The Characteristics And Application Of Longitudinal And Transverse Stress Wave Of Prestressed Concrete Beam Bridge

Prestressed concrete structure has big stiffness, good anti-fatigue effect, the advantages of light weight, and can effectively control structure deflection and is widely used in modern bridge engineering. Prestressed pipe grouting quality directly affect the carrying capacity and durability of concrete bridge structures, so to test the prestressed pipe grouting quality is important step to prevent and eliminate safe hidden trouble. Prestressed structure stress wave method is the main NDT methods, the research of stress wave in the prestressed pipe structure, influence factors and the transmission characteristics of stress wave signal processing and correction results help optimize detection schemes.This paper studies the prestressed concrete bridge structure in the longitudinal and transverse stress potter, using the finite element method simulation analysis in the first place, and then the experiment test and analysis, the main purpose is through the method of stress wave recognition grouting defects in prestressed concrete structures, the main research contents and results are as follows:(1) The structure of prestressed pipe grouting longitudinal transmission stress potter and concrete strength on the influence of the stress wave. Is firstly established with ANSYS/ls-dyna finite element software pipeline structure finite element model of concrete and prestressed pipe structure finite element model, and then to solve and analyze the length and width of the pulp and road. The impact on consolidation wave velocity, and the strength of concrete on the time and amplitude of stress wave in the first wave. The results show that with the length and width of the slurry increased from 0 m to 0.2 m, consolidation wave velocity increased from 4037 m/s to 4037 m/s; Consolidation wave velocity increases with the increase of grouting road degrees; With the increase of concrete model, stress wave first wave arrival time reduced from 63.89μs to 63.89μs; Stress wave signal amplitude decreases with increase of concrete strength.(2) The research structure of prestressed pipe grouting detection of lateral reflection stress potter, and through the FRFT structure of prestressed pipe grouting defect recognition analysis. First established using finite element software ANSYS/LSDYNA grouting compactness is respectively 0%, 30%, 50%, 70%, 100% of the prestressed pipe structure finite element model, solving and analysis, using the data from the FRFT to deal with stress wave signal is calculated fractional domain amplitude ratio. The results showed that pipeline reflection wave as grouting compactness increases and decreases, and there are defects of fractional Fourier domain amplitude ratio not equal, fractional domain by stimulating points on both sides of the signal amplitude than to identify grouting defects.(3) For fractional Fourier domain amplitude than the identification methods for the structure of prestressed pipe grouting defects on the experimental model analysis of the validation. By establishing the actual model, using TH402 bridge type grouting compactness detection instrument for data collection, the experimental model of grouting road. the degree was 80%, the defect length is divided into four groups, respectively is 5 cm, to 10 cm, 15 cm, 20 cm, FRFT was carried out on the acquisition data, calculate the fractional domain amplitude ratio, the experimental test results for, on both sides of grouting imperfect of the shot point signal fractional Fourier domain amplitude ratio not equal, this is consistent with simulation results.