On October 20, 2026, at the construction site of Changhai Bridge, the first 40 meter precast concrete box girder was smoothly hoisted into place by the bridge erecting machine. With the cooperation of the gantry crane, the box girder is slowly lifted and accurately erected towards the bridge position.

This time, the box girder is erected with a maximum weight of 330 tons per beam, designed to enhance durability in the high chloride ion corrosion environment of the Yellow Sea. The total width of the bridge deck is 21 meters, connected as a whole by 4 box girders through wet joints, using a "simple support first and then continuous" structural system. The requirements for large tonnage, multi beam type, and marine anti-corrosion have raised higher demands on prefabrication quality, transportation organization, and installation accuracy.

The project is equipped with a 400 ton double guide beam gantry crane, a 470 ton tire type beam transport vehicle, a 400 ton beam moving machine, and two 220 ton gantry cranes to construct a complete set of operation system from beam lifting, transportation to bridge site installation. A box girder can be transported from the beginning to the final installation in just one and a half hours.

The box girder of Changhai Bridge adopts multiple new technologies from prefabrication, and the supporting smart box girder field covers an area of 140000 square meters, equivalent to 20 standard football fields. It has 10 functional areas and 4 automated production lines. It adopts a flow operation system and is equipped with high-temperature steam curing and intelligent tensioning equipment. The production cycle of single box girder has been shortened from 10 days to 4 days.

During the process of box girder erection, the bridge erecting machine and transportation equipment work together, and the digital monitoring system cooperates with multi-point synchronous lifting control to support attitude control and millimeter level positioning, ensuring smooth lifting and precise positioning of large tonnage box girders.

After the successful installation of the first box girder, the project command center will continue to coordinate resources, strengthen technical support, improve engineering quality and construction efficiency through intelligent construction, and actively respond to challenges such as ocean corrosion and complex sea conditions.

This article is reprinted from: China Construction Eighth Engineering Division Northeast Company       Editor/Gao Xue