Impact of Temperature Rise on the Seismic Performance of Concrete-Filled Double Skin Steel Columns with Prismatic Geometry

Abstract

This paper studies the impact of temperature rise on the performance of Concrete-Filled Double Skin Tubular Steel Columns with prismatic geometry. In doing so, several columns whose interior cores were square, diamond, and circularly shaped and whose exterior cores were prismatic with a square cross-sectional area that increases with the slope of 2.1 degrees from top to the bottom, were constructed and exposed to the temperatures of 25°C, 250°C, 500°C, and 700°C. Afterward, all column specimens were subjected to cyclic loads adopted from the Applied Technology Council (ATC)-24 loading protocol, which proceeded until the specimens failed to further carry loads. The results indicate that although the failure modes of the columns with an interior core of a square or diamond shape are similar to each other, the columns whose interior cores were circularly shaped experienced more intensive damages compared to the others. The base of the columns was fractured diagonally with a degree of 45 by the temperature of 500°C, but at 700°C, the damages have occurred horizontally at the height of 10 cm from the column base. Moreover, the initial stiffness and ductility ratio of the columns with a diamond-shaped interior core was approximately two times greater than the other columns.