The Research Of Seismic Performance About HPFL Strengthening Frame Joints

High Performance Ferrocement Laminate(referred to as HPFL)reinforcement method with its reinforcement effect is remarkable,easy construction,low cost,fire and high temperature,durability and anti-aging,and the original component of concrete compatibility and Good coordination,no obvious increase in cross-section,environmental performance and other comprehensive features,has achieved a more systematic research results,but with this method to strengthen the framework of the node research has not yet started.In this paper,five concrete frame joint test models with a scale ratio of 1: 2 are designed,the same axial force to test the seismic performance of frame joints.For the five specimens in the test,the specimen J0 is the comparative specimen,which is loaded directly to the damage without pre-damage.The specimen JR1 is reinforced by HPFL without directly damaged and then subjected to the loading test.Specimens JR2,JR3,JR4 are applid by low-level cyclic loading to different degrees of pre-damage,and then reinforced with HPFL to simulate the force performance and reinforcement construction of the actual situation.Through the experimental study,the numerical simulation analysis and the shear bearing capacity of the joint,the stress performance,bearing capacity,ductility,stiffness degradation and energy dissipation capacity of the frame nodes are deduced.The main achievements are as follows:1.Based on the quasi-static test of the reinforced joints,it is found that the bearing capacity,crack resistance,stiffness,ductility and energy dissipation capacity of the reinforced joints with different damage levels have been greatly restored,The original test pieces.According to the performance of bearing capacity,ductility,energy dissipation capacity and failure mode,this paper makes a careful observation of the whole process of each specimen from the beginning force to the final failure,and analyzes the causes of various phenomena in the experiment.2.It is found that the greater the degree of damage of the specimen,the smaller the ultimate load and the limit displacement is,and the degree of structural ductility is gradually reduced by comparing thereinforcement effect of the specimen with different damage degree.After the reinforcement of the specimen hysteresis loop more full,the energy consumption of the specimen also has a certain increase.The smaller the degree of pre-damage of the specimen,the faster the degradation.After the specimen is yielded,the stiffness degeneration of each specimen tends to be gentle and the stiffness degradation tends to be consistent.The reinforced concrete frame joints are more stable than the bearing capacity and plastic deformation ability of the undeveloped frame joints,and the bearing capacity is also slower than the bearing capacity of the undeveloped frame joints.3.The simulation results show that the simulation results are in good agreement with the experimental results,and the reliability of the test results and simulation results are verified to some extent by ANSYS finite element analysis software.4.Through the experimental study and the reinforcement process of the specimen,the method of strengthening the HPFL is put forward,and the construction process of the RC frame node with HPFL is summarized,which can provide some reference for the subsequent engineering and technical personnel.5.After analyzing the shear mechanism of the core area of the node,the formula of shear bearing capacity of HPFL reinforced frame joints is deduced.The formulas are compared with the experimental results,and the rationality of the formula is verified.The influence factors of the bearing capacity of the core area are analyzed,which can be used as a reference for the followers.