Research On Elastoplastic Mechanical Properties Of RC Piers And Method Of Earthquake Resistance Reinforcement

Earthquake damage showed that a large number of serious damage and even collapse of the bridge are due to inadequate seismic performance of bridge pier, which provided with poor ductility and energy dissipation. Therefore, it is important to in-depth study and understand of the plastic nature of concrete piers, and carry out the research on methods of seismic strengthening.PUFA(the material composed of polyurethane and fly ash) is a new environmentally friendly polyurethane composite material. It possesses the characteristics of high strength, high tensile strength, toughness and economical environmental protection. In this paper, we proposes a new method of seismic strengthening- the use of its pier for seismic retrofit of reinforced concrete methods,and used the finite element method to the study the seismic of the reinforced piers.The main content of this article contains:Firsrtly, built the fiber model of reinforced concrete pier by using nonlinear beam-column element in OpenSees;built the entities model of pier by using damaged plasticity model in ABAQUS to simulate concrete.By comparing the result of analysis and experiment, proved the effectiveness of the two models, while provided the basis for the study and analysis of seismic strengthening.Secondly, completed a series of mechanical properties experimental research.Through the mathematical statistics and analysis established the relationship between its compressive strength and density, flexural strength and density, elastic modulus and density, moreover the relationship of stress-strain.Thirdly, used finite element software ABAQUS outsourcing for the nonlinear numerical analysis of the concrete piers outsourcing of PUFA and stirrups.Calculation results showed that the use of new methods of strengthening has greatly improved the ultimate capacity and deformation of pier, so the effect of strengthening is significantly. By studying the different parameters (volume of hoop and outsourcing thickness) on the reinforcement effect, we found that increasing the thickness of PUFA to improve the seismic performance of the pier had significant effects. Finally, we compared the new method with the method of using concrete to reinforce the approach pier, and the result showed the superiority of our method.