AISC 360-16 and EC4 approaches for concrete filled steel tube stub columns

Composite members are used widely in civil engineering structures. The steel and concrete act together to resist the loads. Composite columns are a significant application of composite construction, and the Concrete-Filled Steel Tube (CFST) columns are the most common type of composite columns. Circular CFST column provides much more effective confinement to the core concrete than other types of column sections under axial load due to an enhancement of composite action between steel tube and core concrete. Many design specifications are used to predict the capacity of CFST columns, such as AISC 360–16 and the Eurocode 4. The AISC 360–16 is the specification for steel structures in the United States; the Eurocode 4 is the European code for composite structure design, respectively. The objective of this thesis is to investigate the differences between the AISC 360-16 and the Eurocode 4 approaches of circular CFST columns under axial load and to evaluate how well they model the actual column behavior through a series of statistical comparisons. Also, the parameters which are used in design specification calculations steps will be assessed. The important parameters in calculations will also be specified to underline the appropriate way in the design field. In present study, A total of 256 column models, where various structural parameters were varied to investigate their combined effect: concrete compressive strength fc' taken as 30 MPa, 50 MPa, 70 MPa and 90 MPa were considered as ranged to cover normal and high strength concrete, steel tube yield strength fy varied as 235 MPa, 315 MPa, 395 MPa and 475 MPa to cover mild and high tensile strength steel, D/t ratio taken as 20, 40, 60 and 80, and L/D ratio taken as 3, 6, 9 and 12 to cover short and long column with constant diameter of the composite column as 200 mm.