Experimental and numerical studies of axially loaded square concrete‐encased concrete‐filled large‐diameter steel tubular short columns

Abstract

This article presents experimental and numerical studies on the axial compressive behavior of square concrete‐encased concrete‐filled steel tubular (CECFST) short columns composed of a circular inner steel tube. Tests on six full‐scale short CECFST columns with the inner circular tube diameter varying from 320 to 500 mm were carried out to study the influences of sectional diameter and the tube thickness of circular CFST columns on their axial performance. A theoretical model is developed using fiber analysis method and validated against a large test database. The accuracy of various codified design models is evaluated and a simple model is proposed to calculate their ultimate strengths. Test results show that CECFST columns have improved load carrying capacity and can sustain large axial loads without significant strength degradation. In addition, increasing the thickness of the steel tube significantly improves the composite action of the steel and concrete of the inner CFST column, which increases the compressive strength of CECFST columns by 27.3%. However, the rate of increase in the compressive strength of the core concrete of the CFST column has been found to be higher for the column with a smaller local slenderness ratio. The ductility of CECFST columns is influenced by the concrete strength and the spacing of the stirrups. Furthermore, the design model suggested in this study can provide a better estimation than the codified design models.

Performance analysis and design of circular high‐strength concrete‐filled double‐skin aluminum tubular short columns under axial loading

“…Concrete‐filled steel tubular (CFST) columns are widely utilized in various modern building structures, especially in high‐rise buildings, owing to their excellent structural performance, which includes large energy‐absorption capacity, high ductility and stiffness 1–4 . As a member of the CFST column family, recently, an innovative composite column referred to as concrete‐filled double‐skin steel tubular (CFDST) columns with concrete infilled between the two centric tubes has captured the interests of researchers 5–9 .…”

“…performance, which includes large energy-absorption capacity, high ductility and stiffness. [1][2][3][4] As a member of the CFST column family, recently, an innovative composite column referred to as concrete-filled double-skin steel tubular (CFDST) columns with concrete infilled between the two centric tubes has captured the interests of researchers. [5][6][7][8][9] The flexural stiffness and fire resistance of CFDST columns are higher compared to CFST columns.…”

Eccentric compression behavior of circular concrete‐filled steel tubes reinforced with internal latticed steel angles

“…Concrete-filled steel tubes (CFSTs) have been widely used in domestic and foreign constructions due to their excellent compression and seismic properties. [1][2][3][4] The "combined actions" between the steel tube and concrete of CFSTs are fully utilized, hence the local stability of steel tube and the ductility of concrete are effectively improved. Therefore, the effect of "'1 + 1 >2" (the capacity of CFSTs is larger than the sum of the individual capacity of steel tube and concrete) can be achieved in CFSTs.…”

“…Therefore, the effect of "'1 + 1 >2" (the capacity of CFSTs is larger than the sum of the individual capacity of steel tube and concrete) can be achieved in CFSTs. [1][2][3][4] In recent years, to improve the compression and shear properties of the core concrete in CFSTs, some scholars have added different types of steel reinforcing elements (such as the reinforcement cages, profiled steels, steel tubes and lattice steel angles, etc.) into CFSTs, thus the steel-reinforced concrete-filled steel tubes (SRCFSTs) are formed.…”

“…Concrete‐filled steel tubes (CFSTs) have been widely used in domestic and foreign constructions due to their excellent compression and seismic properties 1–4 . The “combined actions” between the steel tube and concrete of CFSTs are fully utilized, hence the local stability of steel tube and the ductility of concrete are effectively improved.…”