In recent years, concrete-filled box columns (CFBCs) have been commonly used in high-rise buildings. In particular, steel box columns filled with high-performance concrete (HPC) are more common than concrete-encased steel columns. However, a number of fire test results show that there are significant differences between HPC and normal concrete after being subjected to high temperatures. Therefore, the residual strength of HPC-filled box columns exposed to fire was determined in this study. Two groups of full-size specimens were fabricated. The specimen of the control group was loaded at room temperature to achieve its ultimate load. On the other hand, fire tests were carried out on three specimens of the experimental group to investigate their residualload-bearing capacity after exposure to elevated temperatures (400, 600, and 800 °C). To monitor and measure the temperature of the CFBC specimens during the fire test, an appropriate number of thermocouples were buried inside and outside the column. The thermocouples can effectively measure the temperature of the CFBC specimens during the fire test. The test results show that the residual ultimate strength of CFBC specimens increased at 400 and 600 °C by 5.2 and 1.0% respectively, compared with room-temperature strength. However, with a further increase in temperature to 800 °C, the residual ultimate strength was 15.7% lower than that of the control group at room temperature.
In this study, a series of two full-scale experiments were carried out to investigate the effects of welding method on the fire resistance of concrete-filled box columns (CFBCs). The column specimens were all square sections 500 × 500 mm 2 in size and 4350 mm high and were filled with high-strength concrete. Specimen CP1 was fabricated by a complete penetration weld while specimen PP1 was fabricated by a partial penetration weld. The tested columns were subjected to a constant compression load throughout the test period. The applied load corresponded to 28% of the design value of the buckling resistance of the column at room temperature. Test results indicate that the fire resistance of specimen CP1 was 55 min, compared with 51 min for specimen PP1. As a result, it can be concluded that under a load level of 0.28, the effect of different welding methods on the fire resistance of CFBC was not very significant. In addition, the established numerical model was able to reasonably predict the axial deformation of the tested columns.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.