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Modeling of heated concrete-filled steel tubes with steel fiber and tire rubber under axial compression

  • Sabetifar, Hassan (Department of Civil Engineering, Faculty of Engineering and Technology, University of Mazandaran) ;
  • Nematzadeh, Mahdi (Department of Civil Engineering, Faculty of Engineering and Technology, University of Mazandaran) ;
  • Gholampour, Aliakbar (College of Science and Engineering, Flinders University)
  • 투고 : 2021.08.25
  • 심사 : 2022.01.03
  • 발행 : 2022.01.25

초록

Concrete-filled steel tubes (CFSTs) are increasingly used as composite sections in structures owing to their excellent load bearing capacity. Therefore, predicting the mechanical behavior of CFST sections under axial compression loading is vital for design purposes. This paper presents the first study on the nonlinear analysis of heated CFSTs with high-strength concrete core containing steel fiber and waste tire rubber under axial compression loading. CFSTs had steel fibers with 0, 1, and 1.5% volume fractions and 0, 5, and 10% rubber particles as sand alternative material. They were subjected to 20, 250, 500, and 750℃ temperatures. Using flow rule and analytical analysis, a model is developed to predict the load bearing capacity of steel tube, and hoop strain-axial strain relationship, and axial stress-volumetric strain relationship of CFSTs. An elastic-plastic analysis method is applied to determine the axial and hoop stresses of the steel tube, considering elastic, yield, and strain hardening stages of steel in its stress-strain curve. The axial stress in the concrete core is determined as the difference between the total experimental axial stress and the axial stress of steel tube obtained from modeling. The results show that steel tube in CFSTs under 750℃ exhibits a higher load bearing contribution compared to those under 20, 250, and 500℃. It is also found that the ratio of load bearing capacity of steel tube at peak point to the load bearing capacity of CFST at peak load is noticeable such that this ratio is in the ranges of 0.21-0.33 and 0.31-0.38 for the CFST specimens with a steel tube thickness of 2 and 3.5 mm, respectively. In addition, after the steel tube yielding, the load bearing capacity of the tube decreases due to the reduction of its axial stiffness and the increase of hoop strain rate, which is in the range of about 20 to 40%.

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참고문헌

  1. Abendeh, R., Ahmad, H.S. and Hunaiti, Y.M. (2016), "Experimental studies on the behavior of concrete-filled steel tubes incorporating crumb rubber", J. Constr. Steel Res., 122, 251-260. https://doi.org/10.1016/j.jcsr.2016.03.022.
  2. Afroughsabet, V., Biolzi, L. and Ozbakkaloglu, T. (2016), "High-performance fiber-reinforced concrete: A review", J. Mater. Sci., 51(14), 6517-6551. https://doi.org/10.1007/s10853-016-9917-4.
  3. Afroughsabet, V., Biolzi, L. and Ozbakkaloglu, T. (2017), "Influence of double hooked-end steel fibers and slag on mechanical and durability properties of high performance recycled aggregate concrete", Compos. Struct., 181, 273-284. https://doi.org/10.1016/j.compstruct.2017.08.086.
  4. Ahmed, M., Liang, Q.Q., Patel, V.I. and Hadi, M.N. (2018), "Nonlinear analysis of rectangular concrete-filled double steel tubular short columns incorporating local buckling", Eng. Struct., 175, 13-26. https://doi.org/10.1016/j.engstruct.2018.08.032.
  5. Alarcon-Ruiz, L., Platret, G., Massieu, E. and Ehrlacher, A. (2005), "The use of thermal analysis in assessing the effect of temperature on a cement paste", Cement Concrete Res., 35(3), 609-613. https://doi.org/10.1016/j.cemconres.2004.06.015.
  6. Alrebeh, S.K. and Ekmekyapar, T. (2019), "Structural performance of short concrete-filled steel tube columns with external and internal stiffening under axial compression", Struct., 20, 702-716. https://doi.org/10.1016/j.istruc.2019.06.015.
  7. Binici, B. (2005), "An analytical model for stress-strain behavior of confined concrete", Eng. Struct., 27(7), 1040-1051. https://doi.org/10.1016/j.engstruct.2005.03.002.
  8. Bisht, K. and Ramana, P.V. (2017), "Evaluation of mechanical and durability properties of crumb rubber concrete", Constr. Build. Mater., 155, 811-817. https://doi.org/10.1016/j.conbuildmat.2017.08.131.
  9. Cai, J., Pan, J. and Wu, Y. (2015), "Mechanical behavior of steel-reinforced concrete-filled steel tubular (SRCFST) columns under uniaxial compressive loading", Thin Wall. Struct., 97, 1-10. https://doi.org/10.1016/j.tws.2015.08.028.
  10. Cetisli, F. and Naito, C.J. (2009), "Concrete subjected to varying confinement, I: Experimental evaluation", J. Adv. Concrete Tech., 7(2), 239-249. https://doi.org/10.3151/jact.7.239.
  11. Chalioris, C.E. and Panagiotopoulos, T.A. (2018), "Flexural analysis of steel fibre-reinforced concrete members", Comput. Concrete, 22(1), 11-25. https://doi.org/10.12989/cac.2018.22.1.011.
  12. Dadmand, B., Pourbaba, M., Sadaghian, H. and Mirmiran, A. (2020), "Experimental and numerical investigation of mechanical properties in steel fiber-reinforced UHPC", Comput. Concrete, 26(5), 451-465. https://doi.org/10.12989/cac.2020.26.5.451.
  13. Dai, X. and Lam, D. (2012), "Shape effect on the behaviour of axially loaded concrete filled steel tubular stub columns at elevated temperature", J. Constr. Steel Res., 73, 117-127. https://doi.org/10.1016/j.jcsr.2012.02.002.
  14. Duarte, A., Silva, B., Silvestre, N., De Brito, J., Julio, E. and Castro, J. (2016), "Tests and design of short steel tubes filled with rubberised concrete", Eng. Struct., 112, 274-286. https://doi.org/10.1016/j.engstruct.2016.01.018.
  15. Elchalakani, M. (2015), "High strength rubberized concrete containing silica fume for the construction of sustainable road side barriers", Struct., 1, 20-38. https://doi.org/10.1016/j.istruc.2014.06.001.
  16. Elistratkin, M.Y., Lesovik, V.S., Zagorodnjuk, L.H., Pospelova, E.A. and Shatalova, S.V. (2018), "New point of view on materials development", IOP Conference Series: Materials Science and Engineering, March.
  17. Ellobody, E., Young, B. and Lam, D. (2006), "Behaviour of normal and high strength concrete-filled compact steel tube circular stub columns", J. Constr. Steel Res., 62(7), 706-715. https://doi.org/10.1016/j.jcsr.2005.11.002.
  18. Farhan, N.A., Sheikh, M.N. and Hadi, M.N. (2020), "effect of steel fiber on engineering properties of geopolymer concrete", ACI Mater. J., 117(3), 29-40. https://doi.org/10.14359/51724591.
  19. Fediuk, R.S. (2016), "Mechanical activation of construction binder materials by various mills", IOP Conference Series: Materials Science and Engineering, April.
  20. Ferretti, E. (2004), "On poisson's ratio and volumetric strain in concrete" Int. J. Fract., 126(3), 49-55. https://doi.org/10.1023/B:FRAC.0000026587.43467.e6.
  21. Gencel, O., Brostow, W., Datashvili, T. and Thedford, M. (2011), "Workability and mechanical performance of steel fiber-reinforced self-compacting concrete with fly ash", Compos. Interface., 18(2), 169-184. https://doi.org/10.1163/092764411X567567.
  22. Gholampour, A., Fallah Pour, A., Hassanli, R. and Ozbakkaloglu, T. (2019), "Behavior of actively confined rubberized concrete under cyclic axial compression", J. Struct. Eng., 145(11), 04019131. https://doi.org/10.1061/(asce)st.1943-541x.0002434
  23. Gholampour, A. and Ozbakkaloglu, T. (2018a), "Behavior of steel fiber-reinforced concrete-filled FRP tube columns: Experimental results and a finite element model", Compos. Struct., 194, 252-262. https://doi.org/10.1016/j.compstruct.2018.03.094.
  24. Gholampour, A. and Ozbakkaloglu, T. (2018b), "Fiber-reinforced concrete containing ultra high-strength micro steel fibers under active confinement", Constr. Build. Mater., 187, 299-306. https://doi.org/10.1016/j.conbuildmat.2018.07.042.
  25. Gholampour, A., Ozbakkaloglu, T. and Hassanli, R. (2017), "Behavior of rubberized concrete under active confinement", Constr. Build. Mater., 138, 372-382. https://doi.org/10.1016/j.conbuildmat.2017.01.105.
  26. Giakoumelis, G. and Lam, D. (2004), "Axial capacity of circular concrete-filled tube columns", J. Constr. Steel Res., 60(7), 1049-1068. https://doi.org/10.1016/j.jcsr.2003.10.001.
  27. Hajjar, J.F. and Gourley, B.C. (1996), "Representation of concrete-filled steel tube cross-section strength", J. Struct. Eng., 122(11), 1327-1336. https://doi.org/10.1061/(ASCE)0733-9445(1996)122:11(1327)
  28. Han, L.H. and Huo, J.S. (2003), "Concrete-filled hollow structural steel columns after exposure to ISO-834 fire standard", J. Struct. Eng., 129(1), 68-78. https://doi.org/10.1061/(asce)0733-9445(2003)129:1(68)
  29. Han, L.H., Yang, Y.F. and Tao, Z. (2003), "Concrete-filled thin-walled steel SHS and RHS beam-columns subjected to cyclic loading", Thin Wall. Struct., 41(9), 801-833. https://doi.org/10.1016/S0263-8231(03)00030-2.
  30. Han, L.H., Yao, G.H. and Tao, Z. (2007), "Performance of concrete-filled thin-walled steel tubes under pure torsion", Thin Wall. Struct., 45(1), 24-36. https://doi.org/10.1016/j.tws.2007.01.008.
  31. Han, L.H., Zhao, X.L., Yang, Y.F. and Feng, J.B. (2003), "Experimental study and calculation of fire resistance of concrete-filled hollow steel columns", J. Struct. Eng., 129(3), 346-356. https://doi.org/10.1061/(asce)0733-9445(2003)129:3(346)
  32. Hoang, A.L. and Fehlinga, E. (2017), "Numerical analysis of circular steel tube confined UHPC stub columns", Comput. Concrete, 19(3), 263-273. https://doi.org/10.12989/cac.2017.19.3.263.
  33. Hosford, W.F. (2010), Solid Mechanics, Cambridge University Press.
  34. Hu, H.T., Huang, C.S., Wu, M.H. and Wu, Y.M. (2003), "Nonlinear analysis of axially loaded concrete-filled tube columns with confinement effect", J. Struct. Eng., 129(10), 1322-1329. https://doi.org/10.1061/(asce)0733-9445(2003)129:10(1322)
  35. Hua, Y.X., Han, L.H., Wang, Q.L. and Hou, C. (2019), "Behaviour of square CFST beam-columns under combined sustained load and corrosion: Experiments", Thin Wall. Struct., 136, 353-366. https://doi.org/10.1016/j.tws.2018.12.037.
  36. Huang, Y., Xiao, J. and Zhang, C. (2012), "Theoretical study on mechanical behavior of steel confined recycled aggregate concrete", J. Constr. Steel Res., 76, 100-111. https://doi.org/10.1016/j.jcsr.2012.03.020.
  37. Ibanez, C., Bisby, L., Rush, D., Romero, M.L. and Hospitaler, A. (2019), "Post-heating response of concrete-filled steel tubular columns under sustained loads", Struct., 21, 90-102. https://doi.org/10.1016/j.istruc.2019.04.003.
  38. Ilki, A. and Demir, U. (2019), "Factors affecting seismic behavior of reinforced concrete structures after fire exposure", NED Univ. J. Res., 1, 31-41. https://doi.org/10.35453/NEDJR-STMECH-2019-0003
  39. Imran, I. and Pantazopoulou, S.J. (1996), "Experimental study of plain concrete under triaxial stress", ACI Mater. J. Am. Concrete Inst., 93(6), 589-601.
  40. Iqbal, S., Ali, A., Holschemacher, K. and Bier, T.A. (2015), "Mechanical properties of steel fiber reinforced high strength lightweight self-compacting concrete", Constr. Build. Mater., 98, 325-333. https://doi.org/10.1016/j.conbuildmat.2015.08.112.
  41. ISO, I. (1999), 834, Fire Resistance Tests-Elements of Building Construction, International Organization for Standardization, Geneva, Switzerland.
  42. Jafarzadeh, H. and Nematzadeh, M. (2020), "Evaluation of post-heating flexural behavior of steel fiber-reinforced high-strength concrete beams reinforced with FRP bars: Experimental and analytical results", Eng. Struct., 225, 111292. https://doi.org/10.1016/j.engstruct.2020.111292.
  43. Jiang, Y., Silva, A., Macedo, L., Castro, J.M., Monteiro, R. and Chan, T.M. (2019), "Concentrated-plasticity modelling of circular concrete-filled steel tubular members under flexure", Struct., 21, 156-166. https://doi.org/10.1016/j.istruc.2019.01.023.
  44. Karimi, A. and Nematzadeh, M. (2020), "Axial compressive performance of steel tube columns filled with steel fiber-reinforced high strength concrete containing tire aggregate after exposure to high temperatures", Eng. Struct., 219, 110608. https://doi.org/10.1016/j.engstruct.2020.110608.
  45. Karimi, A., Nematzadeh, M. and Mohammad-Ebrahimzadeh-Sepasgozar, S. (2020), "Analytical post-heating behavior of concrete-filled steel tubular columns containing tire rubber", Comput. Concrete, 26(6), 467-482. https://doi.org/10.12989/cac.2020.26.6.467.
  46. Kazmi, S.M.S., Munir, M.J. and Wu, Y.F. (2021), "Application of waste tire rubber and recycled aggregates in concrete products: A new compression casting approach", Res. Conse. Recycl., 167, 105353. https://doi.org/10.1016/j.resconrec.2020.105353.
  47. Kodur, V. (1998), "Performance of high strength concrete-filled steel columns exposed to fire", Canadian J. Civil Eng., 25(6), 975-981. https://doi.org/10.1139/l98-023.
  48. Kodur, V. and Lie, T. (1996), "Fire resistance of circular steel columns filled with fiber-reinforced concrete", J. Struct. Eng., 122(7), 776-782. https://doi.org/10.1061/(asce)0733-9445(1996)122:7(776)
  49. Kodur, V. and MacKinnon, D.H. (2000), "Design of concrete-filled hollow structural steel columns for fire endurance", Eng. J. Am. Inst. Steel Constr., 37(1), 13-24.
  50. Koksal, F., Ilki, A., Bayramov, F. and Tasdemir, M. (2006), "Mechanical behavior and optimum design of SFRC plates", Meas. Monit. Model. Concrete Properties, 199-205. https://doi.org/10.1007/978-1-4020-5104-3_24.
  51. Koksal, F., Sahin, Y., Gencel, O. and Yigit, I. (2013), "Fracture energy-based optimisation of steel fibre reinforced concretes", Eng. Fract. Mech., 107, 29-37. https://doi.org/10.1016/j.engfracmech.2013.04.018.
  52. Lie, T. and Kodur, V. (1996), "Thermal and mechanical properties of steel-fibre-reinforced concrete at elevated temperatures", Canadian J. Civil Eng., 23(2), 511-517. https://doi.org/10.1139/l96-055.
  53. Liew, J.R., Xiong, M. and Xiong, D. (2016), "Design of concrete filled tubular beam-columns with high strength steel and concrete", Struct., 8, 213-226. https://doi.org/10.1016/j.istruc.2016.05.005.
  54. Lim, J.C. and Ozbakkaloglu, T. (2015), "Hoop strains in FRP-confined concrete columns: Experimental observations", Mater. Struct., 48(9), 2839-2854. https://doi.org/10.1617/s11527-014-0358-8.
  55. Liu, D., Li, H. and Ren, H. (2020), "Study on the performance of concrete-filled steel tube beam-column joints of new types", Comput. Concrete, 26(6), 547-563. https://doi.org/10.12989/cac.2020.26.6.547.
  56. Liu, R., Li, H., Jiang, Q. and Meng, X. (2020), "Experimental investigation on flexural properties of directional steel fiber reinforced rubberized concrete", Struct., 27, 1660-1669. https://doi.org/10.1016/j.istruc.2020.08.007.
  57. Lu, Y., Li, N., Li, S. and Liang, H. (2015), "Behavior of steel fiber reinforced concrete-filled steel tube columns under axial compression", Constr. Build. Mater., 95, 74-85. https://doi.org/10.1016/j.conbuildmat.2015.07.114.
  58. Memarzadeh, A. and Nematzadeh, M. (2021), "Axial compressive performance of steel reinforced fibrous concrete composite stub columns: Experimental and theoretical study", Struct., 34, 2455-2475. https://doi.org/10.1016/j.istruc.2021.08.130.
  59. Naghipour, M., Ahmadi, M. and Nematzadeh, M. (2022), "Effect of concrete confinement level on load-bearing capacity of steel-reinforced concrete (SRC) columns under eccentric loading: Experiment and FEA model", Struct., 35, 202-213. https://doi.org/10.1016/j.istruc.2021.10.094.
  60. Najigivi, A., Nazerigivi, A. and Nejati, H.R. (2017), "Contribution of steel fiber as reinforcement to the properties of cement-based concrete: A review", Comput. Concrete, 20(2), 155-164. https://doi.org/10.12989/cac.2017.20.2.155.
  61. Nematzadeh, M. and Baradaran-Nasiria, A. (2019), "Mechanical performance of fiber-reinforced recycled refractory brick concrete exposed to elevated temperatures", Comput. Concrete, 24(1), 19-35. https://doi.org/10.12989/cac.2019.24.1.019.
  62. Nematzadeh, M. and Fazli, S. (2020), "Effect of axial loading conditions and confinement type on concrete-steel composite behavior", Comput. Concrete, 25(2), 95-109. https://doi.org/10.12989/cac.2020.25.2.095.
  63. Nematzadeh, M. and Haghinejad, A. (2017), "Analysis of actively-confined concrete columns using prestressed steel tubes", Comput. Concrete, 19(5), 477-488. https://doi.org/10.12989/cac.2017.19.5.477.
  64. Nematzadeh, M., Hasan-Nattaj, F., Gholampour, A., Sabetifar, H. and Ngo, T.D. (2021), "Strengthening of heat-damaged steel fiber-reinforced concrete using CFRP composites: Experimental study and analytical modeling", Struct., 32, 1856-1870. https://doi.org/https://doi.org/10.1016/j.istruc.2021.03.084.
  65. Nematzadeh, M., Karimi, A. and Fallah-Valukolaee, S. (2020a), "Compressive performance of steel fiber-reinforced rubberized concrete core detached from heated CFST", Constr. Build. Mater., 239, 117832. https://doi.org/10.1016/j.conbuildmat.2019.117832.
  66. Nematzadeh, M., Karimi, A. and Gholampour, A. (2020b), "Pre-and post-heating behavior of concrete-filled steel tube stub columns containing steel fiber and tire rubber", Struct., 27, 2346-2364. https://doi.org/10.1016/j.istruc.2020.07.034.
  67. Nematzadeh, M. and Mousavi, R. (2021), "Post-fire flexural behavior of functionally graded fiber-reinforced concrete containing rubber", Comput. Concrete, 27(5), 417-435. https://doi.org/10.12989/cac.2021.27.5.417.
  68. Nematzadeh, M., Nazari, A. and Tayebi, M. (2022), "Post-fire impact behavior and durability of steel fiber-reinforced concrete containing blended cement-zeolite and recycled nylon granules as partial aggregate replacement", Archiv. Civil Mech. Eng., 22(1), 1-25. https://doi.org/10.1007/s43452-021-00324-1.
  69. Ozbakkaloglu, T., Gholampour, A. and Lim, J.C. (2016), "Damage-plasticity model for FRP-confined normal-strength and high-strength concrete", J. Compos. Constr., 20(6), 04016053. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000712
  70. Patel, V.I., Liang, Q.Q. and Hadi, M.N. (2014), "Numerical analysis of high-strength concrete-filled steel tubular slender beam-columns under cyclic loading", J. Constr. Steel Res., 92, 183-194. https://doi.org/10.1016/j.jcsr.2013.09.008.
  71. Perumal, R. (2014), "Performance and modeling of high-performance steel fiber reinforced concrete under impact loads", Comput. Concrete, 13(2), 255-270. https://doi.org/10.12989/cac.2014.13.2.255.
  72. Portoles, J., Serra, E. and Romero, M.L. (2013), "Influence of ultra-high strength infill in slender concrete-filled steel tubular columns", J. Constr. Steel Res., 86, 107-114. https://doi.org/10.1016/j.jcsr.2013.03.016.
  73. Ramadoss, P. and Nagamani, K. (2013), "Stress-strain behavior and toughness of high-performance steel fiber reinforced concrete in compression", Comput. Concrete, 11(2), 149-167. https://doi.org/10.12989/cac.2013.11.2.149.
  74. Raouffard, M.M. and Nishiyama, M. (2016), "Residual load bearing capacity of reinforced concrete frames after fire", J. Adv. Concrete Tech., 14(10), 625-633. https://doi.org/10.3151/jact.14.625.
  75. Sabetifar, H. and Nematzadeh, M. (2021), "An evolutionary approach for formulation of ultimate shear strength of steel fiber-reinforced concrete beams using gene expression programming", Struct., 34, 4965-4976. https://doi.org/10.1016/j.istruc.2021.10.075.
  76. Semenov, P.A., Uzunian, A.V., Davidenko, A.M., Derevschikov, A.A., Goncharenko, Y.M., Kachanov, V.A. and Tamulaitis, G. (2007), "First study of radiation hardness of lead tungstate crystals at low temperatures", Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 582(2), 575-580. https://doi.org/10.1016/j.nima.2007.08.178.
  77. Shui, Z., Xuan, D., Chen, W., Yu, R. and Zhang, R. (2009), "Cementitious characteristics of hydrated cement paste subjected to various dehydration temperatures", Constr. Build. Mater., 23(1), 531-537. https://doi.org/10.1016/j.conbuildmat.2007.10.016.
  78. Silva, A., Jiang, Y., Castro, J.M. and Monteiro, R. (2017), "Experimental characterisation of the flexural behaviour of rubberized concrete-filled steel tubular members", 1(2-3), 2147-2156.
  79. Silva, A., Jiang, Y., Castro, J.M., Silvestre, N. and Monteiro, R. (2016a), "Experimental assessment of the flexural behaviour of circular rubberized concrete-filled steel tubes", J. Constr. Steel Res., 122, 557-570. https://doi.org/10.1016/j.jcsr.2016.04.016.
  80. Silva, A., Jiang, Y., Castro, J.M., Silvestre, N. and Monteiro, R. (2017), "Monotonic and cyclic flexural behaviour of square/rectangular rubberized concrete-filled steel tubes", J. Constr. Steel Res., 139, 385-396. https://doi.org/10.1016/j.jcsr.2017.09.006.
  81. Silva, A., Jiang, Y., Macedo, L., Castro, J.M., Monteiro, R. and Silvestre, N. (2016b), "Seismic performance of composite moment-resisting frames achieved with sustainable CFST members", Front. Struct. Civil Eng., 10(3), 312-332. https://doi.org/10.1007/s11709-016-0345-y.
  82. Song, P. and Hwang, S. (2004), "Mechanical properties of high-strength steel fiber-reinforced concrete", Constr. Build. Mater., 18(9), 669-673. https://doi.org/10.1016/j.conbuildmat.2004.04.027.
  83. Susantha, K., Ge, H. and Usami, T. (2001), "Uniaxial stress-strain relationship of concrete confined by various shaped steel tubes", Eng. Struct., 23(10), 1331-1347. https://doi.org/10.1016/S0141-0296(01)00020-7.
  84. Tang, J., Hino, S.I., Kuroda, I. and Ohta, T. (1996), "Modeling of stress-strain relationships for steel and concrete in concrete filled circular steel tubular columns", Kou Kouzou Rombunshuu, 3(11), 35-46. https://doi.org/10.11273/jssc1994.3.11_35.
  85. Tayebi, M. and Nematzadeh, M. (2021), "Effect of hot-compacted waste nylon fine aggregate on compressive stress-strain behavior of steel fiber-reinforced concrete after exposure to fire: Experiments and optimization", Constr. Build. Mater., 284, 122742. https://doi.org/10.1016/j.conbuildmat.2021.122742.
  86. Tokgoz, S. and Dundar, C. (2010), "Experimental study on steel tubular columns in-filled with plain and steel fiber reinforced concrete", Thin Wall. Struct., 48(6), 414-422. https://doi.org/10.1016/j.tws.2010.01.009.
  87. Youssf, O., ElGawady, M.A. and Mills, J.E. (2015), "Experimental investigation of crumb rubber concrete columns under seismic loading", Struct., 3, 13-27. https://doi.org/10.1016/j.istruc.2015.02.005.
  88. Zhang, W. and Shahrooz, B.M. (1999), "Strength of short and long concrete-filled tubular columns", Struct. J., 96(2), 230-238.