What is Zhao Zhouqiao's position in the history of world bridges? Please tell me the subtlety of the design of this bridge.

Zhao Zhouqiao, also known as Anji Bridge, is the oldest complete long-span single-span open-shouldered flat arch bridge in the world. It was not until the middle of19th century that a similar open-shouldered empty ticket collision bridge appeared in Europe. 199 1 was named as "International Civil Engineering Historic Site" by American Civil Engineering Society. So far, only Zhao Zhouqiao and the Great Wall of Wan Li have been selected in China, which indicates that Anji Bridge is as famous as the Eiffel Tower, the Panama Canal and the Egyptian pyramids.

Zhao Zhouqiao is a single-hole open-shouldered flat-arc stone arch bridge. The whole bridge is made of huge granite, and 28 independent stone arches are laid side by side longitudinally, with a total length of 64.4 meters (or 50.82 meters), a width of 9 meters, a clear span of 37.02 meters and a sagittal shape of 7.23 meters. North and south across the river, the bridge deck is divided into three roads, the middle road passes, and pedestrians are left and right. There are two small arches on the shoulders at both ends of the big arch across the two banks to make the chess shoulders open, which is not only exquisite and beautiful, but also convenient to pass and reduce the resistance of running water. The arch span of the bridge is 37.47 meters, the arch radius is 27.7 meters [3], the arch height is 7.23 meters, and the flattening ratio (arch height/half span) is 0.38 (height-width ratio is 7.23/37.47 =0. 19), which is much lower than that of the semi-circular arch. In fact, the central angle of the circular section of Anji Bridge is only 84, which is slightly less than 1/4 circumference. It is basically a 1/4 circular arch bridge (flat arc circular arch bridge), and the elevation angle of the arch is 42 (nearly 45) [1]. 1/4 The ratio of arc length to span of circular arch bridge is π/(2√2)= 1. 1, and that of semi-circular arch bridge is π/2= 1.57. Under the same span, the arc length of 1/4 circular arch bridge is longer than that of semi-circular arch bridge. Therefore, the stone used for the bridge body of Anji Bridge is more than 40% less than that of the semi-circular arch bridge with the same span, which not only reduces the weight and stress of the bridge body, but also makes the slope of the bridge deck relatively gentle, which facilitates the traffic on the bridge. Because the arch span of Anji Bridge is large and the arch is high enough, it is very convenient for water ships to pass. Li Chunneng realized in the Sui Dynasty more than 65,438+0,300 years ago that the long-span arch bridge is not necessarily a semi-circular arch, so the construction of this single-hole 65,438+0/4 arch bridge structure with large span and low flattening rate is a valuable creation in architectural history.

Until the West13rd century, long-span arch bridges with a span of more than 24 meters had a flat rate of 0.70-0.83, which basically belonged to semi-circular arch bridges. For example, the Fabrizius Bridge in the first 62 years of ancient Rome, with a span of 24.8 meters, a flatness of 0.83 and an angle of 159 with the center of the circle, is basically a semicircular arch bridge. 1 187 French Saint Benezet Bridge, with a span of 33.7m and a flatness of 0.70. The earliest existing circular arch bridge in Europe is the relic of the porous bridge in Alcon's inner tower built in the 2nd century [7], with a flattening ratio of 0.5-0.6 (the aspect ratio is 0.25-0.3), but the span is very small, with the spans of the first and second arches only being 6.72m and 7.28m. Flat long-span arc arch bridges began to appear in Europe at the beginning of14th century, such as It was not until the middle of 14 century that the long-span14 circular arch bridge became popular in Europe [8]. It was not until 1345 that a long-span flat 1/4 arc arch bridge with a span of 29.9 meters and a flattening ratio of 0.37 appeared in Europe-Florence Old Bridge.

The decoration of the last part of Anji Bridge is also beautiful. The top has shaped the imaginary water-absorbing beast, and pinned the good wish that the bridge will not be damaged by water and will last for a long time. Exquisite stone carvings, various dragons, animal faces, floral ornaments, bamboo joints, etc. Carved on fences and sentries, especially dragons. The dragon is either entrenched in the game or landed in the water, unpredictable and its expression is extremely moving. The carving method is vigorous and powerful, and the artistic style is novel and bold.

Are you going to write a bridge review? Bridge students?