The center arched section of the Guantang Bridge in Liuzhou, Guangxi Zhuang autonomous region, was installed early on Monday morning, the bridge's builder said, calling it the most difficult part of the project.
The bridge spans 457 meters across the Liujiang River, according to Shanghai Civil Engineering Co, a subsidiary of China Railway Engineering Corp.
The middle arch, with a span of 262 meters, weighs 5,885 metric tons.
Lifting that much weight is equivalent to lifting 1,100 adult elephants at the same time, the heaviest lifting project in the world to date, the company said.
"However, it only took our operator a click of a mouse to finish the big project," said Tang Jun, chief engineer of the project.
The company said the bridge is expected to be completed by the end of this year. It will serve as a major thoroughfare between downtown Liuzhou and the city's Liudong New District.