Static Wind Stability Calculation and Analysis of Large-Span CFST Arch Bridge

Literature Overview

This paper by Yu Honggang, Ge Yaojun, Zhang Wei, and Yang Yongxin, published in Bridge Construction, Volume 37, Issue 2, 2007, presents the static wind stability analysis of the Sanmenkou Cross-Sea Bridge North Gate Bridge, a 270-meter span steel tube concrete (CFST) middle-supported arch bridge. Funded by the National Natural Science Foundation of China (Project No. 50278069), the research was conducted at the State Key Laboratory for Disaster Prevention in Civil Engineering at Tongji University.

Bridge Description and Structural Configuration

The Sanmenkou Cross-Sea Bridge North Gate Bridge is a medium-span CFST arch bridge with a main span of 270 meters. The bridge adopts a middle-supported arch configuration, where the steel tube concrete arch ribs are positioned at the mid-height of the deck. This structural arrangement provides efficient load transfer and favorable aerodynamic characteristics.

Wind Load Analysis Methodology

The study combines wind tunnel testing and numerical analysis to determine the static wind coefficients for the bridge. The key analytical steps include:

Key Technical Findings

The Reynolds number correction of the arch rib three-component force coefficients is a critical aspect of this study. Wind tunnel testing typically uses scaled models, and the Reynolds number of the model may differ significantly from that of the full-scale bridge. Without proper correction, the aerodynamic force predictions may be inaccurate, leading to either unsafe or uneconomical design.

The static wind stability verification was performed for both the construction stage and the completed bridge condition. The results demonstrate that the anti-wind stability requirements are satisfied in both stages, confirming the structural adequacy of the design.

Construction Stage Considerations

The construction stage analysis is particularly important for large-span CFST arch bridges. During construction, the arch ribs are erected progressively, and the structural configuration changes continuously. The wind exposure and aerodynamic characteristics of the partially constructed bridge differ significantly from those of the completed structure. The study confirms that the bridge maintains adequate stability throughout the entire construction sequence.

Engineering Practice Implications

For engineers designing large-span CFST arch bridges, this study provides several important guidelines:

• Always perform Reynolds number correction on wind tunnel test data to ensure accurate aerodynamic force predictions.
• Verify static wind stability for both construction and completed bridge conditions.
• Consider the three-component force coefficients (longitudinal, lateral, and vertical) in the stability analysis.
• Use finite element analysis to assess the structural response to wind loads with appropriate safety margins.
• Pay special attention to the aerodynamic characteristics of the CFST arch ribs, which are critical to the overall wind stability of the bridge.

Study Insights and Reflections

This study exemplifies the rigorous approach required for the wind stability assessment of large-span bridges. The combination of wind tunnel testing and numerical analysis, with proper Reynolds number correction, represents best practice in bridge aerodynamics. The CFST arch bridge configuration offers excellent structural efficiency and favorable aerodynamic properties, but the wind stability must be rigorously verified for both construction and service conditions. Engineers should note that the static wind analysis addresses steady-state wind loads and does not account for dynamic wind effects such as vortex-induced vibration or flutter. These dynamic effects should be assessed separately, particularly for bridges with slender arch ribs and long spans. The successful verification of wind stability for this 270-meter span CFST arch bridge provides valuable reference data for similar bridge designs.