Study On Seismic Behavior Of Assembled RC Columns And Frame Structures With Grouting Defects

At present prefabricated concrete structure has become one of the important directions of the development of China’s building structure.It is not only in line with the green and environment-friendly buildings advocated by the state,but also conducive to improving construction efficiency.In practical engineering,the connection of quelling grouting can not only guarantee the design quality of assembly nodes,but also match the bearing capacity of cast-in-place structure,which is the main connection mode.At the same time,there are some construction defects in the grouting sleeve connection,such as the grouting inside the sleeve is not dense,which will seriously affect the safety of the engineering structure.For this reason,relevant personnel used experimental means to carry out a preliminary study on the assembled concrete structure with grouting defects.Tests have shown that grouting defects will lead to different degrees of decline in the bearing capacity,deformation performance and stiffness of the specimens.However,the influence of grouting defects in different positions on the seismic performance of the column is not considered.In addition,the research on the influence of grouting defects on the seismic performance of the overall frame is lack.Based on this,this paper carried out corresponding research on this issue,and the main work completed is as follows:(1)This article adopts the method of binding the MPC,the existing presents a case of grouting defects by truncation reinforcement design assumptions,in order to simulate casing grouting defects caused by steel bar connection fails,and use the relevant literature in the column and the framework of the test results to validate the method,compared with the original model and simulation model of hysteretic curve and related parameters,the results show that the method is feasible.(2)The seismic performance of the assembled RC column under the action of reciprocating thrust is studied.Hysteresis analysis is carried out through the secondary development port call subroutine of ABAQUS to consider the seismic performance of the assembled concrete column with different quantities and positions of grouting defects.The results show that:the number and distribution of grouting defects will have a great degree of adverse impact on the seismic performance of the column,when the section of the column under tension or compression side of the steel bar connection is defective.Considering the replacement of equal strength,the seismic performance of the structure is basically equivalent to that of the original structure.(3)Finally,hysteresis analysis is carried out on the assembled RC frame structure,and the results show that the seismic performance of the frame decreases greatly when grouting defects exist in the column reinforcement connection-Compared with the case that only the side column has grouting defects,the frame structure with both side column and middle column has worse seismic performance,and the energy dissipation capacity of the most unfavorable case is only 62.9%of that of the intact frame.