Abstract
This report represents the study on the optimum rib shape for the concrete-filled structural steel pipe, and also the study on the rolling method of the hot-rolled strip. The pipe with inner ribs is developed for the composite foundation pipes consisted of steel pipe and filled-concrete in order to get sure bond stress capacity between pipe and filled-concrete. The bond stress capacity tests indicate that the value of rib height divided by rib space is the most essential parameter and the value of 0.1 gives the optimum rib shape. Next, the characteristics of rolling of the rib-strip are studied by experiments with many longitudinal ribs distributed throughout the strip width. The experimental results show that the rib height depends on not only reduction but also the caliber profiles and entry thickness. Based on the experiments, the hot rolling method of the strip with 3.0 mm height ribs on the average is established.
