FRP-Concrete-Steel Double Skin Tubular Cantilever Beams: Behavior under Cyclic Loading
This paper reports on an experimental study on the flexural behavior of fiber reinforced polymer (FRP)-concrete-steel double skin cantilever beams (referred to as DSTBs) that were tested under reversed cyclic loading. The beams were manufactured using a high-strength concrete (HSC) mix and they were 150 mm in diameter and 1.2 m in length. The main parameters of the experimental study included the size of the inner steel tube and the use of mechanical connectors in the form of steel rings welded on the inner steel tube. Test results indicate that DSTBs are capable of developing a highly ductile behavior under reversed cyclic lateral displacement excursions. It is found that the addition of mechanical connectors on the steel tube has no significant influence on the lateral displacement capacity of the test specimens, but they can eliminate the slippage between the concrete and inner steel tube. Examination of the test results has led to a number of significant conclusions on the influence of the beam parameters on the performance of DSTBs, which are discussed in the paper.