million bridges existed in China in the 1920s, with as many as fifty-two bridges per square kilometer in some areas of the water-laced Jiangnan region (1937: 33).
Marco Polo himself noted the seeming ubiquity of bridges in Quinsai or Hangzhou, numbering, he said, some 12,000 bridges, an exaggerated figure that might have been inflated by a copyist.
In China, as in other countries, bridges figure not only in legends and myths but are also detailed as part of the material achievements of emperors down through the ages. It is said that the Sage Emperor Yu at the beginning of the third millennium BC summoned giant turtles to position themselves in a river as a means for him to cross. Early bridge builders, recognizing this precursor technique, used a continuous but broken line of large stones to accomplish the same purpose, forming “turtle bridges,” a type one can still see in shallow streams throughout the countryside.
As early as the twelfth century BCE, Shang dynasty texts began to employ the contemporary Chinese characters for bridge, qiao and liang, both of which include the wood radical, explicitly revealing that wood was a common building material for early bridges. Probably simple logs laid side by side rather than hewn timbers were placed across narrow streams or ditches surrounding settlements, as can be seen in the 7000 BP Neolithic Banpo site near contemporary Xi’an. Limited only by the height of available trees, spans were probably lengthened by using “turtle bridges” as piers. Even today in remote mountain areas, it is possible to see somewhat primitive piers built up of stones securely held in cages made of woven bamboo. It is not clear when either wooden or mortared stone piers began to be used to lengthen an effective span.
Along this garden path in a back area beyond Du Fu’s cottage in Chengdu, Sichuan, these step-on blocks have been molded to appear like lotus leaves.
Step-on Block Bridges
Unlike bridges that span open space in order to allow passage from bank to bank, block stone “bridges” actually take shape through sinking cut stones along a line within a streambed. Their precursor form often was simply a procession of large stones thrown into the water so that a walker could traverse the stream without getting wet. Most step-on stone block bridges or dingbu, as they are called in Chinese, comprise a single line of stones, some in their natural form while others have been chiseled into a shape. One of the most elaborate of these stepping-stone links is the 133-meter-long one at Renyang town in the southern part of Taishun county in Zhejiang. With 233 blocks, the passageway has the appearance of piano keys, with one set made of white granite placed higher, while the other lower set is made of darker bluestone. Passersby can step aside so that others may easily go by without slowing their gait, something necessary where heavy loads may be carried on a shoulder pole. Block stone “bridges” are a low-cost response to a critical need for dry passage across a stream. Rarely does floodwater destroy a line of stones of this type, and any movement is relatively easy to repair. Countless others of this type can be seen in the mountains throughout southern China.
Irregularly shaped stones collected from a nearby gorge are set into the streambed in an alternating pattern so that one foot of a pedestrian can easily follow another. Likeng village, Wuyuan county, Jiangxi.
Suspension Bridges
The longest and most sophisticated bridges in the world today are suspension bridges, with a lightness that far surpasses any bridge utilizing beams or arches to span space. China, which is a world leader in the design and construction of modern suspension bridges, has a long and continuing history. Early forms were relatively primitive ropes, hanging as a catenary curve, that were fastened to trees or anchored to stone counterweights on both ends. Pedestrians then could grasp or slide along the cables. In some areas, parallel ropes, held taut at different elevations, made it possible for walkers to tread on one rope while maintaining balance with the other, much like a tentatively supported tight-rope walker. Still other suspension bridges involved multiple cables fitted with cradles or baskets into which human beings, animals, or goods could be strapped and then swept across. Over time, suspension bridges evolved to include also a deck covered with wooden cross-planks. It is this last type, with suspended decking and at varying scales, that continues to be seen widely in the dissected mountainous areas of China. While suspension bridges have an inherent predisposition to sway, undulating in wave-like motions, they nonetheless provide an economical method of linking one side of a valley with the other.
Suspension bridges throughout the mountainous areas of southwestern China are made of thin wire “ropes.” The bed of the bridge, which is leveled with rough-hewn timber boards, follows the downward and upward arc of the load-bearing “ropes.” Additional “ropes” are used to lift the base “ropes” to prevent excessive sagging and to provide hand-holds for those crossing the swaying span. Anxian, Sichuan.
Villagers in mountain areas of Yunnan, as shown here, as well as those in eastern Tibet, traditionally fashioned narrow suspension bridges by fastening ropes made of rattan, a climbing palm with tough stems, to trees on both sides of a gorge.
Built in 1629 to span a ravine some 10 meters above the roaring Beipan River in Guizhou, this 50-meter-long suspension bridge was assembled from iron links coupled together into sets of parallel chains. The woodblock print highlights the number of temples and pagodas that populate the area at the rear of the bridge. A statue of Buddha is in the foreground.
With diminished mass, the grace of a suspension bridge arises from the lines that give it strength—plaited cables fashioned from bamboo, rattan, or other materials of vegetable origin. Marco Polo observed the making of “bamboo rope”: “They have canes of the length of fifteen paces, which they split, in their whole length, into very thin pieces, and these, by twisting them together, they form into ropes three hundred paces long. So skillfully are they manufactured, that they are equal in strength to ropes made of hemp.”
Although braided metal threads are common in fashioning cables today, iron chains were actually used in China as early as 206 BCE, an innovation that did not appear in Europe until 1741 and in North America until 1796. Among the most notable iron chain suspension bridges is the 113-meter-long Jihong (Rainbow in the Clear Sky) Suspension Bridge in Yunnan, which spans a gorge of the Lancang River and is said to have been crossed by Marco Polo. The bridge seen today was built in 1470. Some suspension bridges, like the Anlan (Tranquil Ripples) Bridge in Sichuan, discussed on pages 156–9, are composed of multiple spans supported by granite in order to overcome the sagging in a span of 300 meters. While cables once were made of braided bamboo, for the past thirty years they have been made of heavy-duty steel wires.
This unusual shigandang (Stone dares to resist evil) totem, with its colorful menacing face, is situated near the head of the suspension bridge to provide protection for the nearby village by preventing harmful influences from crossing the bridge. Anxian, Sichuan.
The dozen wrought iron cables and links which constitute the base of this suspension bridge, are anchored into the cement abutments sunken into the earth on both ends of the bridge. Anxian, Sichuan.
Beam
