Seismic Damage Analysis Of Pc Frame Structures Considering Initial Defects Of Grouting Sleeve

In recent years,as prefabricated assembly structure meets the requirements of green sustainable development in China,it has been vigorously promoted and developed rapidly in China.However,due to the incomplete technical specifications and the uneven technical level of operators,there are many construction defects in the construction process of assembled buildings.Grouting sleeve connection,as the most important connection form of prefabricated assembly building,plays a very important role in the connection of assembly components.The influence of grouting sleeve on joint connection performance has been extensively studied.However,researchers all over the world focus on the influence factors of the peak load of grouting sleeve,reinforcement in sleeve,gro uting material,transfer mechanism of force between sleeves,failure mode of grouting sleeve,and so on.There are few studies on the initial defects of grouting sleeve.In this paper,the effect of initial defect damage of grouting sleeve on the performance of joints and integral frame structures is studied.The research contents and results are as follows:(1)Firstly,the initial defects of grouting sleeve are simulated,and the vertical connection performance of grouting sleeve is analyzed a ccording to different types of initial defects and different damage degrees of different initial defects.The simulation results show that among the three different initial defects of grouting material,eccentricity of reinforcing bar and stripping of grouting material and connecting surface between grouting material and component,the damage of grouting material to vertical connection performance of grouting sleeve is more serious.The effect of eccentric reinforcement on the performance of vertical connec tions is the weakest.The peeling area of grouting material and sleeve connection surface is the same percentage,and the effect on the vertical connection performance of grouting sleeve is significantly lower than that of the peeling of grouting material and reinforcing bar connection surface.(2)Subsequently,by simplifying the solid grouting sleeve model,the average mechanical properties of the model with initial defects of grouting sleeve are calculated.On this basis,the finite element model of beam-column joints of assembled frame is established,and the column push-pull reciprocating load is applied to the frame joints.The simulation results show that the influence of grouting sleeve with initial defects on the joint can be neglected when the joint is in the elastic stage;when the joint enters the elastic-plastic stage,with the increase of the number of damaged sleeves,the bearing capacity,stiffness and other mechanical properties of the joint decrease to a certain extent;the axial compression ratio at the top of the column has a very important influence on the joint performance.Ring.(3)Finally,an assembled frame model is established.The more grouting sleeves with initial damage defect appear in the section of all jo ints,the greater the seismic response of the structure under earthquake;the node with damage sleeve appears in the bottom,and the response and damage under earthquake are obviously higher than those of the upper joints;the damage of the section of mid-column joints has a greater impact on the seismic damage of the structure.At the edge column joint.