Similar articles

Abstract: Recent research has shown that circular hollow section (CHS) joints may exhibit non-rigid behavior under axial load or bending. The non-rigid behavior significantly affects the mechanical performance of structures. This paper is concerned with the parametric formulae for predicting axial stiffness of CHS X-joints while braces are in tension. The factors influencing the axial stiffness of CHS X-joints under brace axial tension are investigated, including the joint geometric parameters, the axial force of the chord, and bending moments of braces in two directions, etc. Effects of various parameters on axial stiffness of CHS X-joints are examined by systematic single-parameter nonlinear analysis using shell finite element methods. The analysis is implemented in a finite element code, ANSYS. The observed trends form the basis of the formulae for calculating the joint axial stiffness under brace axial tension by multivariate regression technique. In order to simplify the formulae, two non-dimensional variables are introduced. The proposed formulae can be used to calculate the joint axial stiffness in the design of single-layer steel tubular structures.

[1]Chen, T.Y., Zhang, H.Y., 1996. Stress analysis of spatial frames with consideration of local flexibility of multiplanar tubular joint. Engineering Structures, 18(6):465-471.

[2]Chen, Y.Y., Wang, W., Zhao, X.Z., Jiang, X.Y., Bai, X., Zhao, Z.Y., 2001. Experiments on bending rigidity and resistance of unstiffened tubular joints. Journal of Building Structures, 22(6):25-30 (in Chinese).

[3]Choo, Y.S., Qian, X.D., Liew, J.Y.R., Wardenier, J., 2003. Static strength of thick-walled CHS X-joints. Part II. Effect of chord stresses. Journal of Constructional Steel Research, 59(10):1229-1250.

[4]Choo, Y.S., Qian, X.D., Wardenier, J., 2006. Effects of boundary conditions and chord stresses on static strength of thick-walled CHS K-joints. Journal of Constructional Steel Research, 62(4):316-328.

[5]GB 50017-2003. Code for Design of Steel Structures. Chinese Standard. Chinese Plan Press, Beijing, China (in Chinese).

[6]Gho, W.M., Yang, Y., 2008. Parametric equation for static strength of tubular circular hollow section joints with complete overlap of braces. Journal of Structural Engineering, 134(3):393-401.

[7]Gho, W.M., Yang, Y., Gao, F., 2006. Failure mechanisms of tubular CHS joints with complete overlap of braces. Thin-Walled Structures, 44(6):655-666.

[8]Ihaddoudenea, A.N.T., Saidani, M., Chemrouka, M., 2009. Mechanical model for the analysis of steel frames with semi rigid joints. Journal of Constructional Steel Research, 65(3):631-640.

[9]Lopez, A., Puente, I., Serna, M.A., 2007. Numerical model and experimental tests on single-layer latticed domes with semi-rigid joints. Computers and Structures, 85(7-8):360-374.

[10]Qian, X., Dodds, R.H., Choo, Y.S., 2005. Elastic-plastic crack driving force for tubular X-joints with mismatched welds. Engineering Structures, 27(9):1419-1434.

[11]Qiu, G.Z., Zhao, J.C., 2008. Experimental research on rigidity of circular tubular X-joints. Journal of Shanghai Jiaotong University, 42(6):966-970 (in Chinese).

[12]Qiu, G.Z., Zhao, J.C., 2009. Analysis and calculation of axial stiffness of tubular X-joints under compression on braces. Journal of Shanghai Jiaotong University (Science), 14(4):410-417.

[13]Qiu, G.Z., Zhao, J.C., 2010. Influence of joint stiffness on stability behavior of a single-layer reticulated shell. Building Structure, 40(3):97-99, 117 (in Chinese).

[14]SAS, 2002. ANSYS User’s Manual, Revision 6.1. Swanson Analysis Systems, Inc., PA, USA.

[15]Schumacher, A., Borges, L.C., Nussbaumer, A., 2009. A critical examination of the size effect correction for welded steel tubular joints. International Journal of Fatigue, 31(8-9):1422-1433.

[16]Shu, X.P., Zhu, S.N., Xia, X.H., Yang, X., 2004. Full-scale experiment research on CHS joints of steel roof of He Long Stadium in Changsha. Journal of Building Structures, 25(3):11-13 (in Chinese).

[17]Soh, C.K., Chan, T.K., Yu, S.K., 2000. Limit analysis of ultimate strength of tubular X-joints. Journal of Structural Engineering, 126(7):790-797.

[18]Turker, T., Kartal, M.E., Bayraktar, A., 2009. Assessment of semi-rigid connections in steel structures by modal testing. Journal of Constructional Steel Research, 65(7):1538-1547.

[19]Wang, W., 2005. Non-Rigid Behavior of Unstiffened Circular Tubular Joints and Their Effects on Global Performance of Steel Tubular Structures. PhD Thesis, Tongji University, Shanghai, China (in Chinese).

[20]Wang, W., Chen, Y.Y., 2005. Modeling and classification of tubular joint rigidity and its effect on the global response of CHS lattice girders. Journal of Structural Engineering and Mechanics, 21(6):677-698.

[21]Yang, L.X., Chen, T.Y., Wu, S.Y., 1990. Local flexibility behavior of tubular joints and its effect on global analysis of tubular structures. China Ocean Engineering, 4(4):371-384.