On October 12, after 40 days of unremitting struggle, the steel-concrete composite beam of the Beihe Bridge of the Shanmei Expressway Reconstruction and Expansion Project, which belongs to Guangdong Communications Group and was undertaken by China Railway Fourth Bureau, successfully completed the jacking operation.
The construction site of the Beihe Bridge
The Beihe Bridge is located in Yuhu Town, Jiedong District, Jieyang City, and is renovated and expanded in a separate and new way, that is, on the basis of retaining the original Beihe Bridge as the left width, the new right width is built. The new right Beihe Bridge is designed to be 6 joints and 24 spans, with a total length of 605 meters and a bridge deck width of 20.5 meters.
Among them, the three-span continuous steel-concrete composite beam spanning the north section of the Rongjiang River is a composite structure of "trough steel box girder + precast concrete bridge deck", which is constructed by jacking method, which is also the steel-concrete composite beam with the largest span in the whole line of the Shanmei Expressway Reconstruction and Expansion Project.
Jacking construction is a steel box girder installation process, it is an important process of steel girder installation, through which each section of steel girder installation, cyclic jacking, and finally complete the whole bridge segmented installation. In the actual construction, the difficulty of the jacking operation lies in the control of the steel beam alignment and the lateral deviation correction of the whole bridge in the process.
The Beihe Bridge is undergoing steel box girder jacking operations
Before each round of operation, the construction personnel need to carry out the procedures such as path interference investigation before pushing, the release of the cushion constraint, and the debugging of the jacking system, and then the jacking makes the steel beam break away from the pier and pushes forward, and the steel beam falls on the pier after the roof falls, and finally returns to the top, so that the cycle operation. "Each round of jacking takes an average of five hours, and a total of 18 rounds of jacking operations are carried out on the whole bridge." Jia Yongshun, secretary of the TJ1 standard for the reconstruction and expansion of Shanmei Expressway, introduced.
The steel box girder used for the jacking operation is about 128.5 meters long and weighs about 1,400 tons. In order to realize the steel beam curve jacking, the project adopts the walking curve jacking method, arranges the jack on the jacking curve path, and accurately controls the jacking displacement of the inner and outer jacks through the jacking multi-point synchronization system, so as to realize the steel beam curve jacking.
The construction site of the Beihe Bridge
The project set up 5 groups of walking jacks at the bottom of the steel box girder, 2 in each group, a total of 10. In the process of pushing, the walking jack console can be controlled synchronously, and the displacement, pressure and reaction force of each jack can be displayed in real time, and the whole process of jacking can be monitored in real time, and the linear displacement of the jacking can be controlled at the millimeter level, and the error is within the allowable range of the design, so as to finally achieve accurate docking.
In order to ensure the smooth completion of the jacking, the project also adopts the intelligent monitoring cloud platform of the engineering pulse to monitor the mechanical behavior of the box girder jacking, bridge health monitoring and safety control technology throughout the process to ensure the safety and efficiency of the construction.
The successful completion of the jacking operation of the steel-concrete composite beam of the Beihe Bridge not only created a good situation for the subsequent construction of the bridge deck, but also laid a solid foundation for the first traffic diversion and reform of the Shanmei Expressway Reconstruction and Expansion Project.
South+ reporter He Yuanni
Correspondents: Liang Jie, Zhou Xuyan, Ji Na
【Author】 He Yuanni
[Source] Southern Press Media Group Southern + client