Mesoscopic Analysis Of Damage Evolution Of The Prestressed Concrete Continuous Beam Under The Vehicle Loading

As a major invention of the nineteenth century,the prestressed reinforced concrete structures are widely used in various complex structures.Its destruction process has a very complex stress-strain relationship,the existing research on the destruction process of the beam is mostly based on the finite element method,nonhomogeneous concrete is considered as a homogeneous material,and the development direction of the crack in the test specimen is set in advance,this simplification cannot accurately simulate the whole process of damage evolution of the prestressed concrete continuous beams at the meso level.Aimed at the limitations of the indoor experiments and the finite element methods,the paper uses the discrete element method to study.The concrete material is considered as a three-phase composite heterogeneity material.The meso-scale numerical model of the material was established using the PFC^3D particle flow program,the macroscopic parameters of concrete and steel rebar are calibrated by fitting the stress-strain curve of the macro test.The influence of macroscopic parameters on the macro performance of concrete is also analyzed,such as the coefficient of friction,the parallel bond radius,and the interface angle and so on.Based on the calibrated macroscopic parameters,the macroscopic model of the concrete continuous beams is established,applying the equivalent load method to apply the prestress,the damage evolution process of the continuous beam model in mesoscopic level under the vehicle loads is simulated.The damage variable is defined,a preliminary analysis of damage is made from the mesoscopic level,the influence of some macro factors such as the axle loads and the vehicle speed on the evolution process of damage is also studied.The paper simulates the generating process of the macroscopic damage under the action of the vehicle loading,through the establishment of a mesoscopic model of the prestressed concrete continuous beam,the influence of meso level damage evolution on the macroscopic properties is obtained,and it provides a reference for the design and construction of the bridge.