Research On Axial And Eccentric Behavior Of Tubed Steel Reinforced Concrete Stub Columns

In this thesis, experimental research and finite element analysis have beencarried out for the behavior of tubed SRC stub columns, including axial behaviorand eccentric behavior. And the bearing capacity formula was verified by the testand analysis results. The main contents are as follows:1. Six circular tubed steel reinforced concrete stub columns and six squaretubed steel reinforced concrete stub columns under axial compression were tested.The main variable parameters of specimens were the sizes of the cross section,width to thickness ratio of steel tube, welded shear connectors or not. Analysis ofthe failure modes and bearing capacity were conducted. Load-strain of specimencurves, load-horizontal transform coefficient curves and load-stress of tube curveswere obtained. The variation of tube stress along the height of specimen wasanalyzed. The results showed that circular and square SRC specimens under axialcompression occurred shear failure mode and collapse mode respectively. Whetherwelded shear connectors or not had no effect on the failure mode of the specimens,the bearing capacity and ductility.2. Six circular tubed steel reinforced concrete stub columns and six squaretubed steel reinforced concrete stub columns under eccentric load were tested,which have the same variable parameters with specimens in axial compression test.Analysis of the failure modes and bearing capacity were conducted. Load-midspanlateral deflection curves, load-stress of tube curves were obtained. The resultsshowed that circular and square SRC specimens under eccentric load occurredflexural failure mode, whether welded shear connectors or not the shape steel wasbonded well with the concrete.3. The finite element method (FEM) model for TSRC stub column wasestablished by ABAQUS. The FEM results show generally good agreement with testresults. Based on the FEM model, analysis of the influence of concrete strength,steel yield strength and ratio of steel on the axial behavior of TSRC stub columnwas conducted. Influence of eccentricity ratio on eccentric behavior of TSRC stubcolumn was analyzed. 4. Test and finite element results were compared with the bearing capacitycomputing method of TSRC stub column. The results showed that the bearingcapacity of TSRC stub column under axial compression could be calculated by theassumption that tube along the ring was completely yield. And the bearing capacityof TSRC stub column under eccentric compression could be calculated by themodified whole cross-section plastic assumption in EC4.