At 11:06 a.m. on November 10, 2020, with the last concrete being poured into the 28th section of the tower column formwork on the left of the main tower, the world's largest single-tower single-span steel box girder suspension bridge built by China Railway Bridge Bureau-Yuchu Expressway The main tower of the Lvzhijiang Bridge is topped off.

The Lvzhi River Bridge is a key control project of the Yuxi-Chuxiong Expressway. It is located at the junction of Yimen County and Shuangbai County. It crosses the Lvzhi River and is directly connected to the tunnel on both sides. The bridge has a total length of 798 meters, a two-way four-lane bridge deck, and a design speed of 100 kilometers per hour. As the first single-tower single-span steel box girder suspension bridge in the country, the 780-meter span of the Lvzhijiang Bridge ranks first among similar types of bridges in the world; the Yuxi'an tunnel anchor bottom plate has an inclination angle of 54°, which is currently the largest tunnel anchor in the country.

The main tower of the bridge is a double-tower portal frame structure. The tower column is 156 meters high and is divided into 28 sections. The pouring site is the last section of the bridge main tower. A total of 113 cubic meters of concrete was poured, which took 6 hours to complete.

In order to speed up the progress of the project and strive to win the "double victory", the China Railway Bridge Bureau Yuchu Expressway Lvzhijiang Bridge Project Department took the "100 Days of Work" labor competition as an opportunity to plan ahead and innovate boldly, adopting "post-beam construction + master" The “tower first construction” plan shortened the construction time of each section from the original 7 to 8 days to 6 days, making the main tower capping time one month earlier than the original plan; in view of the structural difficulties of the Yuxi Bank Tunnel with large anchor inclination, the project department responded The method of slagging out of tunnel anchors has been technically researched, and a set of rapid and intelligent slagging system has been independently developed, which effectively shortens the construction period of Yuxi's tunnel anchors; combined with BIM technology to establish a 1:1 engineering model to generate key parts of the main tower and complex parts of the structure The three-dimensional model visualizes abstract technical problems; through the establishment of an information platform and integrated big data management for data statistics, the traceability of construction raw materials is realized. The construction of the Lvzhijiang Bridge started on April 1, 2019. After nearly 20 months of overcoming difficulties by the builders, the construction of cast-in-place beams of the approach bridge and the processing of steel box beams are currently underway. The anchor plug bodies of the tunnels on both sides of the bank are being constructed. The entire bridge has completed 60% of the total engineering volume. Next, the bridge will be transferred to the upper steel box girder assembly and construction phase and the tunnel excavation.Editor/Luo Wentao