Vinh Hung Completes Repair of Cau Lau Bridge

Panorama of the old Cau Lau Bridge (left) and the new Cau Lau Bridge (right)

The new Cau Lau Bridge crosses the Thu Bon River and lies on National Highway 1—a vital traffic route connecting Dien Ban Town and Duy Xuyen District in Quang Nam Province. It is also a major segment of the North–South traffic corridor. Opened in 2005, the bridge has handled a large volume of traffic, including heavy trucks and high-speed vehicles.

Originally designed according to AASHTO 1996 standards with an HS20-44 load rating, the bridge no longer meets the current HL93 load standard used in Vietnam and prescribed by later AASHTO LRFD guidelines. After over 20 years of operation, the bridge began to exhibit structural degradation, impacting safety. Without timely repairs, the structure’s lifespan would have been significantly shortened, and traffic safety seriously jeopardized.

Vinh Hung began construction on November 8, 2024, and completed the project on April 6, 2025.

Vinh Hung implemented a structural reinforcement solution for the cantilever box girder using external prestressed cables. Each span was equipped with 10 cable bundles. Of these, 8 bundles were positioned along the underside of the girder, following its curved bottom surface (bundles 1 to 8), while the remaining 2 bundles (numbers 9 and 10) were arranged near the neutral axis at the upper section of the box girder.

Each bundle contains 9 strands, with each strand made up of 7 high-strength steel wires. The strands are fully coated with epoxy according to ASTM A882 standards, with a diameter of 15.2 mm and a tensile strength of 1860 MPa. Each strand is encased in HDPE and internally lubricated with grease to improve durability and corrosion resistance under harsh environmental conditions.

External prestressing cables were anchored at specific points and span partitions to redirect force and enhance the overall stability of the girder structure. The cables were guided by steel pipes and HDPE ducts, and tensioned to a calculated stress of 52% of their ultimate tensile strength (fpu).

 Vinh Hung constructs prestressed cables to strengthen the anchor piers

In addition, Vinh Hung completed the prestressed cable reinforcement for three anchor piers located at spans 20, 21, and 22. These anchor piers are built from 45 MPa reinforced concrete, arranged symmetrically, and directly connected to the girder concrete.

To ensure timely progress, the engineering and construction teams embraced a spirit of urgency and dedication, working with mottos such as “working during the day is not enough, we work through the night,” “quick meals, short rests,” and “three shifts, four crews, nonstop 24/7.”

The successful completion of the Cau Lau Bridge Repair Project (new), located at Km953+340 on National Highway 1, holds great significance in restoring the bridge’s full operating capacity. It aligns the structure with the HL93 live load standard currently applied across National Highway 1, helps maintain structural longevity, and ensures quality and safety. Most importantly, it meets urgent transportation needs, supports daily travel for local communities, and contributes to the broader goal of ensuring national security and defense for Quang Nam Province and the country as a whole.