Concrete filled steel tube column and method of constructing same

Abstract

A concrete filled steel tube column which includes: a steel tube connected to beams of a structure so that an axial compressive load is transferred from the beams to the steel tube; and a concrete core, disposed within the steel tube, for bearing an axial compressive load transferred from the beams via the steel tube to the concrete core. The steel tube has a plurality of prestressed tube pieces concentrically joined in series. Each of these tube pieces has an axial prestress introduced into it to counteract a stress resulting from the compressive load applied to the steel tube. With this arrangement, substantially no axial stress is induced in the steel tube. In constructing the column, a steel tube piece is erected, and beams are joined to the tube piece. An axial tensile load is applied to the tube piece so that an axial stress is induced in the tube piece. After the application of the load, concrete is charged into the tube piece. After the concrete is cured, the tensile load is released from the tube piece so that the concrete core is subjected to an axial compression as a reaction to the application of an axial tension to the tube piece. Another tube piece is coaxially joined to an upper end of the concrete filled tube piece. Thereafter, the above-mentioned steps from the beam-joining step to the tube piece-joining step are repeated a plurality of times.