CHENGDU — A 21.58-meter-long 3D-printed bridge of polymer composites has been unveiled in the southwestern Chinese city of Chengdu, according to the designer.

The 3D-printed bridge, with its widest part reaching 8 meters and highest point hitting 2.68 meters, is part of the 66.8-meter-long Liuyun Bridge, which spans Chengdu's Yimahe Park.

Instead of using concrete materials commonly seen in 3D-printed bridges, the 3D part of Liuyun is made with polymer ASA plus 20 percent glass fiber, which turns it tougher, stronger and weather-resistant, said Cheng Rui, head of China Southwest Architecture.

Cheng said the design team of China Southwest Architecture cooperated with a printing team in Shanghai, using China's largest polymer printing equipment that worked fully automatic 24 hours a day. It took 35 days to complete the 3D-printed part of the bridge, consuming 12 metric tons of materials.

"The combination of industrial-scale 3D printing with a landscape bridge demonstrates the feasibility of ultra-large 3D printing technology for future applications in both architectural landscape and industrial fields," Cheng said.