Analysis Of Influencing Factors On The Mechanic Behavior Of Embedded Side Column Bases

There are several problems in our current domestic standards about the structural regulations of embedded side column bases,which is not defined clearly in the design methods.So in this paper,a series of analysis of the factors of embedded side column-bases has been done.First of all,referring to Chinese and foreign standards about the design method of the embedded side column bases,a trial design of the embedded side column bases was given.Secondly,a series of numerical simulation of the integral models was built by ABAQUS,the key technologies of this method were verified to be applicable.And by analyzing the destructive process of embedded side column bases under two working conditions(shear inward and outward),we can understand its working mechanism.Thirdly,based on the analysis of 50 models of embedded side column bases,parametric analysis about the embedded side column bases was carried.The main parameters are as follows:The end height ratio(the ratio of end distance to steel column section height:c/H),the ratio of the distance of U-shape bar along the base width to the surface of steel column flange to the flange width of the steel column(b/B),the ratio of the thickness of concrete protective layer along base width to steel column section height(a/H),the distance between U-shape bar along the direction of buried depth(d),and so on.Finally,based on the results of numerical simulation,some advices about the thickness of concrete protective layer of embedded column bases and the design method of U-shape bar were given.Based on the related analytical research above,main conclusions can be listed in the following:(1)The increase of the end height ratio has no effect both on the ultimate bearing capacity and breaking load,but it can improve the stiffness of the embedded side column bases and can weak the ductility of it;The bending contribution of U-shape bar decreases with the increase of the end height ratio;As long as the end height ratio is no more than 0.5,the rate of bending contribution of U shape bar can be better guaranteed;(2)It is found that the concrete that filled into steel column has a great contribution to the bending resistance of column base joint,and can not be ignored.(3)The distance of U-shape bar along the base width to the surface of steel column flange has no effect on the overall mechanical properties of the column base joint.The reason is that the large thickness of concrete protective layer has a great contribution to the bending moment contribution of embedded side column bases;The force efficiency of the outer U steel bar is inversely proportional to the distance of U-shape bar along the base width to the surface of steel column flange,and the larger the distance is,the lower the force efficiency is;As long as the b/B of upper outer layer U-shape bar has been controlled within 1(lower outer layer is 0.25),the availability of U shape bar can be better guaranteed.(4)The thickness of concrete protective layer along base width barely has effect on the overall mechanical properties of the column base joint,but it can improve the stiffness of the embedded side column base joint and can weak the ductility of it;The bending contribution of U-shape bar decreases with the increase of the a/H;As long as the a/H is no more than 0.5,the rate of bending contribution of U shape bar can be better guaranteed.(5)The distance between U-shape bar along the direction of buried depth has no effect on the overall mechanical properties of embedded side column bases on the whole process;It either barely has effect on the availability of U shape bar on the whole process.