At 5:18 p.m. on January 31, 2021, with the 3600 ton crane ship "Haiou" lifting the steel box girder weighing about 2220 tons in place, the erection of the first section of steel box girder of Jinhai bridge, the world's first multi tower cable-stayed bridge on the same floor built by China Railway Bridge Bureau, was completed.

The steel beam is 46 meters long, 50.2 meters wide (including the wind nozzle), 8.6 meters high. Its area is equivalent to the size of 5.5 basketball courts. It has the characteristics of large structure size, heavy weight, complex stress, new manufacturing and installation technology. The erection of super heavy steel beam needs the cooperation of various ships, the hoisting process is complex, and the organization and coordination workload is large.

In order to deal with all kinds of difficulties in the process of steel beam erection, the project department planned in advance, prepared a variety of work plans, and practiced and improved the cooperation mechanism among floating crane, tugboat and anchor boat in advance, so as to ensure the safety control of steel beam erection.

The steel box girder manufacturing of the project has the characteristics of "large-scale, industrialized, standardized and assembled". The steel box girder is manufactured in the factory as a whole, transported to the bridge site by water, and then installed by the "Seagull" crane ship.

During the mission, because the bridge site is located at the mouth of Xijiang River, the natural water depth is shallow, so it is difficult for large ships to enter the site. Therefore, the construction personnel overcame the difficulties of tide and siltation and dredged the channel ahead of time, which effectively ensured that the crane ships could enter and lift on schedule.

Compared with segmental hoisting, the whole segmental installation transforms the high altitude operation into low altitude operation, the on-site operation into factory operation, and the labor-intensive construction into mechanized construction, which effectively reduces the risk of on-site water and high altitude operation and shortens the construction period for more than half a year.

The bridge was started in April 2018. Since its construction, it has experienced adverse conditions such as super typhoon "Shanzhu" and high temperature rainstorm, as well as many difficulties caused by the epidemic. At present, the steel box girder, steel tower erection and continuous rigid frame construction of the bridge have been in full swing. During the Spring Festival, the heaviest steel girder erection and the most difficult steel main tower hoisting will be carried out. The bridge is expected to be officially completed and opened to traffic in 2023. (please refer to www.seetao.com for reprint.  ）Editor of seetao.com / Sun Mengmeng