Finite element modeling of concrete confined with circular thin-walled steel sheet

Abstract

For a reinforced concrete column to behave in a ductile manner without much loss on strength requires sufficient confinement to the concrete core. One way to provide confinement to the concrete core is to use external confining devices such as a series of thin-walled circular steel sheet tube to confine the concrete. This type of external confining device falls off on the categories of Steel Tube Confined Concrete (STCC). With the presence of a gap between the steel sheet, the buckling on the tube due to high axial stresses can be avoided. On the other hand, STCC also offers great advantages to strengthen a non-code conforming reinforced concrete column to achieve better resistance to withstand earthquake load. From the numerical analysis point of view, the important task to successfully model the STCC specimen lies in the modeling of the interface behavior between concrete and steel tube. For that purpose, in this paper, the 3D-NLFEA package is used to study the response of STCC. The analysis result is further compared with the available test results in the literature. From the analysis, the predicted response is excellent. Detailed discussion on the parameter of the interface behavior between concrete and steel tube is presented.