Strengthening Of RC Columns And Performences Of Strengthened RC Columns

According to the Prospect of Investment Analysis Report on Strengthening Industry of 2015-2020,there are a large number of buildings needed to be strengthened because over the design period,and about 1/3 of residential safety stocks are inadequate,the residential structure is gradually aging too.In addition,due to the rapid construction speed and large building base,it is inevitable that a variety of housing structures will be urgently damaged as a result of structural damage in the process.In practical engineerings,it is still rare to see studies on the strengthening of damaged members by means of finite element simulation;strengthening schemes formulated in domestic engineerings are still depending on experience at present,and studies on the quantitative optimization using the finite element software are rare.In this paper,the quantitative optimization work on two strengthening schemes(i.e.Increasing Section Area Strengthening method and Externally Wrapped SteelSection Strengthening method)using for strengthening the damage columns on different positions(i.e.corner,middle,side)is done through an engineering example to provide a certain reference for similar strengthening engineering projects.Firstly,The failure phenomenon and failure mechanism of RC columns in different positions such as corner,middle,side in the building are not quite different.And the thought of classification and strengthening considering the different characteristics of different positions is proposed.Secondly,through the comparison of the advantages and disadvantages of strengthening methods,Increasing Section Area Strengthening method and Externally Wrapped Steel Section Strengthening method are applied to optimize in this paper.And specific plan is designed by PKPM module of the damaged column engineering cases afterwards.Then,9 models about corner,middle,side damaged RC columns are set up by ABAQUS.Then the realistic conditions that the column may suffer in real are simulated through three ways of loading style that are Displacement,Force and Horizontal cyclic force loading.The force characteristics of columns in different positions are distinguished by different Reference Point.RF-U curve,concrete column equivalent plastic strain(PEEQ)images,the equivalent stress(MISES)images and hysteresis curve are obtained in these three loading mode to analyze the ultimate bearing capacity,deformation properties and seismic performance of the two kinds of strengthening methods.The overall result is:1)The method of Increasing Section Area Strengthening and the method of Externally Wrapped Steel Section Strengthening can both greatly improve the ultimate bearing capacity,resist deformation and seismic performance of strengthened concrete columns,and the enhancing range is different in each way.2)The Increasing Section Area Strengthening Method can increase the ultimate bearing capacity and the ability to resist deformation in these three types of columns more than the Externally Wrapped Steel Section Strengthening Method.Especially,the capacity of ultimate bearing capacity is more than 2 times higher than that of the Externally Wrapped Steel Section Strengthening columns.3)For the middle columns,Increasing Section Area Strengthening columns are better than the Externally Wrapped Steel Section Strengthening columns under different loading styles.This conclusion can be trusted because that it is consistent with the actual engineerings.4)For the edge and corner columns,Increasing Section Area Strengthening columns and the Externally Wrapped Steel Section Strengthening columns have different advantages and disadvantages,but the latter is better if the seismic performance is primarily considered.