The Prestress Evaluation Based On Concrete Beam Crack Characteristics Parameters

Prestressed technique has been widely used in the construction of bridge structures.However, due to deficiencies in the management of design, engineering construction,operation management, and the rapid development of prestressed concrete bridge, a largenumber of bridge diseases appear, which directly affects the safety, durability and service lifeof bridges. This paper aims at existing cracking problem of prestressed concrete bridge, isbased on the measured parameters of actural bridge crack, and evaluates the effectiveprestress of prestressed concrete after cracking.Main research contents of this paper are as follows:First, this paper proposes the analysis method of effective prestress for rectangular,t-shaped, box-shaped in presstressed concrete. While in a given concrete compression zoneheight, the effective prestress of a cross section can be calculated, and provides a theoreticalbasis on evaluating of effective prestress in a bridge.Next, the paper is based on section analysis, and provides analysis method of effectiveprestress computation of longitudinal distribution. Taking a study of prestressed concrete tbeam as an example, the paper establishes statistical parameters of fracture distribution atdifferent load levels, and gets the effective prestress of beam through an analyticalcomputation method.Finally, through a prestressed concrete box girder working as relying engineering, thepaper calculates the concrete compression zone height and effective prestress in the conditionof different levels of tension control cases, and compares with the effective prestress of actualcrack conditions.