Breakthrough progress! The main channel bridge of Longmen Bridge has officially entered the steel box girder hoisting stage. The main channel bridge | steel box girder | bridge
On July 30th, the Longmen Bridge project, the longest under construction cross sea bridge in Guangxi, made breakthrough progress: the first section of the main waterway bridge, weighing 265.2 tons, was successfully lifted and swung onto the sliding bracket, slowly sliding to the predetermined position, marking the official entry of the Longmen Bridge into the steel box girder hoisting construction phase.
The Longmen Bridge project has a total length of 7.6 kilometers, of which the main navigation bridge adopts a single span floating system steel box girder suspension bridge with a main span of 1098 meters. The main span steel box girder extends 50 meters to both sides of the side span, and a total of 96 steel box girders need to be lifted for the entire bridge. The first section of the steel box girder on the west bank of the bridge is being lifted, which is 10.93 meters long, 38.6 meters wide, 3.2 meters high, and weighs 265.2 tons.
In the afternoon of that day, after the beam carrier carrying the steel box girder anchored and positioned on the shore, the construction personnel lowered the cable crane lifting device and connected it to the temporary lifting point on the steel box girder. They used the tower top gantry hoist as the power equipment for the swing and anti pull system, and connected the swing and anti pull steel wire ropes to the cable crane lifting device. Then start the cable mounted crane, slowly lift the steel box girder, and cooperate with the swing and anti pull system to lift the side span steel girder to the shore sliding bracket.
Due to the complex marine environment and frequent typhoons and monsoons in the main channel of Longmen Bridge, higher requirements are put forward for wind resistance of the bridge. In order to solve construction technical problems, the project command center actively organizes research institutes, design units, construction units, and industry experts to carry out a series of technological innovations to improve the wind resistance of the bridge.
The design innovation of the steel box girder of Longmen Bridge in terms of aerodynamic shape is to eliminate the traditional wind nozzle structure and adopt a new section form of straight web plate+"inverted L-shaped" guide plate at the end design. The position of the maintenance vehicle track at the bottom of the girder is optimized to improve wind resistance performance. After wind tunnel experiments by the technical team, the maximum wind resistance speed of this steel box girder form can reach 140 meters per second, exceeding the super typhoon intensity of level 17 or above and far exceeding the industry's wind resistance design standard of 80 meters per second.
At present, the construction of Longmen Bridge is steadily advancing, and the construction of the entire lower structure such as pile foundation, bearing platform, and pier body has been completed. The construction of the auxiliary channel bridge box girder has been completed by 75.8%, and it is expected to achieve full left span connection of the bridge by the end of the year.
After the completion of the Longmen Bridge project, it will open up the "checkpoints" on the coastal highway in Guangxi, effectively promoting the integration process of "North Qinzhou Defense", and reducing the time and space distance between Qinzhou Port and Fangcheng Port from the original 1.5 hours to about 25 minutes.
