Material and structural behaviour of steel and concrete structures at elevated temperatures

• Main Authors: Ting, Seng Kiong., Tan, Kang Hai., Tan, Teng Hooi., Phng, Eugene Guan Hwee.
• Other Authors: School of Civil and Environmental Engineering
• Format: Research Report
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Civil engineering::Structures and design
• Online Access: http://hdl.handle.net/10356/17235
• Institution: Nanyang Technological University

A programme of experimental testing has been conducted to investigate the behaviour of steel columns and concrete-encased steel section composite columns at elevated temperature. Heating is attained in an electric furnace. Measurements of internal forces, lateral deflections, axial displacements and temperatures are reported. Twenty steel column specimens were subjected to elevated temperatures. One loading test was carried out at ambient temperature to determine the working load to be applied to the other specimens in the same series for elevated temperature tests. The variable parameters were slenderness ratio and axial restraint ratio. The experimental measurements are presented and compared with predictions from numerical simulations using FEMFAN-3D, a program developed by NTU. It is concluded that buckling temperature decreases as slenderness ratio increases, under a fixed restraint ratio. Applying increased axial restraint to the columns has a negative effect of reducing the buckling temperatures. Eleven composite column tests were conducted under elevated temperature conditions. The composite columns were categorised into three series with different variable parameters, namely overall cross-sectional size, load ratio and axial restraint ratio. Results show that the fire resistance of composite column improves with an increase in overall cross–sectional size. An increase in load ratio or axial restraint ratio will lead to a reduction in its fire resistance. Test results are compared with FEMFAN-3D predictions for verifying the accuracy of the program. Column behaviour under elevated temperatures and predictions and limitations of the numerical program FEMFAN are discussed in the report.