Preservation And Restoration Practice Exploration Of The Stone Arch Bridge Of The World Cultural Heritage Grand Canal

On June 22,2014,the grand canal was listed in the world heritage list,the history of the grand canal can be traced back to the ‘lingshui' at Qin dynasty,the long lasting history has left the grand canal a legacy of traditional stone bridges including Gongchen bridge,Guangji bridge,Guifang bridge,Longxing bridge,Dongxin bridge,Bazi bridge,Joy Yongning bridge,etc.These stone arch bridge can be categorized into single span and multiple span,the elaborate design and delicate construction technique make the bridges still have traffic function.But it is undeniable that the ancient bridge has been brought into their "old age",inevitably there are stone weathering,structural deformation and other problems need to be solved.The Joy Yongningbridge is a single-span stone arch bridge,which was built during the Qianlong period of Qing dynasty.As a remnant on the grand canal,it is one of the components of the world heritage and a representative bridge on the grand canal.It has important historical,scientific and artistic values.In the early morning of July 6,2017,due to days of heavy rain in hangzhou city,the jingang wall on the northeast side of Joy Yongning bridge collapsed.Thus,we carried out the conservation and restoration work for the ancient bridge.By collecting and sorting out the literature,this paper clarifies the age of his construction and historical evolution of the Joy Yongningbridge,and evaluates its heritage value based on the investigation and analysis of its current situation.By means of digital surveying and mapping technology,the survey and mapping of Joy Yongning bridge was carried out efficiently,and a true three-dimensional model is established for the collapse situation to retain the information of the ontology of cultural relics.Meanwhile a temporary protection scheme of Joy Yongning bridge was put forward to avoid the secondary damage.Directed to the collapse and the aforementioned survey and analysis,combining theconcept ofprotection and restoration of architectural heritage at home and abroad and through the comprehensive cognition and evaluation of the value and the present situation of Joy Yongning bridge,we put forward some reasonable ideas of protection,restoration and determined the corresponding protection and restoration principles and then offered a protection scheme acceptable for all the group,and then the research on restoration measures and technology is followed.As a water conservancy engineering legacy on the grand canal,the research and engineering practice of the protection and restoration project of the Joy Yongning bridge will help to dig up the scientific value of the ancient bridge deeply,to study its structure and construction technology,to raise the public's understanding of the heritage value of stone arch bridge,and to enhance the awareness of cultural heritage protection.At the same time,it also provides an important reference for the protection and restoration of the existing stone arch bridges on the grand canal.