Advanced Steel Construction

Vol. 6, No. 3, pp. 879-890 (2010)



G.J. van der Vegte 1, * and Y. Makino 2

1 Delft University of Technology, Faculty of Civil Engineering and Geosciences,

Section GCC – Stevin II Lab., Stevinweg 1, 2628 CN Delft, The Netherlands

2 Department of Architecture and Civil Engineering, Kumamoto University,

Kurokami 2-39-1, Kumamoto 860-8555, Japan

*(Corresponding author: E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.)

Received: 1 October 2009; Revised: 29 January 2010; Accepted: 5 February 2010




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In the past many questions existed regarding the effect of the chord length and boundary conditions on the static strength of tubular joints. In addition to previous research by van der Vegte (1995), the current study focuses on the numerical analyses of axially loaded X-joints with the chord length parameter α, the brace-to-chord diameter ratio β, the chord thickness ratio 2γgand the chord end conditions (i.e. free versus fully restrained chord ends) being the major variables. Based on finite element (FE) results, the effect of the chord length and the boundary conditions on the static strength of the X-joints considered is presented. The results are briefly compared with (i) van der Vegte’s previous data (1995) on X-joints and (ii) the chord length effect found for CHS T-joints by van der Vegte and Makino (2006). It is concluded that the influence of boundary conditions can be much more pronounced than originally anticipated. Hence, in designing test specimens or re-evaluating experiments conducted in the past, special attention should be given to these issues in order to prevent the chord length and boundary conditions having a significant influence on the results.



Tubular joint; circular hollow section; T-joint; X-joint; finite element analysis; chord length; boundary conditions


[1]       Connelly, L.M. and Zettlemoyer, N., “Frame Behaviour Effects on Tubular Joint Capacity”, Proceedings 3rd International Symposium on Tubular Structures, Lappeenranta, Finland, 1989, pp. 81-89.

[2]       Bolt, H.M., Seyed-Kebari, H. and Ward, J.K., “The Influence of Chord Length and Boundary Conditions on K-Joint Capacity”, Proceedings 2nd International Offshore and Polar Engineering Conference, San Francisco, USA, 1992, Vol. IV, pp. 347-354.

[3]       Choo, Y.S., Qian, X.D. and Wardenier, J., “Effects of Boundary Conditions and Chord Stresses on Static Strength of Thick-Walled CHS K-Joints”, Journal of Constructional Steel Research, 2006, Vol. 62, No. 4, pp. 316-328.

[4]       Vegte, G.J. van der and Makino, Y., “Ultimate Strength Formulation for Axially Loaded CHS Uniplanar T-Joints”, International Journal of Offshore and Polar Engineering, ISOPE, 2006, Vol. 16, No. 4, pp. 305-312.

[5]       MARC Analysis Research Corporation, Revision K4, Palo Alto, USA, 1990.

[6]       Voth, A.P. and Packer, J.A., “Branch Plate Connections to Round Hollow Sections”, CIDECT Report 5BS-5/08, 2008.

[7]       Vegte, G.J. van der, “The Static Strength of Uniplanar and Multiplanar Tubular T- and X-Joints”, Doctoral Dissertation, Delft University of Technology, the Netherlands, ISBN 90-407-1081-3, Delft University Press, the Netherlands, 1995.

[8]       Vegte, G.J. van der, Koning, C.H.M de, Puthli, R.S. and Wardenier, J., “Numerical Simulation of Experiments on Multiplanar Tubular Steel X-Joints”, International Journal of Offshore and Polar Engineering, ISOPE, 1991, Vol. 1, No. 3, pp. 200-207.

[9]       ABAQUS/Standard, Version 6.3, Hibbitt, Karlsson and Sorensen, Inc, USA, 2003.

[10]     American Welding Society, Structural Welding Code, AWS D1.1-92, 1992.

[11]     Scola, S., Redwood, R.G. and Mitri, H.S., "Behaviour of Axially Loaded Tubular V-Joints”, Journal of Constructional Steel Research, 1990, Vol. 16, No. 2, pp. 89-109.

[12]     Vegte, G.J. van der, Wardenier, J., Zhao, X.-L. and Packer, J.A., “Evaluation of New CHS Strength Formulae to Design Strengths”, Proceedings of the 12th International Symposium on Tubular Structures, Shanghai, China, 2008, pp. 313-322.