The Characteristic And Application Of Stress Wave Propagation In Prestressed Bridge

Prestressed concrete bridge is based on the tensioned systems and the grouting of tensionduct is the key process of post-tensioned bridge, which affects the safety and durability of thebridge directly. Assessment of the grouted quality have a great significance for the processcontrol of the tension duct grouting quality, eliminate the hidden dangers of the construction,and ensuring the designed service life of the bridge. The main method to detect the groutedquality of tension duct is the stress wave method. So studying the regulation of stress wavepropagation in the tension duct system is helpful for detection and analysis. The maincontents and conclusions as follow:(1) The effect of the impact parameters (impact velocity, radius, material and internaldefects) on stress wave propagation was studied. The finite element software of LS-DYNAwas used to simulate and analyze the effect of impact parameters (impact velocity, impactradius, material parameters) and internal defects (hollow radius, hollow depth) on theexcitation of the Stress Wave. The results showed that, the energy radiation ratio of stresswave can be classified into three region with the changes of initial impact velocity, anddecreases with the increases of impact radius in the general tendency. low density and highelasticity modulus of the impact sphere and the high density, low elasticity modulus of thecollision substrate provide relatively bigger energy radiation ratio of stress wave. the energyradiation ratio of stress wave increases with the increase of the diameter of the hollow andincreases with the decrease of the depth of hollow.(2) The effect of the concrete structure size, the shape of duct, and contact time on StressWave Propagation was studied. The finite element software of ANSYS was used to simulateand analyze the effect of the impact of concrete structure size, the shape of duct, and contacttime on Stress Wave Propagation. The results showed that, the thickness of concrete increasesthe difficulty to separate the longitudinal wave from transverse wave, and the lateraldimension disrupts the identification of thickness frequency. The reflected intensity increaseswith the increase of the diameter of the duct and the lateral dimension norm to incident stresswave, the wave group is changed with the difference of reflection amplitude of the P-waveand S-wave. The effective stress wave frequencies and the resolution ratios of defect decreasewith the increase of contact time.(3) The prestressed bridge detection data analysis software was developed and used. Thedata processing procedure was programmed by Labview and Matlab, Which contains readdata, analyzes data and save the data. The FEM and laboratory models with various groutedquality were established, and, the test dates of FEM models are analyze by a programmeddata processing procedure, when the grouted quality less then50%can be detect, and apply the TH-402to the laboratory model test. The results showed that, when the grouted quality is40%can be detected.In a word, this paper can be contributed to the application and analysis of the detectionof tension duct grouted quality.