Performance of Beam Column Joints in Concrete Filled Steel Tubular Frames

Abstract

The use of concrete filled steel tubes (CFST) in building construction has seen renaissance in recent years due to their numerous advantages, apart from their superior structural performance. Their practice as columns in high-rise buildings, as beams in low-rise industrial buildings and as arch bridges, has become widespread in countries like China in past two decades. But unfortunately, their usage in India is a new concept and has hardly seen the light of the day. The focus of this research is to explore the bounties of CFST sections to investigate potential usage in the building industry; mainly considering the structural behaviour. It is widely recognized that innovative use of two or more different materials in a structure usually lead to more efficient system for resisting seismic forces. The CFST structures make an efficient structural system with the advantage of both steel and reinforced concrete frame. It has numerous advantages in terms of structural performance and construction sequence. The concrete in-fill delays inherent buckling problem of thin-walled steel tubes and confinement effect exerted by the steel tube improves their performance. The steel at the outer perimeter performs most effectively in tension and bending enhancing its structural performance. CFST system has all the merits which bring it into the category of sustainable construction system as it reduces the cost of construction in many ways and this helps to save resources. Main focus of the present study is to investigate the behaviour of beam-column joints in CFST frames. Various parameters influencing the behaviour of these columns have been studied. Numerical study of short columns has been carried out by using the experimental data available in literature and the model has been validated by comparison. From the comparison of the experimental results with the results obtained from finite element (FE) model it can be concluded that the proposed FE model is capable of predicting the column behaviour very accurately. It is observed