Research On Mechanical Behavior Of Embedded Column Bases With Vertical Stiffeners

A new type of embedded column bases with vertical stiffeners was studied in this paper.Firstly,by comparison between the domestic and foreign main codes,a preliminary design method of stiffened column bases was presented.Secondly,quasi-static experiment on full-scale column bases designed by the preliminary design method was conducted.Experimental specimens included three embedded column bases with vertical stiffeners and four traditional embedded column bases.Thirdly,numerical simulation of test specimens by using ABAQUS was carried out to further discuss the difference in mechanical behavior between the stiffened and traditional column bases.Lastly,design method and recommendations for the practical application of the embedded column bases with vertical stiffeners was proposed.Based on the above experimental and analytical research,main conclusions can be drawn listed in the following:(1)The hysteretic curve of embedded column bases with vertical stiffeners and traditional embedded column bases are similar,the full curve shape indicating that two types of bases have good seismic performance.The embedded column bases with vertical stiffeners and reinforcement not because of the reduction of the embedded depth and reduce its seismic performance.For unreinforced embedded column base with vertical stiffeners,the embedded depth can't achieve the column completely embedding effect,and the ductility of this base is poor.The embedded column bases with vertical stiffeners can effectively reduce the embedded depth at the same time to ensure that the overall performance of the column bases.For the specimen,the embedded depth reduced about 30%than common column bases,and the economic effect is remarkable.The shear studs suffered from top to bottom gradually decreases,and mainly to improve the integrity of the connection.The stirrup stress near the top of the base is larger than the others,and the stirrups by stress decreased with the increase of embedded depth,suggested configuration strengthen encryption stirrups.The main reinforcement stress is small,playing a role of frame reinforcement,and the suggestions according to the structural reinforcement in engineering design.(2)The finite element analysis results showed a great agreement with the experimental results in the hysteretic curve,failure mode,and the force characteristics.Finite element analysis show that the setting of the vertical stiffeners can significantly reduce the steel column and foundation compressive stress of concrete surface,and increase the effective pressure between the steel column and foundation concrete area,so as to achieve the purpose of reducing the embedded depth.For the design of embedded depth,it is suggested to take the steel column confined width to bending moments and the scape width of the vertical direction.In conclusion,the embedded column base with vertical stiffeners can reduce the embedded depth of steel column dramatically while maintaining excellent capacities of ductility and energy dissipation.Moreover,the presented design method can help engineers in design of the stiffened embedded column bases for practical application.