![](http://www.ecns.cn/hd/2019/10/22/39e1959fd42746039341bb4cbcc76e69.jpg)
A 3D-printed concrete bridge at 1:2 scale of the Zhaozhou Bridge-the oldest standing bridge in China -is seen at Beichen campus of Hebei University of Technology in Tianjin on Oct 21, 2019. The pedestrian bridge is a replica of Zhaozhou Bridge in Zhaoxian county in neighboring Hebei province, the oldest standing bridge in China. Built in the Sui Dynasty (581-618), it is also the world's oldest single-arch bridge, with a span of 37 meters according to Xinhua News Agency.(Photo: China News Serivce/Li Shengli)
![](http://www.ecns.cn/hd/2019/10/22/185b1ba660224fd99e515441b6156879.jpg)
A 3D-printed concrete bridge at 1:2 scale of the Zhaozhou Bridge-the oldest standing bridge in China -is seen at Beichen campus of Hebei University of Technology in Tianjin on Oct 21, 2019. The pedestrian bridge is a replica of Zhaozhou Bridge in Zhaoxian county in neighboring Hebei province, the oldest standing bridge in China. Built in the Sui Dynasty (581-618), it is also the world's oldest single-arch bridge, with a span of 37 meters according to Xinhua News Agency.(Photo: China News Serivce/Li Shengli)
![](http://www.ecns.cn/hd/2019/10/22/96946bc2f0c542e79965d030c09737bc.jpg)
A 3D-printed concrete bridge at 1:2 scale of the Zhaozhou Bridge-the oldest standing bridge in China -is seen at Beichen campus of Hebei University of Technology in Tianjin on Oct 21, 2019. The pedestrian bridge is a replica of Zhaozhou Bridge in Zhaoxian county in neighboring Hebei province, the oldest standing bridge in China. Built in the Sui Dynasty (581-618), it is also the world's oldest single-arch bridge, with a span of 37 meters according to Xinhua News Agency.(Photo: China News Serivce/Li Shengli)