On the evening of December 8, the world's largest concrete-filled steel tube arch bridge with an overall lifting span and tonnage of arch ribs - Pinglu Canal Jiuzhou Bridge successfully completed the concrete pouring in the main chord pipe of the last arch rib. So far, the 8 arch rib main chord pipes of the bridge have all completed the concrete pouring in the pipe, and the bridge is about to enter the lattice beam hoisting construction stage.
The Pinglu Canal Jiuzhou Bridge is located in Lingshan County, Qinzhou City, the main bridge spans the Pinglu Canal of the century project, and the approach bridge crosses the Liqin Railway, which is invested and constructed by Guangxi Beibu Gulf Investment Group, a direct subsidiary of Guangxi Beibu Gulf Investment Group. The bridge is 525 meters long, the main bridge is a 260-meter-diameter under-supported concrete-filled steel tube tie arch bridge, a total of 8 main chord pipes, the concrete in the pipe is made of C50 self-compacting compensation shrinkage concrete, the total pouring volume of the whole bridge is about 1901 cubic meters, divided into five pourings.
Concrete pouring in the pipe is an important part of the construction of concrete-filled steel tube tied arch bridge, and the pouring quality directly affects the safety stress state of the bridge and the later use effect. The construction team has held technical seminars for many times to make technical disclosures on concrete mix ratio, mechanical combination, pumping method, inspection method and other contents.
During the pouring period, the construction team strictly controlled the concrete mix ratio to ensure that the performance of the concrete reached the best state. The project is equipped with 14 concrete transport tankers and 6 high-pressure pump trucks, and nearly 150 management personnel and operators are invested to ensure the sufficient and efficient cooperation of mechanical equipment and post personnel at each site, and to ensure the orderly and controllable construction site and the quality and continuity of concrete pouring.
At the same time, the construction team, together with the scientific research team of the university and the third-party testing unit, uses high-precision automatic measuring instruments such as automatic measuring robots to monitor the deformation of the arch rib transverse bridge, the deformation of the arch rib, the displacement of the arch seat, and the structural force in the perfusion stage, and compares the temperature correction and theoretical calculated values in real time, and does a good job in technical tracking and dynamic feedback throughout the whole process to ensure that the deformation and force of the arch rib are in a stable state during the perfusion construction.
With the continuous advancement of the concrete pouring in the main chord pipe of the arch rib of the bridge, the weight and force of the arch rib continue to increase, and the construction team should tension the temporary tie rod of the arch to maintain the stress balance of the arch rib for each completed concrete pouring of the main chord tube on the left and right widths. On the basis of the overall improvement of the intelligent tensioning system of the arch ribs, the construction team combined with BIM application technology to further optimize and improve the self-developed "Pinglu Canal Jiuzhou Bridge Digital Twin Intelligent Display and Control System". The system is connected with the multi-source perception system to analyze, process and monitor the real-time data of the displacement, stress and other elements of the main arch and arch, so as to realize the intelligent construction of the bridge and ensure the overall quality and safety of the project. (Shi Ruipeng, Guangxi Reporter Station of China** Agency).
*: China**Net.