Seminar - Zhong Tao - Post-fire bond between the steel tube and concrete in concrete-filled steel columns

Wednesday 11 May 2011, 4.00 pm - 5.00 pm
Civil Engineering Conference Room

Associate Professor Zhong Tao
School of Engineering
University of Western Sydney

Abstract:
Concrete-filled steel tubular (CFST) columns have been used widely in many countries in recent decades. The exposure of CFST members to fire can lead to significant loss of strength and stiffness. No research, however, has been conducted so far concerning their post-fire bond behaviour. An assessment of the degree of deterioration of the bond in CFST columns after exposure to fire can help engineers to evaluate the reliability of the load transfer between the steel tube and concrete at various locations if necessary.

Push-out tests were carried out on sixty four CFST columns, which had been exposed to ISO 834 standard fire for 90 min or 180 min, respectively. The variables investigated were selected as (a) fire exposure time; (b) cross-section type; (c) cross-sectional dimension; (d) interface length to diameter (or width) ratio; (e) concrete type; (f) fly ash type; and (g) concrete curing condition. The effects of the above different parameters on the bond behaviour are discussed. The test results indicate that fire exposure had a significant effect on the bond between a steel tube and its concrete core. A decrease in bond strength was generally observed for specimens after a fire exposure of 90 min; however, a recovery of bond strength was found when the fire exposure time was extended to 180 min. Other factors also had influence to some extent.


Biography
Associate Professor Zhong Tao obtained his PhD at Harbin Institute of Technology in 2001 in China. Zhong is currently one of Australia’s first Future Fellows, awarded by the Federal Government in September 2009. He is now working as an Associate Professor to carry out this Future Fellowship at the University of Western Sydney (UWS). Before joining UWS, Zhong held a position of Professor at Fuzhou University, China. Zhong has a research background in the area of steel-concrete composite structures. He has supervised over 40 higher degree research students, and published two books, 36 international journal papers and 69 Chinese journal papers.