Abstract
Concrete filled tubular (CFT) frames have been widely applied in high-rise buildings since the early 1990s. However, there is a need to seek more cost-effective connection details, and this is especially true for square tubes. To meet this need, a relatively simple and cost-saving solution, in which a connection is stiffened with two interior T-shaped diaphragms, was experimentally investigated. This connection detail has been long used for steel frames; however, its application to the CFT frames has been limited because of the lack of information on the behavior and design guidelines. Based on the test results and observations obtained through this research, strength models and design formulas were derived using a limit analysis technique. Comparison with the test results showed that the proposed formulas provided accurate strength estimates.
