On January 11, with the lifting of the last arch ring segment, the right-span main arch ring of the Wumengshan Bridge on the Naqing Expressway, constructed by the Highway Group under Guizhou Communications Construction Group, was successfully closed, marking that the bridge has officially entered the construction of the spandrel structure and laying a solid foundation for the subsequent construction of the Naqing Expressway on schedule.

The Wumengshan Bridge is one of the controlling projects and also one of the major difficult projects of the Naqing Expressway. The left span of the bridge is 491.5 m long and the right span is 511.5 m long; it is a typical deck-arch bridge with two-way six lanes. The bridge crosses the Azhi River canyon and the slopes on both sides, with a maximum ground cross slope of nearly 65 degrees. To adapt to this complex terrain, the bridge type scheme, in combination with the actual terrain, geological conditions, dangerous rock zones and other conditions at the bridge site, adopts a steel truss-concrete composite structure for the main arch ring. This structure is used for the first time on an arch bridge and, once completed, the bridge will become the world's first steel truss web member-concrete composite arch bridge.

"This new bridge structure, the truss web member-concrete composite arch bridge, is based on the arch with a stiff skeleton and externally wrapped concrete, and uses steel web members to replace concrete webs, which can reduce the dead weight of the main arch ring by 27% and the engineering quantity of the arch abutment by about one third," Zong Wei, deputy chief engineer of the Naqing T12 project of Guizhou Highway Group, told reporters. The Wumengshan Bridge is constructed in left and right spans. The main arch ring construction adopts the group's self-developed large-segment arch rib precasting and assembly technology and the "large-tonnage towerless movable cable hoisting system," which greatly reduces construction costs while improving construction efficiency and reducing the risk of work at height.

The main arch ring of the Wumengshan Bridge is constructed by precasting and hoisting. After the main arch ring segments are precast on the jigs, they are hoisted and installed using the large-tonnage, towerless, movable cable hoisting system.

"The Wumengshan Bridge combines a new bridge type, new processes and new technologies. The construction of this bridge will promote the application of steel truss web member-concrete composite arch bridges in deep mountain canyons, further advance the development of the transportation industry in Liupanshui City, and is of great significance for improving the skeleton road network structure of Guizhou's highway trunk lines, improving Guizhou's transportation pattern, and promoting tourism and social and economic development in Liupanshui," said Xie Fangchen, Party branch secretary and chairman of Guizhou Naqing Expressway Co., Ltd.

With the smooth closure of the right span, the overall construction progress of the Wumengshan Bridge has reached 65.79%. Next, the project department will continue to strengthen construction organization and optimize resource allocation, accelerate the hoisting of the left-span segments and the subsequent superstructure construction of the bridge, and ensure that the Wumengshan Bridge is completed as soon as possible.