Prediction method of main beam deflection deformation based on uneven shrinkage effect of section

Abstract

The invention discloses a section uneven shrinkage effect-based girder flexural deformation predicting method. The method comprises the following steps: I, establishment of a bridge finite element model: dividing a girder to be analyzed into N girder units, wherein the girder to be analyzed is a PC box girder; II, equivalent conversion of the section uneven shrinkage effect: respectively carrying out equivalent conversion on the section uneven shrinkage effect of each girder unit at a t moment to obtain the equivalent gradient temperature of each girder unit, wherein the equivalent conversion process comprises the selection of sections to be analyzed, the calculation of top plate shrinkage strain and bottom plate shrinkage strain and the calculation of the equivalent gradient temperature, and the equivalent gradient temperatures of N girder units form equivalent gradient temperature load information; III, loading of the model gradient temperature load; IV, obtaining of girder flexural deformation data on the basis of section uneven shrinkage. The method provided by the invention is simple in steps, reasonable in design and good in using effects; and a finite element analysis method is used to predict the girder flexural deformation by also considering the influence factors of the section uneven shrinkage, so that the prediction precision is high and the prediction is convenient to realize.

Description

technical field [0001] The invention belongs to the technical field of bridge structure design and construction, and in particular relates to a method for predicting deflection deformation of a main girder based on the uneven shrinkage effect of a section. Background technique [0002] The problem of excessive deformation of long-span prestressed concrete continuous rigid frame bridges has attracted more and more attention from scholars at home and abroad. The researchers mainly used the finite element method to predict and analyze the long-term deflection value and its development trend of continuous rigid frame bridges, but found that the predicted theoretical value was very different from the actual observation value. Not only did the accumulated deflection value of many bridges far exceed the theoretical value The calculation results show that the deflection of the bridge increases rapidly after several years of construction, and there is no sign of convergence. Therefor...

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Problems solved by technology

[0004] Currently commonly used shrinkage and creep prediction models include ACI model (model recommended in ACI 209R-82 specification), CEB-FIP (1990) model, B3 model, GL2000 model, etc. The length ratio is used to calculate the theoretical thickness of the member. In actual calculation, the effective thickness of each part of the box girder is generally averaged, and it is difficult to consider the influence of uneven shrinkage of the box girder section.

Moreover, there is currently no method that can accurately and reliably predict the uneven shrinkage effect of the box girder section, and there is no clear implementation method in the finite element predictive analysis

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