Project Overview
The B3 Arch Bridge, a key control project on Georgia’s North‑South Corridor Road Section, is an upper‑deck reinforced‑concrete arch bridge constructed by China Railway 23rd Bureau Group Co., Ltd. It measures 437.875 meters in total length, features a main arch clear span of 286 meters, and provides a vertical clearance of 164 meters from the deck to the valley bottom. The bridge employs a cable‑stayed tie‑back system and is built using cantilever casting with form travelers.
Environmental Challenges
The bridge site lies in a mountainous canyon where extreme climatic conditions prevail: regional wind speeds can reach Level 9, winter temperatures may drop to –20 °C, and snow depth can accumulate up to 2 meters. These factors create stringent safety and stability challenges during both construction and operation.
Wind‑Tunnel Testing Programme
Two comprehensive wind‑tunnel test campaigns were conducted at the National Key Laboratory of Bridge Engineering Safety and Resilience of Hunan University. The first campaign involved a full‑bridge model to verify long‑term wind‑resistance performance during the operational phase, establishing a closed‑loop safety verification system for the entire project lifecycle. The second campaign focused on the high‑risk asymmetric construction condition associated with the left‑side arch‑ring closure scheduled for 2026, simulating unbalanced forces, canyon turbulence, and aerodynamic interference between the twin arches.
Test Standards and Compliance
All tests were performed in strict accordance with FIDIC contract provisions and European engineering standards, ensuring the reliability and authority of the measured results.
Test Results and Safety Conclusions
The test outcomes indicate that, upon completion, the bridge will be capable of withstanding extreme winds far exceeding those of a once‑in‑100‑year event. During the 2026 asymmetric arch‑ring closure, wind‑induced vibration, deformation, and structural stresses are projected to remain within safe and controllable limits, meeting all contractual and technical specification requirements. The integrated results from both test rounds have been used to optimise wind‑resistance and vibration‑control construction procedures and on‑site control measures, establishing a comprehensive safety system covering construction, arch closure, and operation.
Technological Significance
Compared with conventional theoretical calculations, the physical model testing adopted for this overseas project markedly improves safety‑assessment accuracy and represents an upgrade in wind‑resistance technology for long‑span arch bridges. The project demonstrates the application of top‑tier domestic scientific research capabilities and mature empirical technologies to meet European and international construction standards in a complex cold‑climate canyon environment.
Next Steps
The project team will implement the derived safety control measures, continue steady construction progress, and aim to achieve the left‑side arch‑ring closure milestone in 2026, thereby showcasing China’s infrastructure construction strength and international project delivery capabilities.