During the Song dynasty, Zhang Zeduan had painted the bustle and hustle panorama on a rainbow-like bridge, entitled “Qingming Festival on the River”. This Chinese famous scroll painting has illustrated very detailed of how strong was the connective life between the two societies that were separated by the River Bian-He. The painting depicted the scenery of the street market on a bridge during the Qing Ming Festival. People named the arched structure as the Rainbow Bridge. The influence of Rainbow Bridge on the society was important for the people from both sides. It had been playing its role as the shortcut for the people from both sides to communicate and to run their daily routines on the bridge. However, the Bian-He Rainbow Bridge disappeared later due to the fading of Bianjing. Hence, “the lost empire” is referred to the bridge on Zhang Zeduan’s painting.
Song Dynasty has been famous of its various technological inventions such as printing, paper money, porcelain, the compass and etc. One of the remarkable archeological masterpieces is of course the bridge from the mentioned painting that people has been admired for many centuries. According to historians, this arched feature is built by using timber.
The application of the technique to construct the bridge has been studied by engineers and bridge experts for many years. They are interested on how the bridge builders during the Song dynasty constructed it. The architectural establishment of the Rainbow Bridge in the Song Dynasty has impressed many experts due to its difficulty on effectively using straight logs to form the required arch. Furthermore, the interesting part of Rainbow Bridge was the method of how the straight logs were “woven” and tied together with merely the bamboo ropes. In contrast, none of the modern technology is utilizing bamboo ropes to tie the joint of members. Thus, the “woven timber structure” is termed as the technological application, since the project was done as if a delicate “craft” by weaving pattern.
Also, the interesting part about the bridge was that it stood in steadiness without any pier supports. This kind of bridge-building technique did not exist in western society. According to the concept of contemporary engineering, the basic structural elements in bridge are beams, the span, and the support members. The primary consideration in designing bridge is the safety factor and/ or the stability of the structure to withstand the compression force or the loads on the bridge. Thus the support members of the bridge should be designed carefully, and the material to be used to build arched bridge should be strong enough to withstand the compression on the bridge.
The building materials such as steel, precast concrete and reinforced concrete are the commonly used material of today. In the past, stone was recognized as a suitable material in constructing an arched shape bridge. In fact, stone had been a strong building material in Roman as many the ancient Roman arched bridges were made from stone. Nonetheless, the Song’s dynasty used timber to build the arched shape river, since the area was rich in logs.
As for the support system in the arched bridge, abutments play the roles in supporting the compressive force from the arched bridge. The Rainbow Bridge was exactly utilized this concept to distribute the applied loads to the abutments at both sides, thus, the horizontal thrust will generated from the ground to overcome the applied loads.
Technology has been existed for many centuries. Human creates technology due to the needs to solve their lives’ difficulties and obstacles, in other words, to improve the life’s standard. History has recorded many impressive technologies and creations that left by our intelligent ancestors. Their masterpieces are in diverse fields, ranging from structural, mechanical to astronomy and etc. Their inventions are important heritages for us. These heritages are now taken as the fundamental knowledge for experts to use as applications on related fields, for instances, Science and Engineering, Architectural and etc.
Hence, tracing back the knowledge and the past technology could help us to understand the similarity and the development between past and modern society. The technique of building Rainbow Bridge was thought to be a lost heritage that could never be rebuilt again. However, base on the delicate painting from Zhang Zeduan, experts get helpful information from the drawing’s detail. The bridge experts studied the bridge’s structures, in combination of the fundamental concept in structural engineering. Finally the Rainbow Bridge is re-constructed at a town located in the famous Song city of Suzhou.
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