Experimental Behavior and Design of CFT-RC Short Columns Subjected to Concentric Axial Loading

Concrete-filled steel tube (CFT)-RC composite members consist of multiple CFT columns connected by RC plates or webs. CFT-RC composite members have been used in different types of structures, for example, as ribs in long-span arch bridges and as tall piers supporting long-span bridges. However, there is limited knowledge regarding their fundamental axial load-displacement behavior, and a general lack of behavior-based design equations for estimating their axial compressive strength. This paper addresses these knowledge gaps by presenting experimental results from axial loading tests conducted on 14 short (stub) column specimens. These include seven CFT-RC columns, four CFT columns, and three RC plates. The parameters included in the tests are the thickness of the steel tube wall (t(s)) and RC plates (t(p)). An experimental database of 104 CFT column tests conducted around the world is also compiled. The experimental results from the tests conducted in this research are combined with those from the compiled database and used together to develop behavior-based design equations for estimating the axial compressive strength of short CFT-RC columns. (C) 2017 American Society of Civil Engineers.