Hollow structural steel (HSS) columns filled with concrete offer a number of benefits and are often used in tall buildings and other industrial structures. A mathematical model was developed and used to investigate the influence of important parameters that determine the fire resistance of concrete-filled hollow steel columns. The behavior of concrete-filled HSS columns with or without fire protection subjected to axial or eccentric loads was experimentally investigated and the results presented in this paper. The parametric and experimental studies provide information for the development of formulas for the calculation of the fire resistance and fire protection thickness of the composite columns. The main objectives of this work were threefold: First, to report a series of fire tests on composite columns; second, to analyze the influence of several parameters, such as the sectional dimension, load eccentricity ratio, and fire protection thickness on the fire resistance of the composite columns. It was fo...

Experimental Study and Calculation of Fire Resistance of Concrete-Filled Hollow Steel Columns

This paper presents a nonlinear local bond-slip model for fiber reinforced polymer (FRP) laminates externally bonded to concrete at elevated temperature for future use in the theoretical modeling of fire resistance of FRP-strengthened concrete structures. The model is an extension of an existing two-parameter bond-slip model for FRP-to-concrete interfaces at ambient temperature. The two key parameters employed in the proposed bond-slip model, the interfacial fracture energy, Gf, and the interfacial brittleness index, B, were determined using existing shear test data of FRP-to-concrete bonded joints at elevated temperature. In the interpretation of test data, the influences of temperature-induced thermal stress and temperature-induced bond degradation are properly accounted for. As may be expected, the interfacial fracture energy, Gf, is found to be almost constant initially and then starts to decrease when the temperature approaches the glass transition temperature of the bonding adhesive; the int...

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Bond-Slip Model for FRP Laminates Externally Bonded to Concrete at Elevated Temperature

Bond characteristics of CFRP plated concrete members under elevated temperatures

http://spiral.imperial.ac.uk/bitstream/10044/1/50897/6/Gardner%20and%20Ng%20%282006%29%20-%20Temperature%20development%20in%20structural%20stainless%20steel%20sections.pdf

Temperature development in structural stainless steel sections exposed to fire

The last two decades have seen increasing applications of fibre reinforced polymer (FRP) materials in civil engineering structures due to their many advantages over traditional strengthening and reinforcing materials Among the most common applications is bonding or wrapping FRP products (strips or sheets) to the exterior of reinforced concrete (RC) members to increase their strength or deformability However, widespread application of FRP strengthening systems in buildings, where structural fire ratings are required, is hindered due to unknowns surrounding the reduction in their mechanical and bond properties at elevated temperatures This paper presents a state-of-the-art review on the fire performance of FRP-strengthened RC structural elements The review addresses first the mechanical behaviour at high temperature of the constituent materials of FRPs and how their bond to concrete is affected when heated The paper then discusses available experimental and numerical studies on the fire behaviour of FRP-strengthened RC beams, slabs, and columns Available design guidance is also discussed Finally, recommendations for future research are given

Fire behaviour of FRP-strengthened reinforced concrete structural elements: A state-of-the-art review

Epoxy adhesive used to form the bond between carbon fibre reinforced polymer (CFRP) and concrete is very sensitive to temperature variations. In general the bond properties deteriorate rapidly with exposure to high temperatures. This paper addresses some of the issues relevant to the performance of the bond at elevated temperatures. The experimental program was done using shear test method. The bond strength was measured at increasing epoxy temperatures. Rapid loss of strength was apparent when epoxy temperature increased beyond 60 o C.

Performance of cfrp strengthened concrete members under elevated temperatures

https://isiarticles.com/bundles/Article/pre/pdf/25704.pdf

Sensitivity analysis of heat transfer formulations for insulated structural steel components

A numerical method, with which experimental results were processed, was adopted to measure the total emissivity of mild steel specimens at high temperatures. This method is derived from considering the transient thermal energy equilibrium between a steel specimen and its surrounding heating environment. As a first step to validate this method, the results obtained at a low temperature were compared with those using infrared thermographic techniques, and a good correlation of 87% was achieved. The numerical model was then extended to high temperatures to investigate the variation of emissivity of steel with temperatures. The convective heat transfer coefficient used in the numerical model was examined in great detail using results obtained from transient high temperature tests. The emissivity of steel obtained from this study shows that steel emissivity varies over a range of temperatures and the variation becomes more abrupt between 400 and 500°C. Formulation for the emissivity of steel at rising ...

https://researchbank.swinburne.edu.au/file/1c4081e5-f04d-4ede-aae8-78a6228facc3/1/PDF (Accepted manuscript).pdf

Man-Biu Bill Wong

Papers

Bond characteristics of CFRP plated concrete members under elevated temperatures

Performance of cfrp strengthened concrete members under elevated temperatures

Sensitivity analysis of heat transfer formulations for insulated structural steel components

Determination of Steel Emissivity for the Temperature Prediction of Structural Steel Members in Fire

Modelling of axial restraints for limiting temperature calculation of steel members in fire