Effective Prestress Of Prestressed Concrete Bridge In Service Evaluation And Program Development Based On Limited Testing Point

Through Finite Element Method (FEM) and based on the Computer and Bridge CAD t echnology, t he m ethod o f p redicting e xisting p restressing force o f i n-service prestressed concrete structure is put forward and its corresponding program is worked out. In this paper, Firstly the procedure of the method and program which predicting existing prestressing force with limited number of detection points are put forward to prove its feasibility.Then the program's pre-processing and post-processing are introduced. To facilitate the technician and make full use of the object-orient technique and graph technique, a convenient in-put data system is worked out using Visual Basic to complete the pre-processing of the program, which based on bridge software technology. To finish the post-processing of the program, Visual Basic is employed to fulfill the AutoCAD secondary development, which outputs computing results to AutoCAD in graph format.Next, t he p restressing force o f s tructure i s analyzed. Based o n t he analysis o f prestressing loss and effective prestress. connection of prestressing reinforcement and concrete . finite element simulation of prestressing force, the program's implementation procedures for prestressing analysis are put forward and its according algorithm is worked out. Based on the theoretical analysis of structural finite element method, the program's implementation procedures for the FEM analysis of static internal force are put forward and its according algorithm is worked out.Finally, the key part of the program is worked out, which fulfilled the functions of predicting existing prestressing force of in-service prestressed concrete bridge with limited number of detection points' strain value. Then two examples are given to check the validity of the program, of which results proved that the assumption and its structural analysis are correct the computing m ethod is feasible and the error can meet the engineering standard.