Cracks Mechanics And Solution Analysing Of Long Span PC Continuous Rigid Frame Bridges

With the quickly development of our bridge construction, we have built more more and more long span prestressed concrete continuous rigid frame bridges in our country.However,crack and excess deflection of rigid frame bridges became a serious problems.This dissertation takes the example of Secondary Channel Bridge of Humen Bridge,a 270m long prestressed concrete box-girder continuous rigid frame bridge,adopt the method of Finite Element Analysis (FEA) method to analyse the stress features of this bridge.Mian research works of this dissertation are included below:(1)Make a review of development and researches about long span prestressed concrete continuous rigid frame bridges in China and abroad, calculation means of crack and deflection.(2)Mechianics and cause of crack and deflection.Analyse the dates of cracking investigation about prestressed concrete box-girders bridges in Guangdong, Zhejiang,etc, provide a statistics features of the cracks. Take the example of a rigid frame bridge, analying the contribution to box-girder stress from temperature effect, shrinkage and creep, three-dimensional PC, temperature difference of webs.(3)By the method of FEA, a structural analysis is made about the Secondary Channel Bridge of Humen Bridge, a 270m long prestressed concrete box-girder continuous rigid frame bridge. This bridge took a series of advanced design and construction methods to control cracks and deflection.Through the FEA, the merits and shortcoming of this bridge are pointed out, and generalize the experiene of prevent crack and deflection.(4)Introduce the development and researches of construction monitoring and health monitoring about long span continuous bridges in China and abroad.(5)Provide the treating ways to reduce crack and deflection of long span prestressed concrete continuous rigid frame bridges,from the factors of design,constructing,and operatiion monitoring,etc.