Han and Yan 2000

From Composite Systems
Jump to: navigation, search

An experimental study was conducted on slender columns. Both CFT and hollow steel tube columns were tested. The test results were compared with Chinese design code provisions.

Experimental Study Results and Discussions

Eleven circular CFT columns and four circular HT columns were tested monotonically under axial load. The specimens had slenderness ratios ranging from 130 to 154. The D/t ratio for each specimen was equal to 24. The L/D ratio ranged between 32.5 and 38.5. Two kinds of concrete mix were used. One of them had a measured cubic compressive strength of 4.6 ksi and the other one had a measured cubic compressive strength of 6.8 ksi. The measured yield strength of steel tube for all the specimens was 50.5 ksi. Simply supported end conditions were simulated by the test setup.

All the specimens exhibited relatively ductile behavior. For the hollow tube columns, the local buckling occurred at an earlier stage than the CFT columns. This showed that the concrete infill increased the local buckling strength. Both hollow tube columns and CFT columns failed at the mid-height by the rupture of the steel tube wall. The steel tube wall rupture took place either at the tension region following extensive concrete cracking or at the compression region due to local buckling. The capacities of the CFT specimens were found to be up to 30% higher than the capacities of the hollow tube specimens. However, there was not any significant difference between the strengths of the CFT columns filled with different kinds of concrete.

The capacities of the tested columns were also calculated using the Chinese design code provisions. They were compared with the experimental findings and the corresponding design code method was found to be conservative.

References

Han, L.-H. and Yan, S.-Z. (2000). “Experimental Studies on the Strength with High Slenderness Ratio Concrete Filled Steel Tubular Columns,” Composite and Hybrid Structures, Proceedings of the Sixth ASCCS International Conference on Steel-Concrete Composite Structures, Xiao, Y. and Mahin, S. A. (eds.), Los Angeles, California, March 22-24, 2000, Association for International Cooperation and Research in Steel-Concrete Composite Structures, Los Angeles, California, pp. 419-426.