Investigations on global buckling behaviour of concrete-filled double-skinned steel tubular columns

Abstract

Concrete-Filled Double-skinned Steel Tubular columns (CFDST) are proved to possess exceptional structural resistance in case of fire and multi-hazard situations. This superior quality of CFDST makes it preferable in long column applications. However, studies on the long column behaviour of CFDST is very few, and their results are not in line with the behaviour of CFST long columns. Whereas, several researches on stub column CFDST shows that, the axial compression behaviour of CFDST is similar to CFST. In this paper, selected results (4 numbers of circular CFDST specimens) from a large test data is presented. Axial compression behaviour of long column CFDST specimens is studied, with non-dimensional slenderness λ around 1.0, and hollowness ratio as the governing parameter for study. Test results namely, axial load carrying capacity, axial deformation and lateral deflection are presented in this paper. Numerical models are also developed and validated with the experimental results, to carry out more parametric studies. Further, the experimental axial capacity values are compared with modified capacity equations from EC4 and AISC. Results show that extended EC4 and AISC equations gives conservative predictions for CFDST column even in the long column range. Moreover, the initial imperfections in the specimen and their corresponding boundary conditions for load application, are found to be governing parameters in long column buckling study.

Structural Performance of Strengthening of High-Performance Geopolymer Concrete Columns Utilizing Different Confinement Materials: Experimental and Numerical Study

“…The presence of ultra-high-strength concrete inside the column helps to delay or prevent buckling of the outer steel tube, while the outer steel tube effectively confines the concrete core. Columns with double concrete-filled tubes offer enhanced fire resistance compared to single concrete-filled tube columns, as the outer steel tube and shell concrete protect the inner steel tube [39][40][41][42]. These double-filled columns have attracted considerable attention in the form of experimental and numerical studies due to their advantageous engineering properties [43,44].…”

Compression Behavior of Hybrid Tubes for Lightweight Steel Structures

“…There are other works in this field that introduce some variant in the design of hybrid elements, such as an outer and inner tube made of aluminum [18] or stainless steel [19], different cross sections (CHS-RHS) in the two metallic tubes that make up the same hybrid element [20], and elements designed with a slight taper [21] that allow conclusions about the effect of the inclination angle; others focus on the slenderness of the elements [22,23]. Likewise, other works [24,25] have studied the effect of the core on different grades of concrete strength.…”