OJCE  Vol.8 No.1 , March 2018
Effect of Severe Temperatures and Restraint on Instability and Buckling of Elliptical Steel Columns
Abstract: This paper presents the findings of an experimental research to investigate the performance of axially restrained elliptical hollow (EHS) steel columns subjected to severe hydrocarbon fire. The test programme involved 12 steel columns presenting 2 oval sections 200 × 100 × 8 mm and 300 × 150 × 8 mm and yielding 2 slenderness λ = 51 and 33. The 1800 mm columns were tested under loading ratios ranging between 0.2 and 0.6 of the ultimate strength determined using EC3 and under axial restraint degree ranging from 0 to 0.16.  The obtained results of axial displacements, lateral displacements, measured restraint forces, and high temperatures are presented in the paper. It was found that introducing restraint to the columns with elliptical section produces high restraint forces which reduce the time to lose lateral stability. This is more evident in cases of lower load ratios than the higher load ratios. The numerical study presented in this paper involved building a finite element model to simulate the columns behaviour in fire. The model was validated using the test results obtained from unrestrained and restrained columns fire tests. The model demonstrated good agreement in the prediction of failure times and failure mechanisms of local and overall buckling. The FEM model was then used to conduct a parametric analysis involving factors of slenderness, restraint and loading. The conclusions drawn for this research are presented at the end of the paper.
Cite this paper: Ali, F. and Nadjai, A. (2018) Effect of Severe Temperatures and Restraint on Instability and Buckling of Elliptical Steel Columns. Open Journal of Civil Engineering, 8, 41-57. doi: 10.4236/ojce.2018.81004.

[1]   Gardner, L. and Chan, T.M. (2007) Cross-Section Classification of Elliptical Hollow Sections. Steel and Composite Structures, 7, 185-200.

[2]   Gardner, L. and Chan, T.M. (2009) Structural Design Rules for Elliptical Hollow Sections. 12th International Symposium on Tubular Structures, 323-329.

[3]   Gardner, L. and Ministro, A. (2005) Structural Steel Oval Hollow Sections. Structural Engineer, 83, 32-36.

[4]   Chan, T.M. and Gardner, L. (2008) Compressive Resistance of Hot-Rolled Elliptical Hollow Sections. Engineering Structure, 30, 522-532.

[5]   Zhu, J.-H. and Young, B. (2012) Design of Cold-Formed Steel Oval Hollow Section Columns. Journal of Constructional Steel Research, 71, 26-37.

[6]   Scullion, T., Ali, F. and Nadjai, A. (2011) Effect of Axial Restraint on the Performance of Elliptical Hollow Section Steel Columns, in Hydrocarbon Fire. Engineering Structures, 33, 3155-3161.

[7]   Scullion, T., Ali, F. and Nadjai, A. (2011) Experimental Study on Performance of Elliptical Section Steel Columns under Hydrocarbon Fire. Journal of Constructional Steel, 67, 986-991.

[8]   Faris, A., Nadjai, A. and Goodfellow, N. (2016) Experimental and Numerical Study on the Performance of Hollow and Concrete-Filled Elliptical Steel Columns Subjected to Severe Fire. Fire and Materials, 40, 635-652.

[9]   Espinos, A., Romero, M.L. and Hospitaler, A. (2013) Fire Design Method for Bar-Reinforced Circular and Elliptical Concrete Filled Tubular Columns. Engineering Structures, 56, 384-395.

[10]   Espinos, A., Gardner, L., Romero, M.L. and Hospitaler, A. (2011) Fire Behaviour of Concrete Filled Elliptical Steel Columns. Thin-Walled Structures, 49, 239-255.

[11]   Eurocode 1 (2002) BS EN 1991-1-2. Eurocode 1. Actions on Structures. General Actions. Actions on Structures Exposed to Fire, 2002.

[12]   Eurocode 3 (2005) BS EN 1993-1-1. Eurocode 3. Design of Steel Structures. General Rules and Rules for Buildings.

[13]   Eurocode 3 (2005) National Annex to Eurocode 3. Design of Steel Structures. General Rules and Rules for Buildings.

[14]   TNO Building and Construction Research (2011) DIANA Finite Element Analysis User Manuals, Release 9.4.3, Delft.