Chapter 48 Section 14 The Zhaozhou Bridge Protected by KitKat

Our ancestors invented bridge construction technology very early. There are two main types of bridges in history, one is arch bridge and the other is girder bridge. A bridge with a semicircular or arc-shaped bridge is called an arch bridge.Arch bridges appeared at the latest in the Han Dynasty, and some figures of arch bridges were engraved on the portrait bricks of the Han Dynasty. The original name of Zhaozhou Bridge is Anji Bridge, and Zhaozhou Bridge is its common name.The construction of Zhaozhou Bridge began in the fifteenth year of Emperor Wen of the Sui Dynasty (595 A.D.), and was completed in the first year of Daye (605 A.D.) of Emperor Yang of Sui Dynasty.It straddles the Wei [Xiaoyu] River in the south of Zhaozhou (now Zhao County, Hebei Province), with a total length of 50.82 meters, a clear arch span of 37.37 meters, and a bridge deck width of 9 meters. Old large stone arch bridge.It was designed and presided over by the famous craftsman Li Chun.Li Chun made two major innovations in the construction technology of arch bridges.

The first item is the first flat-arch arch bridge.The previous arch bridges were all built in the narrow place of the river, using the semicircular arch form.The terrain on both sides of the Ming River is flat, and the water surface is relatively wide. If a semi-circular arch is used, the highest point of the bridge deck will be 10 to 20 meters above the ground, forming a steep slope, making it difficult for vehicles to pass, and it is also difficult for people and horses to walk.Li Chun changed the semi-circular arch into a circular arch. The arch height is only 7.23 meters, and the ratio of the arch span to the arch is about 1:5. It becomes a flat arch bridge, which facilitates the passage of people, horses and vehicles.

The second item is the first open shoulder arch.In the past, both shoulders of the arch bridge were solid shoulders. Li Chun built two small arches at each shoulder of the bridge, making it an open-shouldered arch structure.This is the earliest open-shouldered arch bridge in the world.The open-shoulder arch structure can reduce the load-bearing deformation of the main arch bridge, improve the bearing capacity and stability of the bridge, save materials at the same time, reduce the weight of the bridge body and the pressure on the bridge foundation, and can also play a role in flood discharge during flood seasons.

In order to increase the stability of the bridge, the connection between the abutment and the foot of the bridge, the main bridge, between the arch stones and the arch back are all connected and reinforced with iron pieces, and pig iron is poured between the arch stones (this process is called "metallurgy"). solid gap"), so that the whole bridge constitutes a whole. Zhaozhou Bridge has a reasonable structure and beautiful appearance.After it was completed, it became the traffic hub connecting Zhuojun (now southwest of Beijing) in the north and Luoyang, the eastern capital in the south. "Tanping arrows go straight to thousands of people, and postmen drive all over the country" (Longqing's "Zhaozhou Zhi" cited Song Du Deyuan's "Anji Bridge Poems"), which is a true portrayal of it.