Identification Technical Of Practical Security Of Stone Arch Bridge In The Three Gorges Reservoir Area

There are thousands of stone arch bridges on the road of counties and townships in Three Gorges reservoir area, many of them have a problem of poor carrying capacity. Therefore, making a security assesment of the bridge for the safe orperation of the bridge becomes an important problem to be settled promptly. At present, there are some major measures to evaluate bridge's safty at home and abroad,such as inverstigations based on appreance, assesments of expert's experience,analysis of level and the theory of structural reliability . However, due to financial, technical and other constraints, such measures have been limited in the security assessment of bridges in Three Gorges reservoir area. So to empolder some safe ,economic and easily popularized bridge's security assessments which avoid of complex examination and calculation to guide the stone arch bridge's security assesment in Three Gorges reservoir area are of great practical use and far-reaching significance.The four typical diseases of stone arch bridge and the damaged characteristics index of bridge's cross-section can be conclude through the research of the common disease and it's mechanism of damage. Ascertainment of permanent deformation target limits of stone arch bridge axis is through permanent deformation reflected by the torsion values of main arch axis , the allowable stress and analysis of the finite element.we can obtain the characteristic index value of cracks of the main arch according to the fracture anddamage mechanics theory and the methods of applied mathematics. We can ascertain the crack limit target by model test; we can get the characteristic index value of weathering materials and structural defect which is ascertained by the allowing stress which is to check it's bearing capacity. Hereby we can come to a conclusion that the safety criteria for the classification of level of bridge's single and typical diseases. We contrapose the diversity of bridge's disease ,analyze the interrelation of each disease , put forward the full-bridge safety evaluation formula that the most disadvantaged disease is regarded as disease-oriented and study and analyze the correction coefficient of each disease VS the leding diseases. We amend and test that above-mentioned result combined with the investigations on typical disease,which proved that the identification of practical security of stone arch bridge in Three Gorge reservoir area practical and reliable. At last ,we made the corresponding results tabulated,in order to facilitate the inquiring and determinant of bridge's security level for the grass-roots workers , to determin the security level of bridge ,to make the revelent remendiation measures and to ensure operating safety of the stone arch bridges in Three Gorges reservoir area.