ABSTRACT
The paper describes a combined numerical and experimental study of the high strength CHS steel columns under combined axial force and bending moment which material is Grade 590 centrifugal cast steel. The purpose of the research was to obtain some fundamental information about elastic-plastic behavior of the high strength CHS steel columns with small diameter-to-thickness ratio.
The experimental work consisted of 8 beam column tests under axial force and bending moment with parameters of diameter-to-thickness ratio (D/t = 10-33), the axial force ratio (n = N/Ny) and the yield ratio of material was carried out. The numerical work was carried out by ABAQUS version 5.4 using with the solid elements. It was involved 28 numerical analyses of Finite Element models simulating the specimens tested including the results of Kamba (1992).
Evaluations of the test and numerical results showed as follows: (1) the high strength CHS steel columns with D/t < 20 have some excellent characteristics without local buckling, (2) at the end of the column, it can be seen that the stress condition is the three dimensional action locally, so that the extreme fiber stress has reached to the maximum true stress, (3) the section area of compression and tension side has increased and decreased after yielding, (4) the smaller the ratio D/t and the larger the axial force ratio, the larger the maximum moment compared with the plastic moment, (5) the development of the plastic analysis results predict the maximum moment of CHS beam columns with good accuracy.
