Han, Li and Liao 2011
Experimental Study and Results
This paper discusses testing on concrete-filled double skin steel tubes (CFDSTs), under long-term loading conditions. The testing is split into two stages: long-term service test, and ultimate strength test. 6 tests were performed and were comprised of 2 circular and 2 square CFDSTs, and 2 CFT’s for reference under concentric loading. Furthermore, 10 CFDST and CFT were used for reference and comparison in terms of the ultimate loads. In order to test the specimens, the bars were pre-stressed, and the long-term load test was performed for three years. It was seen that the strain increased under long-term sustained loads until about 1 month, and then increased much more slowly, and stabilised after 100 days. During the ultimate strength test, all members exhibited buckling
Analytical Study and Discussions
A finite element model using a ABAQUS software with 4-node shell elements and 8-node brick elements were used for the steel and concrete, respectively. Another fibre based method was used to predict long-term behavior for the CFDST columns under long sustained loading. Both of these studies were used to create a simplified model..
Han, L., Li, Y., and Liao, F. (2011). “Concrete-Filled Double Skin Steel Tubular (CFDST) Columns Subjected to Long-Term Sustained Loading.” Thin-Walled Structures, 49 (12), December, pp. 1534–1543. doi:10.1016/j.tws.2011.08.001