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Keywords: steel structures, tubular joints, nonlinear analysis, finite element method.

Summary

The use of steel hollow sections has significantly increased in steel structures around the world and especially in Portugal due to their mechanical and aesthetical properties. Most sections adopted are the rectangular hollow sections (RHS) and the circular hollow sections (CHS).

The need for an analytical approach review to predict the behaviour of these structures is a very important subject, especially when the behaviour of the connections between their members is considered. The common analytical approach used in Portugal to design these structures is the Eurocode 3 - Part 1.8 (EC3) [1]. In this paper, a parametric analysis is performed and a comparison between numerical and analytical results is investigated. The analytical results were obtained using the EC3 approach for SHS "T" joints subjected to tension in the brace.

These types of connections present a minor axis behaviour which is characterized by an initial stiffness and a resistance reserve after failure called membrane stiffness. The main characteristic of these connections is that there are no points which indicate the failure of the connection because the force-displacement (F-delta) curve presents a smooth form. Some existing methods to estimate the connection resistance using the (F-delta) curve are given.

The numerical model developed to perform this study was conceived with the finite element software ANSYS [2] using shell elements. In this model the weld and the root radius were also simulated. A material and geometric non-linear analysis was performed. The model was validated using the results obtained by Lie et al. [3]. A parametric study was accomplished with forty-two numerical simulations.

In this study the (F-delta) curves were obtained for different connection geometries. The main conclusion obtained with this investigation was that both connection resistance and initial stiffness increase with the increase of beta and/or the decrease of gamma values.

Another conclusion is related to values of beta<=0.8 where the resistance obtained from the numerical model is very similar to the analytical one. But above this beta value, there is an increase in the difference between numerical and analytical results. This shows that the analytical expressions for failure modes for beta>=0.8 should be reviewed as well as the application of the value of maximum displacement of 3%b₀ for beta>=0.8.

References

1: EUROCODE 3. EN 1993-1-8, "Design of steel structures Part 1.8: Design of joints", Brussels, CEN-European Committee for Standardisation, 2005.
2: ANSYS 10.0®, ANSYS - Inc. Theory Reference, 2005.
3: S. Lie, S. Chiew, C. Lee, Z. Yang, "Static strength of cracked square hollow section T joints under axial loads. I: Experimental", Journal of Structural Engineering, 132(3), 368-377, 2006. doi:10.1061/(ASCE)0733-9445(2006)132:3(368)

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Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Proceedings ISSN 1759-3433 CCP: 91 PROCEEDINGS OF THE TWELFTH INTERNATIONAL CONFERENCE ON CIVIL, STRUCTURAL AND ENVIRONMENTAL ENGINEERING COMPUTING Edited by: B.H.V. Topping, L.F. Costa Neves and R.C. Barros Paper 1 Evaluation of the Resistance of RHS "T" Joints under Axial Loading: A Parametric Study R.M.M.P. de Matos¹, L.F. Costa-Neves², L.R.O. de Lima³, J.G. Santos da Silva⁴ and P.C.G. da S. Vellasco³ ¹Civil Engineering Department ²ISISE, Civil Engineering Department University of Coimbra, Pólo II, Portugal ³Structural Engineering Department ⁴Mechanical Engineering Department Faculty of Engineering, State University of Rio de Janeiro, Brazil doi:10.4203/ccp.91.1 purchase the full-text of this paper Full Bibliographic Reference for this paper R.M.M.P. de Matos, L.F. Costa-Neves, L.R.O. de Lima, J.G. Santos da Silva, P.C.G. da S. Vellasco, "Evaluation of the Resistance of RHS "T" Joints under Axial Loading: A Parametric Study", in B.H.V. Topping, L.F. Costa Neves, R.C. Barros, (Editors), "Proceedings of the Twelfth International Conference on Civil, Structural and Environmental Engineering Computing", Civil-Comp Press, Stirlingshire, UK, Paper 1, 2009. doi:10.4203/ccp.91.1 Keywords: steel structures, tubular joints, nonlinear analysis, finite element method. Summary The use of steel hollow sections has significantly increased in steel structures around the world and especially in Portugal due to their mechanical and aesthetical properties. Most sections adopted are the rectangular hollow sections (RHS) and the circular hollow sections (CHS). The need for an analytical approach review to predict the behaviour of these structures is a very important subject, especially when the behaviour of the connections between their members is considered. The common analytical approach used in Portugal to design these structures is the Eurocode 3 - Part 1.8 (EC3) [1]. In this paper, a parametric analysis is performed and a comparison between numerical and analytical results is investigated. The analytical results were obtained using the EC3 approach for SHS "T" joints subjected to tension in the brace. These types of connections present a minor axis behaviour which is characterized by an initial stiffness and a resistance reserve after failure called membrane stiffness. The main characteristic of these connections is that there are no points which indicate the failure of the connection because the force-displacement (F-delta) curve presents a smooth form. Some existing methods to estimate the connection resistance using the (F-delta) curve are given. The numerical model developed to perform this study was conceived with the finite element software ANSYS [2] using shell elements. In this model the weld and the root radius were also simulated. A material and geometric non-linear analysis was performed. The model was validated using the results obtained by Lie et al. [3]. A parametric study was accomplished with forty-two numerical simulations. In this study the (F-delta) curves were obtained for different connection geometries. The main conclusion obtained with this investigation was that both connection resistance and initial stiffness increase with the increase of beta and/or the decrease of gamma values. Another conclusion is related to values of beta<=0.8 where the resistance obtained from the numerical model is very similar to the analytical one. But above this beta value, there is an increase in the difference between numerical and analytical results. This shows that the analytical expressions for failure modes for beta>=0.8 should be reviewed as well as the application of the value of maximum displacement of 3%b₀ for beta>=0.8. References 1 EUROCODE 3. EN 1993-1-8, "Design of steel structures Part 1.8: Design of joints", Brussels, CEN-European Committee for Standardisation, 2005. 2 ANSYS 10.0®, ANSYS - Inc. Theory Reference, 2005. 3 S. Lie, S. Chiew, C. Lee, Z. Yang, "Static strength of cracked square hollow section T joints under axial loads. I: Experimental", Journal of Structural Engineering, 132(3), 368-377, 2006. doi:10.1061/(ASCE)0733-9445(2006)132:3(368) purchase the full-text of this paper (price £20) go to the next paper return to the table of contents return to the book description purchase this book (price £140 +P&P)
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