Anji Bridge

Architecture
Stone

• The Zhaozhou Bridge, poised over the Xiao River near Zhao County in Hebei Province, stands as a testament to ancient engineering as the world's oldest surviving stone arch bridge. Completed circa 605 AD during the Sui Dynasty's Daye era, it boasts a rich history that spans over 1,400 years.
• Its architectural prowess is evident in the innovative use of "waist irons," two sets of iron clamps which are externally riveted to connect the stones along the bridge's main arch. In the arch's slimmer parts, these iron ties are riveted to the rear of the stones, enhancing the arch's structural integrity and tensile resistance, and ensuring its longevity against tension-induced strains.

Figure (1): Shijiazhuang Municipal People's Government Website
Figure (2): Liang Sicheng surveying and mapping the Zhaozhou Bridge, 1933 (Image data from the collection of the China Building Society Memorial Hall, China Building Society)