Experimental and analytical investigation on the compressive behavior of double-skin steel-concrete composite tube walls

Abstract

An innovative structural wall named double-skin steel-concrete composite tube(DSCCT) wall is proposed in this paper. The proposed wall is composed of rectangular steel composite tube, in-filled concrete, external concrete and stud-tie bar connectors. Sixteen full-scaled DSCCT wall specimens and two reinforced concrete walls (RCW) specimens were tested under axial monotonic compression to investigate their load bearing capacity. Parameters included are the double-skin steel plates thickness, steel plate slenderness ratio (the distance to thickness ratio of the stud-tie bars), stud-tie bar arrangement etc. The vertical load-displacement responses of the test specimens are discussed along with their stiffness, strength, and deformation capacity. Experimental results indicate that the DSCCT specimens exhibited a fairly good bearing capacity, the external concrete, steel composite tube and in-filled concrete could work together well. The greater the thickness of the double-skin steel plate, the greater the buckling wavelength; The smaller steel plate slenderness ratio, the later the local buckling of the double-skin steel plate occurred, and the higher the bearing capacity of the DSCCT wall specimens. The displacement ductility coefficient of the DSCCT wall specimens was higher than that of RCW specimen. Considering the local buckling of the double-skin steel plates and the confinement effect of the steel composite tube on the internal concrete, a theoretical calculation formula of the axial compression bearing capacity of DSCCT wall was proposed. The proposed calculation values were in good agreement with the test values, and had higher calculation accuracy and stability in predicting the axial compression bearing capacity of DSCCT walls.