Thăng Long Bridge

The Thăng Long Bridge (Cầu Thăng Long, completed 1978) is a two-level crossing over the Red River in northern Hanoi. It forms a key segment of Ringway 3 of Hanoi, connecting the city center with Noi Bai International Airport and provinces in the northwest of Vietnam. The bridge stands as a lasting tribute to Soviet–Vietnamese cooperation, a role reflected in its alternative name “Friendship Bridge” and memorial features at both ends. History Work on Thăng Long Bridge began on 26 November 1974 under a Chinese-supported design, but halted in 1978 when Chinese aid was withdrawn. At that time, the structure was only ≈20% complete. In June 1979, the Soviet Union resumed the project under an Vietnam–Soviet agreement dated 3 November 1978, supplying materials and expertise. The bridge was completed and inaugurated on 9 May 1985, after nearly 11 years of construction. Technical specifications The Thăng Long Bridge is a two-level structure designed for both railway and roadway traffic. Its superstructure consists of steel girders for the main spans and prestressed reinforced concrete girders for the approach spans. Load design Railway load: Designed for a C12-class train. Motor vehicle load: Designed for H30–HK80 vehicle convoys. Light vehicle/bicycle lanes: Uniform load of 400 kg/m² or a single 13-ton vehicle. Pedestrian load: 300 kg/m². Navigational clearance: Ensures safe passage for 3,000-ton vessels at +11.10 m water level. Structure and dimensions Main bridge (spanning the Red River): Length: 1,688 m Structure: 15 continuous steel girder spans Each girder unit: 3 spans × 112 m Supported by 14 piers and 2 abutments, each pier containing ~10,000 m³ of concrete Total: 5 continuous girder units Lower deck – Railway Total length: 5,503.3 m Deck width: 17 m Rail: Two tracks – one standard gauge (1.435 m), one meter gauge (1.0 m) Each side includes a 3.5 m lane for light vehicles Vertical clearance from upper to lower deck: 14.10 m Approach spans: 116 prestressed concrete girders, each 33 m long (53 north, 63 south) Upper deck – Roadway Total length: 3,116 m Deck width: 19.5 m, including: 16.5 m for four lanes of vehicles Two sidewalks, each 1.5 m wide Superstructure: 6,500 tons of orthotropic steel plates, 14 mm thick Reinforced with longitudinal and transverse stiffeners Welds: Over 30 km of automated welds inspected via ultrasonic and X-ray testing (first used in Vietnam) Approach spans: 43 prestressed concrete girders, 33 m each (22 north, 21 south) Light vehicle access Total length: 2,658.42 m Includes 29 additional approach spans (14 north, 15 south) and side lanes on lower deck Materials and construction Concrete volume: 230,000 m³ Structural steel: 53,294 tons Precast girders: 946 units, each weighing 54–130 tons Prestressed spun piles: 110,000 m of Ø550 mm piles Technical upgrades and usage In 2009, the bridge underwent a major refurbishment phase, including the replacement of expansion joints, repainting, and application of ultra-high-performance concrete overlays. A subsequent major repair completed in 2021 included reinforcement of the steel deck and structural elements, costing about VND 270 billion (~US$11.7 million). References