Study On BridgeConstruction, Maintenance, Management Of The Song And Jin (Jurchen) Dynasties

Large quantity of bridges with varieties of styles, advanced technology and abundant materials were built in Song (960-1279) and Jin(Jurchen)(1115-1234) dynasties. And this stirred up the climax of bridge construction in ancient times of China.The great development of bridge construction depends on large sum of money. The collection of the fund of bridge construction had many ways. The government investment played a key role in the ways, and most are large size bridges. There were also some individuals including government officials, merchants, monks, and also some common people, who were rich enough, participated in the construction of small size bridges. Bridges could not be built in the way of single proprietorship because government was lack of money. So fund-raising is the only way in such a situation. The advocation of government officials and the persuasion of monks had positive effect on the raising funds of bridge construction. And, of course, there were also many incidents that common people spontaneously collected money in bridge construction.The technological achievement of bridge construction in Song and Jin(Jurchen) dynasties was well-known in the world, especially in the stone girder bridge of Song and the stone arch bridge of Jin(Jurchen).Luo Yang Bridge, in period of the Northern Song, intensively adopt the technology of raft foundation, reinforcing foundation with oyster, float shipped frame beams. An Ping Bridge of the Southern Song evolved raft foundation to sleep wood sink base.Hu Du Bridge successfully accomplished the stone girder with the weight of more than two hundred tons. The sagitta-span ratio of Lu Gou Bridge of Jin(Jurchen) has been extremely approach to the optimum of design theory of modern arch bridge. And the entire stability of the bridge had been increased through piling up arch with transverse method. The inflected arch of Tian Sheng Hao Bridge effectively decrease the possibility of the jam of bridge opening. During the construction of pontoon bridge in Song and Jin(Jurchen) dynasties, it also appeared exploration and practice of model test which belongs to the modern bridge theory.The contribution of Song and Jin(Jurchen) governments in maintenance and administration of bridges was prominent. They not only set up specific institutions of bridge maintenance and administration, but also formulate relevant regulations and laws which specially and mainly administrate and maintain the important bridges.