Chinese Bridges. Ronald G. Knapp

“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 Bridges

      On the surface, bridges constructed using beams suggest simplicity and lack of distinction, merely wooden or stone planks laid from bank to bank. While many Chinese beam bridges indeed are straightforward and rudimentary, others are surprisingly intricate, even novel. Ordinary beam bridges, supported by intermediate poles and columns as well as crosspieces, are features commonly present in the pastoral scenes of Chinese paintings, reflecting perhaps their ease of construction and ubiquity in the countryside. Substantial beam bridges made of timbers and supported by stone piers are among the earliest bridge type described in Chinese historical chronicles, with a history that reaches at least to the second millennium BCE.

      Qinshihuang, the first emperor of Qin who unified China in 221 BCE and is noted for his construction of walls and roads, also built notable beam bridges. During his reign, an imposing, multiple-span bridge—18 meters wide and some 544 meters long— was built near the Qin capital at Xianyang. Eight-meter-long timber planks were used to form each of the sixty-eight spans that rested on massive cut-stone columns sunk into the bottom of the Wei He River. During the Han dynasty that followed the Qin, at least two more large beam-type bridges and numerous smaller ones were built in the region around the flourishing imperial capital of Chang’an, just to the south of Xianyang. Several of these continued in use until the Tang dynasty, serving as important conduits along the fabled Silk Road. Piers of timber, stone, and iron as well as cylinders formed from bamboo containing rocks and earth, some dug into the muddy river bottom, supported bridges of this type. In a Han-dynasty tomb chamber, which was opened in today’s Inner Mongolia in 1971, a painted image of striking proportions of a wooden beam bridge crossing the Wei He River was revealed. Using rather slim stone columns