Shown in this painting by a European is a somewhat fanciful bridge with billowing ornamentation above it that was clearly built so that large vessels, shown in the foreground, could pass easily beneath its soaring arch.
The Wanxian Bridge in Sichuan was photographed at the end of the nineteenth century by Isabella L. Bird, who stated: ”I have never seen so beautiful a bridge as the lofty, single stone arch, with a house at the highest part, which spans the river bed, and which seems to spring out of the rock without any visible abutments” (1900: 47)
The Dongshuang (East Paired) Bridge, perhaps built during the Song dynasty in Shaoxing, Zhejiang, is considered one of the finest single-arch extant bridges. Its mate, the Xishuang (West Paired) Bridge, no longer exists.
Stone Arch Bridges
In southern China, single- and multiple-arch bridges often rise precipitously above narrow canals, while others lay close to the water, with a continuous pattern of repeating arches from bank to bank, a form that is also common in northern China. Among the earliest representations of stone arch bridges are those of the Eastern Han period (CE 25–220) inscribed on fired brick tiles that have been excavated from underground tombs—themselves often constructed with arch ceilings—throughout northern China. In Henan province, a brick reveals an unadorned curved span being crossed by pedestrians, a mounted horse, and a carriage drawn by four horses with boats and fish beneath. The steep approaches are apparent, reinforced by the presence of muscular men towing the carriage up the deck, with others controlling the carriage as it descends.
The arch is a shape that carries its load outward as a result of compression that produces horizontal outward thrusts towards the bridge’s abutments. In spite of the durability of stone, moreover, Chinese stone arch bridges reveal a remarkable plasticity, a “resisting by yielding,” according to Chinese bridge builders. Throughout the Jiangnan region, where sandy soil made it difficult to sink solid foundations, bridge builders learned to make use of vertical sheer walls of stone slabs to receive those forces that might tend to deform the arch. The Chinese rarely used mortar as a bond between stones. Rather, stones were generally carefully shaped and sometimes mortised into each other or joined together by overlapping iron cramps. As a result of these techniques and the ensuing elasticity of the stone shell, stone arch bridges could tolerate a high degree of deformation without the bridge collapsing.
Located on a canal to the southwest of Suzhou in the small town of Mudu, this triple-arch span had a roofed structure on it that served to collect tolls from pedestrians who crossed the bridge.
At the end of the nineteenth century, countless arch bridges such as this one with its moon-shaped reflection, were found throughout the Jiangnan region around Suzhou.
One of China’s most beautiful arch bridges is the Taiping (Heavenly Peace) Bridge along the canal between Hangzhou and Ningbo to the west of the city of Shaoxing, Zhejiang. Built first in 1620 and then again in 1858, it is well known for its exquisite carved balustrades.
The lofty Wumen (Wu Gate) Bridge in Suzhou, Jiangsu, is located along the Grand Canal near the important Pan Gate. Said to date to the Song dynasty, it was rebuilt in the middle of the nineteenth century to a length of 63 meters.
Chinese stonecutters clearly accumulated experience that led logically to the development of different styles of bridges. Relatively crude semicircular single-arch spans can be seen in many areas of southern China, some of which are quite old. Many, however, are of more recent origin, the handiwork of local artisans who gather stones from nearby streambeds in order to fashion serviceable work-aday bridges as others did for centuries before them. Semicircular arches of dressed stone dot the Chinese landscape in large numbers. Descriptive names such as “horse’s hoof,” “egg-shaped,” “pot bottom,” and “pointed” are suggestive of other variations of elliptical and parabolic shapes. Some arches are polygons comprised of interlocked rectangular stone beams. Arches of this type echo similar ones found in Chinese tombs as well as gates through city walls, and even the Great Wall. While permitting a greater span than simple beams, polygonal beam bridges are, however, structurally weaker than true arch bridges. On the other hand, as the number of inclined stone beam segments in a multisided polygonal bridge increases from three to as many as seven, the structure begins to function much like a true arch bridge.
In the countryside of southern Huizhou, straddling the border between today’s Anhui and Jiangxi provinces, countless old stone arch bridges still serve today’s villagers. Although this bridge has a name, Qingjin (Celebrate Gold) Bridge, no information is available on its history.
A small unnamed single-arch bridge along the canal east of Shaoxing, Zhejiang.
Many stone arch bridges are infilled with earth and have seams between the cut stone that tends to allow dust to accumulate, filling the spaces so that, in time, seeds are able to germinate. As the roots of plants grow, they then have the capacity of loosening the stone blocks, shifting them sometimes to a point where gravity brings portions of the bridge down. It is not uncommon, even today, as can be seen in many photographs, for plants of all sorts to grow out from a bridge. In colder areas, moreover, these conditions are compounded because of the freezing and thawing of water that runs into or builds up in the seams, again with the means of dislodging the stone and leading to failure of the structure.
The Zhaozhou Bridge figures prominently in woodblock print culture throughout northern China, probably because of the association with Lu Ban, the patron saint of carpenters and builders, who is said to have built the bridge. After the bridge was completed, legend says that the Eight Immortals decided to cross it in order to test its strength. Lu Ban, fearing that the bridge might not support their weight, jumped into the water beneath to prop up the span with his outstretched hands. Both the polychrome and black-and-white prints from different workshops show variations of this theme.
Segmental Arch Stone Bridges
Among the most remarkable achievements of Chinese bridge building—indeed an advancement unrivalled in the world—was the creation of a segmental arch bridge at the end of the sixth century and beginning of the seventh century. This innovation, which predated similar forms in the West by 800 years—repudiated the convention that a semicircular arch was necessary to transfer the weight of a bridge downwards to where the arch tangentially meets the pier. The celebrated Zhaozhou Bridge, China’s oldest standing bridge and the oldest open spandrel bridge in the world, seemingly flies forth from its abutments. The double pair of openings piercing both ends of the arch spandrel, which at once accentuate its lithe curvature, lighten the weight of the bridge and facilitate the diversion of flood waters by allowing them to pass through the auxiliary arches rather than pound against the spandrels.
