Study on behaviour of cast steel K-joints in circular hollow sections

Circular hollow sections are commonly used in steel industry and many types of joints like T, K, X etc., are encountered during the construction phase. The joints can be connected using weld or bolt assembly. In this paper, an attempt is made to study the response of K joints using cast steel nodes when subjected to quasi-static cyclic loading. Eight specimens are fabricated and connected using steel nodes to form K-joints and are tested under quasi-static cyclic loading. From the experimental study, ultimate failure load under tension and compression, mode of failure, hysteresis curve and load deflection envelope are determined. The load values obtained are compared with design strength values of welded K-joint and longitudinal gusset plate connected T-joint specimens as predicted by AISC and CIDECT guidelines. The study reveals that cast steel nodes can be used as an alternative for connecting joints and the strength obtained is slightly higher than that predicted with longitudinal gusset plate connected T-jointed specimens.