A parametric study of hotspot stresses in multiplanar tubular XT-joints has been conducted in which 180 finite element analyses were performed. The study covers a wide range of joint geometries under various combinations of axial forces. The results of the analyses are presented as a set of equations expressing the stress concentration factor as a function of the relevant geometric parameters for various combinations of axial forces. A typical full-size steel multiplanar XT-joint was selected for experimental testing to verify the numerical analyses. A comparison is also made between the results obtained for multiplanar tubular XT-joints and those of the corresponding uniplanar T- and X-joints. It is found that, when all the braces of the multiplanar XT-joints are loaded simultaneously, the multiplanar effect is significant. When the out-of-plane braces are not loaded, the multiplanar effect is insignifcant for small â value when the comparison is made between the multiplanar XT-joints with uniplanar T-joints.
S.P. Chiew, Professor C.K. Soh, A.K. Soh, T.C. Fung and W.M. Lee