Analyse And Research Crack In Collapsed Arch Bridge

Along with the high-speed development of our country national economy,our countryhas been already set up numerous, big bridges and airports.They played a very importantfunction in the national economy.Increscence of the car amount will aggravate these burdensnecessarily,speed the progress that it breaks.The problem of re?ective crack has been an important researching topic in bridge field.For it, a lot of analyzing and computing results prove that great error will come into being ifwe use conventional mechanics. Specially at the tip of crack, high stress is the main factorwhich in?uences crack propagation. Fracture mechanics is an important achievement in 20century, which is widely used in many fields. If we adopt the fracture mechanics, then theproblem can be solved easily. Combining with finite element method, fracture mechanicshas been an important way to solve crack problem in bridge field at present. For re?ectivecrack under repeat function of vehicle load, new conclusion can be gained if we take stresssingularity at crack tip into account. It can be proved that the conclusion we get is close tothe fact of bridge abruption.Arch bridge has been used for its unique economy and utility,the breakage is the mostimportant factor that caused by the fatigue load not only in?uenced also did harms to thesafety and normal use of constructions.So the safety about arch bridge become importantsubject we will study.The mainly results from this paper are follows:(1)At the same coordinate we map shape of arch bridge and the stress on it by theoryof mathematic mirror,the mathematic map is a usual method that can solve the problem ofarch bridge.(2)We split the subject that stress on arch bridge into two small question,one is the firstkind of question about Griffith crack,another is to solve the KI criterion about three pointbend of sample.(3)The paper studies the first question about Griffith crack in detail and analysis thestress field at the edge of crack,while not to study the criterion about three point bend ofsample.