicolumn{2}{c}{**S1**} & \multicolumn{2}{c}{**S2**} & \multicolumn{2}{c}{**S3**} \\ \cline{2-7}  & **X** & **Y** & **X** & **Y** & **X** & **Y** \\ \hline Peak velocity & 1.653 & 3.592 & 1.241 & 3.139 & 1.020 & 2.612 \\ \hline \hline \end{tabular}
\end{table}
Table 15: Horizontal biaxial velocity peaks at the central positions of the top-floor slabs of different models.  
Figure 30: Horizontal biaxial velocity time-history diagrams at the central positions of the top-floor slabs of different models: (**a**) S1; (**b**) S2; (**c**) S3.  
3. Slab thickening achieved limited vibration reduction with critical thickness boundaries. Semirigid systems reached critical thickness thresholds earlier than rigid counterparts, making slab-based control unreliable for code compliance. While providing modest peak velocity reduction, slab optimization offered lower cost-effectiveness than beam/column modifications.
4. Structural heightening induced vibration attenuation with amplified roof-level responses, which were particularly pronounced in semirigid systems. Beyond a critical height (\(n=11\) stories), vibration distribution transitioned to initial attenuation followed by amplification. Frequency escalation impacts human comfort thresholds. Although reducing time-domain peak velocities, multispan nonresidential structures still require supplementary controls for strict compliance.
5. Span expansion significantly altered dominant frequencies and intensified edge effects in semirigid systems. Horizontal peak velocity reduction through span optimization provides effective safety assurance for metro-adjacent structures.  
Based on the shaking table test of prefabricated structures, this paper proposes a modeling method for concrete prefabricated frame structures to study the vibration response of structures on the site caused by subway operation. The relevant research can provide references for subway route planning, environmental vibration impact assessment of new structures, and design of control measures.  
Methodology, Y.Y.; Software, Z.H.; Writing--original draft, Z.H.; Writing--review & editing, Y.Y. All authors have read and agreed to the published version of the manuscript.  
This research was supported by the Chongqing construction science and technology project (Project No. 2023-3-14).  
Not applicable.  
The raw data supporting the conclusions of this article will be made available by the authors on request.  
The authors declare no conflict of interest.