Need. The development of roads and waterways in the imperial era (617-1644) demanded a high level of bridge building. The Chinese constructed different kinds of bridges: timber beam, cantilever timber, suspension, and masonry. In addition, they used the stone arch in many forms: semicircular, horseshoe, elliptical, and segmental.

Cantilever Type. Cantilever bridges of timber and stone existed during the early imperial period. This type of bridge is usually made with three spans: the outer two spans are anchored on the shore, while the third is projected out over the channel and supported by cantilever beams on only one side. A good example of a cantilever bridge existed at Lilin in the Hunan province. It crossed the Lu River and had piers twelve feet wide with a span between them of just over fifty-six feet.

Semicircular Arch Type. By the seventh century, stone...