Survey On CFST Arch Bridges And Research On Their Void Problem

This article collects statistics of concrete-filled steel tube (CFST) arch bridge and researches a large number of Information about the construction trend, technical level and problems in our country. After investigation I find the core concret’s separation is a special and widespread problem. It is the hidden danger of the massive construction of CFST arch bridge, it iseageriy needed to be further researched and solved. This paper also collects the theory and design practice of the CFST arch bridge in many countries, which include the constitutive relationship, interaction, analysis and calculation of the ultimate bearing capacity theory and so on. I find that there is unified cognition but no accepted results about the void. Most of the researches on the cause of void are qualitative analysis, researches on the effects of void are bearing capacity calculation, researches on the countermeasure of void are slowly.Based on above situation, I select the problem of the core concret’s separation as the object of this study. Firstly, I distinguish between the first class void and the second class void according to the resulting shape, the cause and the effects.and defined the first class void as the void that caused by the interfacial debonding,the second class void as the void that caused by the I ess dense concrete.secondl y. I n the researches of the cause of f ormati on, I quantitatively calculates the the first das void’s procession that caused by the axial pressure, hydration heat shrink.sunshine temperature difference and contraction applicate the spatial elastic increment theory and the space heat transfer theory. I analysis the second dass void from the aspects of material sdence, structure and technology. In the researches of effects, I comparise and analysis three kinds of drcumstances which is only under the action of the first dass void, only under the action of the second dass void and both under the action of the first and the second dass void. Put forward a method that the results of numerical calculation guides the finite element calculation. I n the countermeasure, I descripe and judge the detection method, repair method and prevention method.