In the early morning of Hangzhou Bay, the tide beats against the bridge piers. At around 7:00 am on July 23rd, a huge crane ship was stretching its long arm on the sea surface about 1.3 kilometers away from the Haiyan coastline in Zhejiang. With the command of the commanding personnel, a 12 meter high and 762 ton "steel giant" slowly left the ship and smoothly moved in the air. Two hours later, it was precisely seated on Pier 14. This suspension not only declares the completion of the lower structure of the sea salt section of the bridge, but also fills a gap in the construction of cross sea railway bridges in the world.

Building blocks in the sea

The bridge pier is the backbone of the bridge, carrying the weight of a speeding train. Traditional cross sea bridge piers are often cast on-site, which not only has a long construction period but also faces complex maritime meteorological challenges. In this construction, the builders divided the pier body into several sections, prefabricated them on the shore like industrial products, and then transported them to the sea for assembly. This method, similar to children building blocks, allows Pier 14 to be perfectly interlocked with one cast-in-place section and three prefabricated sections. In fact, prefabrication technology has been applied in highway bridges such as the Hong Kong Zhuhai Macao Bridge, but the construction of railway piers on rough seas is still the world's first.

Invisible Strong Adhesive

How to make the spliced bridge piers as solid as a rock? The construction team demonstrated their unique skills. They abandoned the traditional connection method and innovatively adopted self-locking prestressing combined with adhesive joint technology. Simply put, it is to apply high-performance epoxy adhesive on the contact surface of the pier body. It is like an invisible strong adhesive, and the bonding strength after curing even exceeds that of the concrete itself, which can resist the severe temperature difference and strong typhoon invasion in Hangzhou Bay. Subsequently, the construction personnel tensioned the prestressed steel strands and tightly embraced each section of the pier body into a whole, capable of withstanding the high-frequency loads brought by high-speed rail travel.

Sprint towards a new landmark

With the final prefabricated pier body in place, the construction of the Hangzhou Bay Cross Sea Railway Bridge has entered the fast lane. At present, the overall progress of the Haiyan section project has exceeded 80%. The North Channel Bridge is poised to take off and is planned to be completed in September this year; The sea approach bridge has also completed the installation of 67 precast box girders. As a controlling project of the Tongsu Jiayong high-speed railway, this world-renowned cross sea bridge is expected to be ready for operation by the end of 2027. At that time, it will not only reshape the transportation map of the Yangtze River Delta region, but also provide a highly valuable "Chinese solution" for global cross sea railway projects.Editor/Yang Meiling