Combined Plate-Beam Unit Analysis for Orthotropic Bridge Decks
Solution Overview
Problem
Existing methods for analyzing the mechanical properties of orthotropic steel bridge decks, particularly those with trapezoidal ribs, often lead to deviations due to simplifications, and lack accuracy in accounting for residual stresses and complex stress distributions.
Innovation Solution
A combined plate-beam unit analysis method that discretizes the orthotropic steel bridge deck into a flat shell unit for the top plate and plate-beam units for the trapezoidal ribs, considering residual stress self-balancing conditions and stress-strain relationships to achieve high calculation accuracy and reduced freedom in structural analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the stiffening ribs are analyzed according to stiffness equivalence or treated as conventional rectangular sections, then the analysis process is simplified, but the research results deviate from the actual situation due to the complex stress distribution and large number of plates in trapezoidal rib orthotropic steel bridge decks
Solution Approach 1:
The patent segments the trapezoidal rib into multiple plate components (web plates, flange plates, etc.) and analyzes each plate separately using plate theory, rather than treating the entire rib as a single conventional beam section. This segmentation allows accurate capture of complex stress distributions in each plate while maintaining systematic analysis through assembly of individual plate results.
Solution Approach 2:
The patent applies different analysis approaches to different parts of the structure: plate theory is used for the plate components of the trapezoidal rib to capture local stress distributions, while beam theory is applied to the overall rib behavior. This local quality approach ensures that each component is analyzed with the most appropriate method for its specific stress state.
2Measurement precision
If the finite unit analysis method is used to overcome the shortcomings of stiffness equivalence, then accurate and effective quantitative research on mechanical properties is achieved, but the calculation freedom increases and computational complexity rises
Solution Approach 1:
The patent merges plate theory and beam theory into a unified combined plate-beam unit analysis framework. The trapezoidal rib is modeled as an assembly of plate elements that collectively exhibit beam-like behavior, combining the advantages of both approaches while reducing computational complexity compared to full finite element analysis.
Solution Approach 2:
The combined plate-beam unit serves multiple functions: it analyzes local plate stresses, captures overall rib bending behavior, and accounts for interaction between plates and the bridge deck. This multi-functionality reduces the need for separate analysis methods and simplifies the overall computational process.
3Reliability
If welding residual stress is considered in the analysis, then the initial deformation and stress distribution are more accurately captured, but the calculation complexity and computational resources required increase
Solution Approach 1:
The patent calculates welding residual stresses and initial deformations as preliminary results before performing the main structural analysis. The residual stress distribution is determined based on welding sequences and thermal cycles, and these preliminary results are then used as initial conditions in the combined plate-beam unit analysis, separating the complexity into manageable stages.
Data Source
AI summary
A combined plate-beam unit analysis method considering a residual stress effect of an orthotropic plate, which is used for analyzing an orthotropic steel bridge deck welded by a top plate of a bridge deck and a trapezoidal rib, the top plate of the bridge deck is analyzed by a flat shell unit, while each sub-plate forming a trapezoidal rib is analyzed by a plate-beam unit. The welding residual stress of a top plate and a trapezoidal rib is obtained by a residual stress self-balancing condition, and the initial deformation of a top plate and left and right web plates of a trapezoidal rib is obtained by the stress-strain relationship. The combined plate-beam unit analysis method has the advantages of less freedom and high calculation accuracy, so it is especially suitable for structural analysis of the trapezoidal rib orthotropic plates.