Steel and Composite Structures

Techno-Press (테크노프레스)
권호 표지
DOI QR코드

DOI QR Code

Behaviour of ultra-high strength concrete encased steel columns subject to ISO-834 fire

  • Du, Yong (College of Civil Engineering, Nanjing Tech University) ;
  • Zhou, Huikai (College of Civil Engineering, Nanjing Tech University) ;
  • Jiang, Jian (School of Mechanics and Civil Engineering, China University of Mining and Technology) ;
  • Liew, J.Y. Richard (College of Civil Engineering, Nanjing Tech University)
  • Received : 2019.07.24
  • Accepted : 2020.10.09
  • Published : 2021.01.25
⟨ Previous Next ⟩

Abstract

Ultra-high strength concrete (UHSC) encased steel columns are receiving growing interest in high-rise buildings owing to their economic and architectural advantages. However, UHSC encased steel columns are not covered by the modern fire safety design code. A total of 14 fire tests are conducted on UHSC (120 MPa) encased steel columns under constant axial loads and exposed to ISO-834 standard fire. The effect of load ratio, slenderness, stirrup spacing, cross-section size and concrete cover to core steel on the fire resistance and failure mode of the specimens are investigated. The applicability of the tabulated method in EC4 (EN 1994-1-2-2005) and regression formula in Chinese code (DBJ/T 15-81-2011) to fire resistance of UHSC encased steel columns are checked. Generally, the test results reveal that the vertical displacement-heating time curves can be divided into two phases, i.e. thermal expansion and shortening to failure. It is found that the fire resistance of column specimens increases with the increase of the cross-section size and concrete cover to core steel, but decreases with the increase of the load ratio and slenderness. The EC4 method overestimates the fire resistance up to 186% (220 min), while the Chinese code underestimates it down to 49%. The Chinese code has a better agreement than EC4 with the test results since the former considers the effect of the load ratio, slenderness, cross section size directly in its empirical formula. To estimate the fire resistance precisely can improve the economy of structural fire design of ultra-high strength concrete encased steel columns.

Keywords

Acknowledgement

The authors would like to acknowledgment the financial support by the National Natural Science Foundation of China [No. 51878348], and National Key R&D Program of China [No. 2018YFC0705704].

References

  1. ASTM E 8M/E8M (2016), Standard test method for tension testing of metallic materials, ASTM International, West Conshohocken, PA, USA.
  2. Choi, E.G., Kim H.S. and Shin Y.S. (2012), "Performance of fire damaged steel reinforced high strength concrete (SRHSC) columns", Steel Compos. Struct., 13(6), 521-537. https://doi.org/10.12989/scs.2012.13.6.521.
  3. DBJ/T 15-81-2011. Code for fire resistance design of concrete structures in buildings. Department of Housing and Urban-Rural Development of Guangdong Province, China.
  4. Du, Y. and Gou, Z.M. (2019), "Application of the Non-Contact Video Gauge on the Mechanical Properties Test for Steel Cable at Elevated Temperature", Appl. Sci., 9(8). 1670. https://doi.org/10.3390/app9081670.
  5. Du, Y., Qi, H.H., Huang, S.S. and Liew, J.Y.R. (2020) "Experimental study on the spalling behaviour of ultra high strength concrete in fire", Constr. Build. Mater., 258, 120334. https://doi.org/10.1016/j.conbuildmat.2020.120334.
  6. Du, Y., Xiong, M.X., Zhu, J. and Liew, J.Y.R. (2019), "Compressive and flexural behaviours of ultra-high strength concrete encased steel members", Steel Compos. Struct., 33(6), 849-864. https://doi.org/10.12989/scs.2019.33.6.849.
  7. Ellobody, E. and Young, B. (2010), "Investigation of concrete encased steel composite columns at elevated temperatures", Thin Wall. Struct., 48, 597-608. https://doi.org/10.1016/j.tws.2010.03.004.
  8. EN 1994-1-1 (2004), Eurocode 4: Design of composite steel and concrete structures-Part 1-1: General rules and rules for buildings, European Committee for Standardization, England.
  9. EN 1994-1-2 (2005), Eurocode 4: Design of composite steel and concrete structures-Part 1-2: General rules — Structural fire design. European Committee for Standardization, England.
  10. Gao, D.Y., You, P.B., Zhang L.J. and Yan, H.H. (2018), "Seismic behavior of SFRC shear wall with CFST columns.", Steel Compos. Struct., 28(5). 527-539. https://doi.org/10.12989/scs.2018.28.5.527.
  11. GB 50010 (2015), Code for design of concrete structures, Ministry of Housing and Urban-Rural Development of the People's Republic of China, China.
  12. GB/T 9978.1-2008 (2008), Fire resistance test-element of building construction - Part 1: general requirements. Chinese Planning published, China.
  13. Han, L.H., Tan, Q.H. and Song, T.Y. (2014), "Fire performance of steel reinforced concrete columns", J. Struct. Eng., 141(4), 04014128. https://doi.org/10.1061/(ASCE)ST.1943-541X.0001081.
  14. Huang Z.F., Tan K.H. Toh W.S. and Phng G.H. (2008), "Fire resistance of composite columns with embedded I-section steel-effects of section size and load level.", J. Struct. Eng., 64, 312-325. https://doi.org/10.1016/j.jcsr.2007.07.002.
  15. Huang, Z.F., Tan, K.H. and Phng, G.H. (2007), "Axial restraint effects on the fire resistance of composite columns encasing I-section steel.", J. Constr. Steel Res., 63(4), 437-447. https://doi.org/10.1016/j.jcsr.2006.07.001.
  16. Joao, P.C.R., Antonio, J.M.C., and Tiago, A.C. (2015), "Behaviour of composite columns made of totally encased steel sections in fire.", J. Struct. Eng., 105, 97-106. https://doi.org/10.1016/j.jcsr.2014.10.030.
  17. Liew, J.Y.R., Xiong M.X. and Xiong, D.X. (2016), "Design of Concrete Filled Tubular Beam-columns with High Strenght Steel and Concrete.", Struct., 8, 213-226. https://doi.org/10.1016/j.istruc.2016.05.005.
  18. Malhotra, H.L. and Stevens, R.F. (1964), "Fire resistance of encased steel stanchions.", Proc. Instn. Civ. Engrs., 27, 77-97. https://doi.org/10.1680/iicep.1964.10371.
  19. Mao, X.Y. and Kodur, V.K.R. (2011), "Fire resistance of concrete encased steel columns under 3- and 4-side standard heating", J. Struct. Eng., 67, 270-280. https://doi.org/10.1016/j.jcsr.2010.11.006.
  20. Wang, P.J., Xia, J.H. and Du, Q.D. (2015), "Temperature rise of a protected steel column exposed to fire from two adjacent sides", Fire Tech., 52(6), 1887-1914. https://doi.org/10.1007/s10694-015-0528-4.
  21. Xiong, M.X., Xiong, D.X. and Liew, J.Y.R. (2017), "Behaviour of steel tubular members infilled with ultra-strength concrete.", J. Constr. Steel Res., 138, 168-183. https://doi.org/10.1016/j.jcsr.2017.07.001.
  22. Xue, J.Y., Chen, Z.P., Zhao, H.T., Gao, L. and Liu, Z.Q. (2012), "Shear mechanism and bearing capacity calculation on steel reinforced concrete special-shaped columns", Steel Compos. Struct., 13(5), 473-487. https://doi.org/10.3901/JME.2008.05.160.
  23. Zhu, W.Q., Jia, J.Q. and Zhang, J.G. (2017), "Experimental research on seismic behavior of steel reinforced high-strength concrete short columns", Steel Compos. Struct., 25(5), 603-615. https://doi.org/10.12989/scs.2017.25.5.603.