Characteristics of ancient bucket arch bridge in China

If a surface that can bear the upper powder pressure without transferring the pressure to the lower powder is formed in the powder layer in the container, this surface is called an arch bridge. The arch bridge is upward convex, and its maximum principal stress acts along the arch bridge surface, while the minimum principal stress along the vertical direction of the arch bridge is zero. The formation and disintegration of arch bridge may occur repeatedly in the process of powder outflow under the action of gravity, which is called moving arch bridge.

The arch bridge in China is unique. The beauty of form is rare in the world. There are steep arches with humps, flat arches like bright moons, flat perforated arch bridges with jade belts fluttering, and long arch bridges with natural longitudinal slopes. There are open arches (for example, adding a small arch to a large arch, now called an open-web arch) and closed arches (now called a solid-web arch). Arches are semi-circular, polygonal, arc-shaped, oval, parabolic, egg-shaped, horseshoe-shaped, pointed arch, and so on.

There are single holes and multiple holes in the number of holes, and odd holes are more than even holes. If the main arch of a hole is loaded, the load can be transferred from near to far to the main arch of other holes through the deformation of pier or the action of structure on the arch. This kind of arch bridge is called continuous arch bridge, or multi-arch for short. The three-hole, five-hole, seven-hole and nine-hole stone arch bridges in Jiangsu and Zhejiang water towns generally have the largest middle hole, and the diameters on both sides decrease in proportion. The piers are thin and light, and the pattern is unified, which is admirable.