Zhuojin Pipe Fitting Co., LtdConstruction Control Technology for CFST Tie-Arch Bridge
Literature Overview
The paper by Sun Jiuchun, Cao Hong, and Xi Guodong, published in Construction Technology (Chinese and English) (Vol. 51, No. 15, 2022, pp. 67-71), presents a comprehensive construction control technology study for a CFST tie-arch bridge. The research was funded by Tengda Construction Group Co., Ltd. as a corporate research project on CFST arch bridge construction monitoring technology (Project No. 2020-HZ-007). This study is highly practical and directly applicable to construction management of large-span CFST arch bridges, addressing the critical challenge of ensuring structural integrity and geometric accuracy during construction.
Key Construction Phases and Control Points
The construction of a CFST tie-arch bridge involves several critical phases, each requiring careful control to ensure the final as-built structure meets design requirements. The key construction phases identified in this study include:
- Tie beam concrete pouring
- Steel arch rib installation
- Hanger rod installation
Each phase presents unique challenges and requires specific monitoring and control measures to ensure structural safety and geometric accuracy.
| Construction Phase | Key Control Parameters | Monitoring Method |
|---|---|---|
| Tie beam concrete pouring | Concrete strength, placement sequence, temperature | Concrete testing, temperature sensors |
| Steel arch rib installation | Deformation, stress, geometric accuracy | Strain gauges, displacement sensors, total station |
| Hanger rod installation | Cable force, stress distribution | Load cells, strain gauges |
| Overall structural control | Final geometry, stress state, stability | Comprehensive monitoring system |
Construction Monitoring and Control Strategy
The authors employed a full-process tracking monitoring approach, comparing measured results with theoretical calculation results to develop construction control technology. This approach involves continuous monitoring of tie beam and steel arch rib deformation and stress, as well as hanger rod cable force throughout the construction process.
The construction control strategy is based on the principle of comparing measured values with theoretical predictions and making adjustments as necessary. When deviations between measured and theoretical values exceed acceptable thresholds, corrective measures are implemented to bring the structure back within the design envelope. This real-time feedback control approach ensures that the final as-built structure meets the design requirements for geometry, stress state, and structural stability.
The concrete pouring sequence for the tie beam is critical to control the distribution of construction loads and prevent excessive deformation. The steel arch rib installation requires precise control of temporary support systems and the sequence of rib segment installation to ensure that the arch geometry develops correctly. The hanger rod installation and tensioning must be carefully sequenced to ensure uniform stress distribution and avoid local overstress in the arch ribs or tie beam.
Practical Engineering Insights
The construction control technology presented in this paper provides a practical framework for managing the construction of CFST tie-arch bridges. The emphasis on full-process monitoring and real-time comparison with theoretical predictions is a best practice approach that should be adopted for all large-span bridge construction projects.
For steel pipe fabrication and installation, the dimensional accuracy of the arch rib steel tubes is critical. Any deviations from the nominal geometry will affect the arch shape, stress distribution, and overall structural behavior. The fabrication quality of the steel tubes must be controlled to ensure that the as-built arch geometry matches the design geometry within acceptable tolerances.
The construction monitoring system should include strain gauges for measuring stress in the steel arch ribs, tie beam, and hanger rods; displacement sensors for measuring deformation; and load cells for measuring hanger rod cable forces. The monitoring data should be collected in real time and analyzed using appropriate software to provide immediate feedback to the construction team.
Study Reflections and Recommendations
This research demonstrates the practical application of construction control technology in a real CFST tie-arch bridge project. The approach of combining theoretical analysis with real-time monitoring provides a robust framework for ensuring construction quality and structural safety.
The study highlights the importance of construction sequencing and load management in CFST tie-arch bridge construction. The interaction between the tie beam, steel arch ribs, and hanger rods creates a complex structural system that requires careful management during construction to avoid excessive stresses or deformations.
For future projects, the construction control technology should be further refined through the use of advanced monitoring technologies, including fiber optic sensors, wireless sensor networks, and real-time structural health monitoring systems. The integration of construction monitoring data with structural health monitoring systems can provide a continuous record of the structure's behavior from construction through operation, enabling proactive maintenance and early detection of potential issues.
The construction control approach presented in this study should be adapted and applied to other types of large-span bridges, particularly those involving CFST members, where the interaction between steel and concrete components creates complex construction challenges.