When was this arch bridge built?

The answer is Xiaoshangqiao, which was built in the fourth year of Emperor Yangdi's reign (AD 584), before Zhao Zhouqiao. But the preservation is not as complete as that in Zhao Zhouqiao.

Xiaoshangqiao is by far the oldest stone arch bridge in China, located in Shangqiao Town, Yancheng District, Luohe City, Henan Province, above Xiaoshanghe River. Xiaoshangqiao was built in the fourth year of Emperor Kai of Sui Dynasty (AD 584). It is a stone arch bridge with open shoulders and flat arches. It was built in the Sui Dynasty more than 20 years earlier than Zhao Zhouqiao. On June 25th, 20001year, Xiaoshangqiao, as an ancient building in Sui Dynasty, was approved by the State Council to be included in the fifth batch of national key cultural relics protection units.

Zhao Zhouqiao, also known as Dashiqiao and Anji Bridge, is a stone arch bridge located on Wulixiao River in the south of Zhao County, Hebei Province. The designer is Li Chun, an outstanding craftsman in Sui Dynasty, who was built in Daye for six years (6 10). The large arch consists of 28 arch rings, which is a single-hole open-shouldered flat arch stone arch bridge with a length of 50.82 meters and a width of 9.8 meters at both ends. Zhao Zhouqiao is one of the oldest stone arch bridges in the world, and it is a complete long-span single-hole open-shouldered flat-arc stone arch bridge. 196 1 was listed as the first batch of national key cultural relics protection units in the State Council. Because Zhao Zhouqiao is a key cultural relic, it is easy to be damaged when it is opened to traffic, so vehicles are not allowed to pass. 199111On October 24th, Zhao Zhouqiao was awarded the milestone of international civil engineering.