Behaviour of Beam-Column Subjected to Reversed Lateral Loading

This paper presents an experimental investigation on the behaviour of Concrete Filled Double Skin Tubular (CFDST) column connected to Concrete Filled Steel Tubular (CFST) beam under reversed lateral loading. The CFDST column consists of two concentric cold-formed steel tubes with concrete sandwiched between them and the CFST member consist of cold-formed steel hollow section completely filled with concrete. The specimen in this study consists of a hollow square tube as the outer skin for both CFDST and CFST members. The inner skin of the CFDST column is a circular steel tube and M30 grade concrete having 40% cement replaced with fly ash was filled in between the tubes. The connection between the beams and the columns were provided using through bolts and angle plates. A pair of specimens considered as the control specimens having CFST members for both beam and column were also tested for comparison. All the four specimens were subjected to a constant axial load and reversed lateral loading which simulates the earthquake forces. The seismic characteristics like hysteretic behavior, peak load displacement, ductility, stiffness degradation and energy dissipation of CFDST beam-column were compared with that of the CFST beam-column. The beam-column specimens with CFDST columns exhibited favorable seismic behaviour with reduced self-weight and hence a better choice than CFST columns in regions of seismic risk.