Time-varying Reliability Determination Method of Prestressed Concrete Box Girder Bridge

Abstract

A method for determining the time-varying reliability of prestressed concrete box girder bridges based on the stochastic finite element method. For prestressed concrete box girders that are widely used in highway bridge systems and have common early-stage diseases, by combining degenerate shell elements, material constitutive relations and The crack model simulates the nonlinear characteristics of the box girder in the cracking stage, and the embedded concrete creep, shrinkage and steel strand stress relaxation model considers the deformation, prestress loss and internal force redistribution of the box girder during its entire life, through the reinforcement The uniform corrosion model and the pitting corrosion model calculate the section loss of steel bars (steel strands) in carbonization environment and chloride ion environment respectively. Finally, through the definition of random variables, sampling, calling finite element program calculation and extracting stress and strain results, the reliability calculation of the box girder bridge is realized and used to guide the subsequent maintenance and reinforcement work.

Description

Technical field [0001] The present invention is a time -changing calculation method based on the timing reliability of a prestressed concrete box beam bridge based on the random finite element method, which is used to accurately evaluate the reliability of prestressed concrete box beam bridges under the impact of the impact of uncertaintic factors and its current variable characteristics. Background technique [0002] As one of the main forms of the upper structure of high -level highway bridges, prestressed concrete box beams have a very wide application.Affected by the change of design standards, erosion of natural conditions, earthquakes, impacts, and overload operations, many of the box beams and bridges in service have different degrees of performance degradation, and it is urgent to evaluate and maintain it.However, due to the particularity of the structure analysis of the box beams, such as the shear stagnation effect, spatial characteristics, and the non -linearity of the...

AI Technical Summary

Problems solved by technology

However, due to the particularity of structural analysis of box girders, such as shear lag effects on closed sections, spatial characteristics, nonlinearity in the cracking stage of thin-walled structures, etc., reliability assessments for prestressed concrete box girders are currently rare

The reliability analysis of existing girder bridges focuses on rectangular, I, T-shaped beams with open sections, and most of them use explicit reliability analysis methods, which make it difficult to accurately express the reliability of box girder bridges in the performance degradation stage

[0003] With the application of the finite element method in the analysis of engineering structures, people naturally link the finite element method and the reliability analysis together, thus forming the stochastic finite element method; however, since the prestressed concrete box girder bridge involves height Non-linear (such as concrete cracking), concrete creep, shrinkage, stress relaxation of steel strands and other factors, so its reliability analysis has great difficulty and particularity, the present invention aims at the above problems

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