A non-linear finite element modelling of composite beam to CFST column connection

Abstract

The use of steel and concrete composite structure is increasing day by day especially the use of CFST columns in multistory composite building frames due to the reason that they can significantly reduce overall construction time by eliminating the need of formwork and sometimes even reinforcing bars. However, creating an ideal joint between composite beam and CFST column is quite challenging task from design, analysis and construction point of view. This connection behaviour can best be understood by its moment-rotation curve. So, here attempt has been made to model this composite connection numerically with the software which uses Finite Element Methods as a tool and results are validate. The composite connection possesses all three kinds of non-linearity, that are, geometric, material and boundary/contact nonlinearities. It is known that composite connection is nothing but the combination of bare steel connection and reinforced concrete slab with proper shear transfer mechanism and so first a bare steel connection and reinforced concrete beam is modelled. An explicit representation of connection is not necessary as long as the adequate features are captured. So attempt has been made to optimize the connection where ever it is possible. Usually design engineers design composite structure while neglecting the “composite action”in during the analysis. Sometimes these composite actions contribute much in resisting the applied load.