Abstract
Spiral-welded tubes (SWTs) are fabricated by helically bending a steel plate-coil and welding the resulting abutting edges. The cost-effectiveness of concrete-filled stainless-steel tube (CFSST) columns can be improved by using SWTs rather than longitudinally welded tubes as their fabrication is more economical and efficient. However, due to the high level of residual stresses and unique imperfection patterns present in SWTs, such concrete-filled spiral-welded stainless-steel tube (CF-SWSST) columns require separate consideration. Even though most practical columns are ‘long columns’, where the capacity is length dependant, only the behaviour of CF-SWSST short columns has previously been investigated. To address this research gap, twelve CF-SWSST long columns with effective length to diameter (Le/D) ratios in the range 10.5–12.0 were tested under axial compression considering end load eccentricity ratios of 0, 0.15D and 0.4D and diameter to thickness ratios (D/t) ranging from 62 to 116. A global flexural buckling type failure mode was obtained for all the tested columns similar to that reported for CFSST long columns of other tube types. It was found that the guidelines of several existing design standards relating to mild-steel concrete-filled steel tube (CFST) columns are directly applicable to CF-SWSST long columns under eccentric loading. However, for concentric loading the predictions were non-conservative indicating that separate guidelines are needed for purely axially loaded CF-SWSSTs, including procedures to consider column slenderness effects of CFSSTs distinct from those specified for mild-steel CFSTs. In addition, fibre-element analyses considering unconfined concrete models gave conservative, yet close, predictions of the experimental eccentric axial capacities which was consistent with the experimentally determined negligible level of concrete confinement.
| Original language | English |
|---|---|
| Pages (from-to) | 201-226 |
| Number of pages | 26 |
| Journal | Journal of Constructional Steel Research |
| Volume | 161 |
| DOIs | |
| Publication status | Published - 1 Oct 2019 |
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Concrete-filled spiral-welded stainless-steel tube long columns under concentric and eccentric axial compression loading. / Gunawardena, Yasoja; Aslani, Farhad.
In: Journal of Constructional Steel Research, Vol. 161, 01.10.2019, p. 201-226.Research output: Contribution to journal › Article
TY - JOUR
T1 - Concrete-filled spiral-welded stainless-steel tube long columns under concentric and eccentric axial compression loading
AU - Gunawardena, Yasoja
AU - Aslani, Farhad
PY - 2019/10/1
Y1 - 2019/10/1
N2 - Spiral-welded tubes (SWTs) are fabricated by helically bending a steel plate-coil and welding the resulting abutting edges. The cost-effectiveness of concrete-filled stainless-steel tube (CFSST) columns can be improved by using SWTs rather than longitudinally welded tubes as their fabrication is more economical and efficient. However, due to the high level of residual stresses and unique imperfection patterns present in SWTs, such concrete-filled spiral-welded stainless-steel tube (CF-SWSST) columns require separate consideration. Even though most practical columns are ‘long columns’, where the capacity is length dependant, only the behaviour of CF-SWSST short columns has previously been investigated. To address this research gap, twelve CF-SWSST long columns with effective length to diameter (Le/D) ratios in the range 10.5–12.0 were tested under axial compression considering end load eccentricity ratios of 0, 0.15D and 0.4D and diameter to thickness ratios (D/t) ranging from 62 to 116. A global flexural buckling type failure mode was obtained for all the tested columns similar to that reported for CFSST long columns of other tube types. It was found that the guidelines of several existing design standards relating to mild-steel concrete-filled steel tube (CFST) columns are directly applicable to CF-SWSST long columns under eccentric loading. However, for concentric loading the predictions were non-conservative indicating that separate guidelines are needed for purely axially loaded CF-SWSSTs, including procedures to consider column slenderness effects of CFSSTs distinct from those specified for mild-steel CFSTs. In addition, fibre-element analyses considering unconfined concrete models gave conservative, yet close, predictions of the experimental eccentric axial capacities which was consistent with the experimentally determined negligible level of concrete confinement.
AB - Spiral-welded tubes (SWTs) are fabricated by helically bending a steel plate-coil and welding the resulting abutting edges. The cost-effectiveness of concrete-filled stainless-steel tube (CFSST) columns can be improved by using SWTs rather than longitudinally welded tubes as their fabrication is more economical and efficient. However, due to the high level of residual stresses and unique imperfection patterns present in SWTs, such concrete-filled spiral-welded stainless-steel tube (CF-SWSST) columns require separate consideration. Even though most practical columns are ‘long columns’, where the capacity is length dependant, only the behaviour of CF-SWSST short columns has previously been investigated. To address this research gap, twelve CF-SWSST long columns with effective length to diameter (Le/D) ratios in the range 10.5–12.0 were tested under axial compression considering end load eccentricity ratios of 0, 0.15D and 0.4D and diameter to thickness ratios (D/t) ranging from 62 to 116. A global flexural buckling type failure mode was obtained for all the tested columns similar to that reported for CFSST long columns of other tube types. It was found that the guidelines of several existing design standards relating to mild-steel concrete-filled steel tube (CFST) columns are directly applicable to CF-SWSST long columns under eccentric loading. However, for concentric loading the predictions were non-conservative indicating that separate guidelines are needed for purely axially loaded CF-SWSSTs, including procedures to consider column slenderness effects of CFSSTs distinct from those specified for mild-steel CFSTs. In addition, fibre-element analyses considering unconfined concrete models gave conservative, yet close, predictions of the experimental eccentric axial capacities which was consistent with the experimentally determined negligible level of concrete confinement.
KW - CFST
KW - Concrete-filled steel tube
KW - Eccentric axial loading
KW - Long columns
KW - Self-compacting concrete
KW - Spiral-welded tubes
KW - Stainless-steel
KW - SWT
UR - http://www.scopus.com/inward/record.url?scp=85068567536&partnerID=8YFLogxK
U2 - 10.1016/j.jcsr.2019.07.006
DO - 10.1016/j.jcsr.2019.07.006
M3 - Article
VL - 161
SP - 201
EP - 226
JO - Journal of Constructional Steel Research
JF - Journal of Constructional Steel Research
SN - 0143-974X
ER -