Structural Performance Evaluation of CFT Columns with Built-up Square-shaped Steel Tubes using Production Methods

Abstract

This study obtained compression test results and macro examination results for concrete-filled steel tube (CFT) columns with built-up square-shaped steel tubes to evaluate both the structural performance and the possibility of using the current CFT design for changes in production methods. The CFT columns have three variables, namely, welding details, welding types, and steel bar types, of which welding details are the main variable. The compression test results were compared with the nominal compressive strength, Pn, based on the material test results and complete joint penetration (CJP). The test results indicated that the ratio of the experimental maximum load to the theoretical calculation result was between 1.04 and 1.12 (1.08 on average). This means that it is possible to use the current CFT design in the current Building Structure Standards (KBC 2016, KDS 41 31 00). The macro examination results indicated that the quality of welding will be improved owing to the minimization of defects during welding if the groove angle is improved to 50°.