Prediction on ultimate strength of tube-gusset KT-joints stiffened by 1/4 ring plates through experimental and numerical study

One typical joint in steel tube tower, i.e. the tube-gusset KT-joints stiffened by 1/4 ring plates, has been paid attention lately due to its merits about reasonable stress distribution and low cost. But the relevant design theory lags obviously other than design recommendations from JSSC and CIDECT. However they are proved less effective with regard to certain failure mode. For this reason, the paper has proposed one design formula to make up the deficit based on yield line theory. Finally the proposed formula is testified to be more accurate and versatile than other design rules.