Safety evaluation of circular concrete-filled steel columns designed according to Brazilian building code NBR 8800:2008

Oliveira, W.L.A. de; Beck, A.T.; Debs, A.L.H.C. El

doi:10.1590/S1983-41952008000300001

Abstracts

This paper presents an investigation of the safety of circular concrete-filled steel columns designed according to Brazilian building code NBR 8800:2008. The investigation is based on a comparison of code provisions to column strength obtained in 32 experimental tests, and on a comparison to provisions of the equivalent American and European codes. The modeling error of theoretical code resistance models is evaluated. An analysis of covariance is performed in order to identify tendencies of these models. The study reveals that the resistance model used in the Brazilian code is compatible with foreign codes, in terms of bias and variances. The study reveals an additional safety margin of the order of 10% for the NBR8800 code, when partial safety factors are removed. Reliability analysis is performed for 3888 column configurations, resulting in reliability indexes that cover the building codes application spectrum. The study shows that the Brazilian code presents reliability indexes which are compatible with foreign codes.

Concrete-filled columns; experimental analysis; safety; reliability

Este artigo apresenta uma investigação da segurança de pilares mistos preenchidos de seção circular, dimensionados segundo a norma brasileira NBR 8800:2008. Esta investigação é feita com base na comparação de previsões normativas com a resistência obtida em 32 ensaios experimentais, bem como na comparação com as normas americana e européia correspondentes. O erro de modelo das equações teóricas de resistência destas normas é determinado. Uma análise de covariância é realizada para verificar tendências das equações de resistência. O estudo mostra que o modelo de resistência utilizado na norma brasileira é compatível com as normas estrangeiras, em termos de tendenciosidade e variância. O estudo revela uma margem de segurança adicional da ordem de 10% na NBR8800, quando removidos os coeficientes parciais de segurança. Uma análise de confiabilidade é realizada para 3888 configurações de pilar, resultando em índices de confiabilidade que refletem a segurança do universo de pilares cobertos pelas normas. O estudo mostra que a norma brasileira apresenta índices de confiabilidade compatíveis com as normas estrangeiras.

NBR 8800; pilares mistos preenchidos; análise experimental; segurança; confiabilidade

Safety evaluation of circular concrete-filled steel columns designed according to Brazilian building code NBR 8800:2008

W.l.a. De oliveira^I ; A.t. Beck ^I ^I ; A.l.h.c. El Debs ^I ^I ^I

^IDoutor, Departamento de Engenharia de Estruturas, Escola de Engenharia de São Carlos, USP, wluiz@sc.usp.br, Av. Trabalhador São-Carlense nº 400, 13566-590, São Carlos, Brasil

^I^IProfessor Doutor, Departamento de Engenharia de Estruturas, Escola de Engenharia de São Carlos, USP, atbeck@sc.usp.br, Av. Trabalhador São-Carlense nº 400, 13566-590, São Carlos, Brasil

^I^I^IProfessora Doutora, Departamento de Engenharia de Estruturas, Escola de Engenharia de São Carlos, USP, analucia@sc.usp.br, Av. Trabalhador São-Carlense nº 400, 13566-590, São Carlos, Brasil

ABSTRACT

This paper presents an investigation of the safety of circular concrete-filled steel columns designed according to Brazilian building code NBR 8800:2008. The investigation is based on a comparison of code provisions to column strength obtained in 32 experimental tests, and on a comparison to provisions of the equivalent American and European codes. The modeling error of theoretical code resistance models is evaluated. An analysis of covariance is performed in order to identify tendencies of these models. The study reveals that the resistance model used in the Brazilian code is compatible with foreign codes, in terms of bias and variances. The study reveals an additional safety margin of the order of 10% for the NBR8800 code, when partial safety factors are removed. Reliability analysis is performed for 3888 column configurations, resulting in reliability indexes that cover the building codes application spectrum. The study shows that the Brazilian code presents reliability indexes which are compatible with foreign codes.

Keywords: Concrete-filled columns, experimental analysis, safety, reliability.

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REFERENCES

[01] Associação Brasileira de Normas Técnicas. NBR 8800:2008. Projeto e execução de estruturas de aço e de estruturas mistas aço-concreto de edifícios: Procedimento. Rio de Janeiro, 2008.
[02] Fakury, R.H. (2007). Sobre a revisão da norma brasileira de projeto de estruturas de aço e estruturas mistas de aço e concreto, a NBR 8800. Revista Escola de Minas - REM, Ouro Preto, v. 60, n. 02, p. 233-239. Abr. - Jun. 2007.
[03] American Institute of Steel Construction. ANSI/AISC 360: Specification for Structural Steel Buildings. Chicago, Illinois. 2005.
[04] EN 1994-1-1:2004. Design of composite steel and concrete structures, Part 1-1:General rules and rules for buildings. EUROCODE 4, European Committee for Standardization, 2004.
[05] Johansson, M.; Gylltoft, K.(2001). Structural behavior of slender circular steel-concrete composite columns under various means of load application. Steel and Composite Structures, v.1, n.4, p.393-410.
[06] De Nardin, S.; El Debs, A.L.H.C. (2007). Axial load behaviour of concrete-filled steel tubular columns. Structures and Buildings, v. 160, p. 13-22.
[07] De Nardin, S.; El Debs, A.L.H.C. (2004). Na experimental study of connections between I-beams and concrete filled steel tubular columns. Steel and Composite Structures, v.04, n.04, p. 303-315.
[08] Roeder, C.W.; Cameron, B.; Brown, C.B. (1999). Composite action in concrete filled tubes. Journal of Structural Engineering, ASCE, v.125, n.5, p.477-484. May.
[09] Elremaily, A.; Azizinamini, A. (2002). Behavior and strength of circular concrete-filled tube columns. Journal of Constructional Steel Research. v.58, n.12, p.1567-1591. Dec.
[10] Giakoumelis, G.; Lam, D. (2004). Axial capacity of circular concrete-filled tube columns. Journal of Constructional Steel Research. v.60, n.7, p.1049-1068. July.
[11] Zeghiche, J.; Chaoui, K. (2005). An experimental behaviour of concrete-filled steel tubular columns. Journal of Constructional Steel Research. v.61, n.1, p.53-66. Jan.
[12] Gupta, P.K.; Sarda, S.M.; Kumar, M.S. (2007). Experimental and computacional study of concrete filled steel tubular columns under axial loads. Journal of Constructional Steel Research. v.63, n.2, p.182-193.
[13] Yu, Z.; Ding, F.; Cai, C.S. (2007). Experimental behavior of circular concrete-filled steel tube stub columns. Journal of Constructional Steel Research.v.63, n.2, p.165-174. Feb.
[14] O'Shea, M.D.; Bridge, R.Q. (2000). Design of circular thin-walled concrete filled steel tubes. Journal of Structural Engineering, ASCE, v.126, n.11, p.1295-1303.
[15] American Society for Testing and Materials. (1992). ASTM A370: Standard test methods for tension testing of metallic materials. Philadelphia.
[16] Oliveira, W.L.A. (2008). Análise teórico experimental de pilares mistos preenchidos de seção circular. Tese (Doutorado) - Escola de Engenharia de São Carlos, Universidade de São Paulo, São Carlos.
[17] Faber, M.H.(2006). Risk and Safety in Civil, Surveying and Environmental Engineering, Swiss Federal Institute of Technology, ETHZ, Switzerland.
[18] Ellingwood, B. and Galambos, T.V. (1982). Probability-based criteria for structural design, Structural Safety 1, pp. 15-26.
[19] Melchers, R.E. (1999). Structural Reliability Analysis and Prediction, 2nd edition, John Wiley and Sons, NY.
[20] Beck, A.T. and Rosa, E. (2006). Structural Reliability Analysis Using Deterministic Finite Element Programs", Latin American Journal of Solids and Structures. v.3, p.197-222.
[21] Beck, A. T.(2007) Computer-aided teaching of structural reliability. XXVIII Iberian Latin-American Congress on Computational Methods in Engineering, Porto - Portugal.
[22] prEN 1990: Basis of Structural Design - Annex C: Basis for Partial Factor Design and Reliability Analysis". European Committee for Standardization, Brussels, "Final Draft", 2001.
[23] Beck, A.T. and Doria, A.S. (2008). Reliability Analysis of I-section Steel Columns Designed According to New Brazilian Building Codes, J. of the Braz. Soc. of Mech. Sci. and Eng., Vol. 30, No. 2. p. 152-159.

Publication Dates

Publication in this collection
19 Sept 2014
Date of issue
Sept 2008

This work is licensed under a Creative Commons Attribution 4.0 International License.

[1] [01] Associação Brasileira de Normas Técnicas. NBR 8800:2008. Projeto e execução de estruturas de aço e de estruturas mistas aço-concreto de edifícios: Procedimento. Rio de Janeiro, 2008.

[2] [02] Fakury, R.H. (2007). Sobre a revisão da norma brasileira de projeto de estruturas de aço e estruturas mistas de aço e concreto, a NBR 8800. Revista Escola de Minas - REM, Ouro Preto, v. 60, n. 02, p. 233-239. Abr. - Jun. 2007.

[3] [03] American Institute of Steel Construction. ANSI/AISC 360: Specification for Structural Steel Buildings. Chicago, Illinois. 2005.

[4] [04] EN 1994-1-1:2004. Design of composite steel and concrete structures, Part 1-1:General rules and rules for buildings. EUROCODE 4, European Committee for Standardization, 2004.

[5] [05] Johansson, M.; Gylltoft, K.(2001). Structural behavior of slender circular steel-concrete composite columns under various means of load application. Steel and Composite Structures, v.1, n.4, p.393-410.

[6] [06] De Nardin, S.; El Debs, A.L.H.C. (2007). Axial load behaviour of concrete-filled steel tubular columns. Structures and Buildings, v. 160, p. 13-22.

[7] [07] De Nardin, S.; El Debs, A.L.H.C. (2004). Na experimental study of connections between I-beams and concrete filled steel tubular columns. Steel and Composite Structures, v.04, n.04, p. 303-315.

[8] [08] Roeder, C.W.; Cameron, B.; Brown, C.B. (1999). Composite action in concrete filled tubes. Journal of Structural Engineering, ASCE, v.125, n.5, p.477-484. May.

[9] [09] Elremaily, A.; Azizinamini, A. (2002). Behavior and strength of circular concrete-filled tube columns. Journal of Constructional Steel Research. v.58, n.12, p.1567-1591. Dec.

[10] [10] Giakoumelis, G.; Lam, D. (2004). Axial capacity of circular concrete-filled tube columns. Journal of Constructional Steel Research. v.60, n.7, p.1049-1068. July.

[11] [11] Zeghiche, J.; Chaoui, K. (2005). An experimental behaviour of concrete-filled steel tubular columns. Journal of Constructional Steel Research. v.61, n.1, p.53-66. Jan.

[12] [12] Gupta, P.K.; Sarda, S.M.; Kumar, M.S. (2007). Experimental and computacional study of concrete filled steel tubular columns under axial loads. Journal of Constructional Steel Research. v.63, n.2, p.182-193.

[13] [13] Yu, Z.; Ding, F.; Cai, C.S. (2007). Experimental behavior of circular concrete-filled steel tube stub columns. Journal of Constructional Steel Research.v.63, n.2, p.165-174. Feb.

[14] [14] O'Shea, M.D.; Bridge, R.Q. (2000). Design of circular thin-walled concrete filled steel tubes. Journal of Structural Engineering, ASCE, v.126, n.11, p.1295-1303.

[15] [15] American Society for Testing and Materials. (1992). ASTM A370: Standard test methods for tension testing of metallic materials. Philadelphia.

[16] [16] Oliveira, W.L.A. (2008). Análise teórico experimental de pilares mistos preenchidos de seção circular. Tese (Doutorado) - Escola de Engenharia de São Carlos, Universidade de São Paulo, São Carlos.

[17] [17] Faber, M.H.(2006). Risk and Safety in Civil, Surveying and Environmental Engineering, Swiss Federal Institute of Technology, ETHZ, Switzerland.

[18] [18] Ellingwood, B. and Galambos, T.V. (1982). Probability-based criteria for structural design, Structural Safety 1, pp. 15-26.

[19] [19] Melchers, R.E. (1999). Structural Reliability Analysis and Prediction, 2nd edition, John Wiley and Sons, NY.

[20] [20] Beck, A.T. and Rosa, E. (2006). Structural Reliability Analysis Using Deterministic Finite Element Programs", Latin American Journal of Solids and Structures. v.3, p.197-222.

[21] [21] Beck, A. T.(2007) Computer-aided teaching of structural reliability. XXVIII Iberian Latin-American Congress on Computational Methods in Engineering, Porto - Portugal.

[22] [22] prEN 1990: Basis of Structural Design - Annex C: Basis for Partial Factor Design and Reliability Analysis". European Committee for Standardization, Brussels, "Final Draft", 2001.

[23] [23] Beck, A.T. and Doria, A.S. (2008). Reliability Analysis of I-section Steel Columns Designed According to New Brazilian Building Codes, J. of the Braz. Soc. of Mech. Sci. and Eng., Vol. 30, No. 2. p. 152-159.