Identification method of prestress loss in prestressed concrete frame structure

Abstract

The invention discloses a method for identifying prestress loss in a prestressed concrete frame structure, which includes selecting the set position of the beam in the prestressed concrete frame structure as the displacement monitoring point; using the initial displacement value calculated by the finite element model and the occurrence of prestressed tendon The displacement value of the unit prestress loss is set to construct the displacement influence matrix of the prestress loss; the displacement change value at the displacement monitoring point is collected when the prestress loss occurs in the structure, and the displacement change value of the displacement monitoring point is integrated into a displacement change matrix; The displacement change matrix and the prestress loss displacement influence matrix are used to construct the calculation model of the prestress loss identification matrix; the least square method is used to construct the auxiliary function for solving the prestress loss identification matrix, and the minimum value of the auxiliary function is calculated by MATLAB to obtain the prestress loss identification matrix; The unit prestress loss amount and the loss identification coefficient of each prestressed tendon in the prestressed loss identification matrix are used to calculate the prestressed loss degree of each prestressed steel bar.

Description

technical field [0001] The invention relates to the technical field of civil engineering, in particular to a method for identifying prestress loss in a prestressed concrete frame structure. Background technique [0002] Since the birth of prestressed concrete structures in the 19th century, they have been widely used in long-span structures such as bridges and buildings because of their ability to control structural deflection and cracks. However, due to the influence of factors such as construction technology, concrete shrinkage and creep, and reinforcement stress relaxation, prestressed concrete structures inevitably suffer from prestress loss, and even sudden accidents due to excessive prestress loss. [0003] In view of the loss of prestress, my country's current "Code for the Design of Concrete Structures" (GB50010-2010) puts forward six calculation formulas for the loss of prestress, which are the deformation of the anchorage at the tension end, the shrinkage of the pr...

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Problems solved by technology

[0004] However, some of the above factors have mutual influence, such as the prestress loss caused by concrete shrinkage and creep and the prestress loss caused by the stress relaxation of steel bars, the method of calculating separately and then superimposing is not perfect; The effect of structural fatigue caused by reciprocating action on the prestress loss of the structure has also attracted widespread attention from scholars, but it is still in the preliminary stage of research, and it is not yet possible to perform theoretical calculations on the prestress loss caused by fatigue

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