Ou River North Estuary Bridge

A Dual‑Deck Landmark

  Stretching 7.9 kilometers across the Oujiang River, the Oujiang Beikou Bridge connects Huanghua in Yueqing with Lingkun Island. The bridge carries six lanes of traffic with a design speed of 100 km/h. The main structure is all steel, spanning the river in two sections.

Three World Firsts

  Upon completion, the North Mouth Bridge was one of the most technically challenging and complex bridges ever built in China and beyond. It set multiple world records.

• The world's first three‑tower, four‑span, double‑deck steel truss suspension bridge

• The first application of a rigid concrete middle tower in a multi‑tower and multi‑span suspension bridge

• The first super‑large caisson foundation in deep soft soil at a macro‑tidal river estuary

  The Oujiang Beikou bridge is the final section of China’s coastal artery, the Yongguan Expressway. Its completion closed the remaining gap on the Zhejiang section of G1523. As one of the first green highway demonstration projects under the Ministry of Transport, the bridge adopts a dual‑deck design that combines highway and national road traffic into a single structure, saving approximately 12.8 hectares of land. The upper deck carries expressway traffic, while the lower deck serves as a national highway.

"ROABY's Efforts

  Two critical components of this landmark bridge—the expansion joints and the lower‑deck pavement—were delivered by ROABY.

  The Oujiang Beikou bridge's main structure uses a steel truss suspension system with two main spans. Combined with the challenging conditions of strong typhoons and large tidal surges, the bridge's connections require accommodation of complex multidirectional movement. ROABY's Unitized Multidirectional Expansion joint System was installed to meet these demands. Given the high traffic volume, the system also incorporates anti‑warping, anti‑settlement, and non‑motorized traffic compatibility features to ensure safe operation.

  Located at the Oujiang River estuary, the bridge faces complex hydrology, challenging geology, and world‑class engineering difficulty—demanding better pavement performance. The surfacing must withstand high temperatures, strong tides, soft soil, and corrosion. Conventional asphalt pavement deforms under heat, generates heavy emissions during application, resists corrosion poorly, and often requires frequent patching or full replacement under heavy traffic. ROABY ECO polyurethane material ushers in a post‑asphalt way for bridge deck paving.

  The ECO polyurethane pavement achieves a permeability rating of P12 and chloride ion permeability below 100 coulombs, making it well suited for marine environments and effectively addressing common durability issues on steel bridge decks in coastal areas. The material contains no asphalt, eliminating asphalt fumes during production and application. It is mixed and applied at ambient temperature without heating, reducing energy consumption and emissions. ROABY completed the lower‑deck steel pavement for the Oujiang Beikou Bridge in just 16 working days (192 hours).

  The ECO polyurethane system was selected for its combination of environmental performance and durability. The modified material effectively extends steel bridge deck service life and recommends its use for steel deck applications. Service life for ECO polyurethane on steel bridge decks is estimated at 5 to 10 years—more than three times that of conventional systems—and 20 to 30 years on concrete decks, nearly ten times that of conventional asphalt.

Key Figures

World's first three‑tower, four‑span, double‑deck steel truss suspension bridge

Two critical applications from ROABY: expansion joints and ECO polyurethane pavement