To fire resistance of the steel and fibre-reinforced concrete circular hollow section column

This study predicts the shear strength of steel fibre reinforced concrete (SFRC) members at elevated temperature using numerical modelling. The authors derived the stress-strain relation in the pure shear mode at ambient temperature based on a damage model calibrated at ambient and elevated temperatures. The model was validated on the special experimental arrangement for the pure shear mode of the SFRC in torsion. These results enables to determine the stress-strain diagram at elevated temperature. The shear strength of SFRC is compared with the compressive and tensile strength and used to observe reasons for experimentally observed failure model. The work is a part of comprehensive project focused on development of design models for the steel and SFRC composite columns with circular hollow section (CHS) at elevated temperature. Research includes two levels accuracy/complexity, allowing simplified or advanced approach to design following the coming changes in European standard for composite member design in fire, EN1994-1-2:2021. Experimental studies of the project include mechanical material tests of heated fibre-concrete samples in tension and compression, thermal uniform and non-uniform tests of insulated fragments of CHS and tests of full scale SFRC CHS columns in steady-state and transient-state regimes. Developing advanced FEM simulation of global mechanical behaviour of SFRC CHS columns is a multi-levelled composite mechanical and thermo-model and provide numerous numerical experiments. Together with steel material model in fire, validated FEM model of mechanical behaviour of fibre-reinforce concrete at elevated temperature is performed. Validated simplified and advanced thermal model of SFRC in CHS at elevated temperature gives temperature fields and moisture distribution inside section which depends on direction, heat flux, sizes and gives possibility to model different fire cases of full-scale columns in bending, shear, and buckling at elevated temperature. Proposed analytical and simplified FEM mechanical model of column is taking into account degradation of mechanical properties, analytical models of transfer of heat inside the column section and provides simple solutions for designers.

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Experimental Study on Limiting Temperatures of Circular Hollow Sections

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.472-475.1206 ◽

2012 ◽

Vol 472-475 ◽

pp. 1206-1214 ◽

Cited By ~ 3

Author(s):

In Kyu Kwon ◽

Heung Youl Kim ◽

Hyung Jun Kim

Keyword(s):

Fire Resistance ◽

Simple Method ◽

Hollow Section ◽

Steel Columns ◽

Steel Members ◽

Fire Condition ◽

And Performance ◽

Circular Hollow Section ◽

Limiting Temperatures ◽

Fire Design

Fire resistance is required to sustain the structural stability when building elements are exposed to a severe fire condition. To evaluate the fire resistance of structural members such as columns and beams, fire engineers can apply either prescriptive methods or performance-based fire design. These two kinds of fire resistance evaluation methods have been developed independently and performance fire design consists mainly of an advanced and simple methods. The simple method stipulated in New Zealand and the U.K. use the limiting temperature. The values of the limiting temperatures of structural steel members were shown in the BS, SNZ, etc but the temperatures of individuals were not classified. In general steel columns were made of H-section but recently the hollow section is inclined to increase for its higher resistant of structural stabilities than any other sections. But the hollow section shows different pattern when it carry out the loads in the cold and is expected to show different behavior when it is exposed to fire. Therefore the limiting temperature of the hollow section is required for evaluation of fire resistance. The paper is to make the limiting temperature of the circular hollow section (CHS) with or without filling of concrete and variance of applied loads.

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Evaluation of fire resistance of rectangular steel columns filled with fibre-reinforced concrete

Canadian Journal of Civil Engineering ◽

10.1139/l96-114 ◽

1997 ◽

Vol 24 (3) ◽

pp. 339-349 ◽

Cited By ~ 23

Author(s):

VKR Kodur ◽

T T Lie

Keyword(s):

Reinforced Concrete ◽

Fire Resistance ◽

Fibre Reinforced Concrete ◽

Steel Columns

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Thermal and mechanical properties of steel-fibre-reinforced concrete at elevated temperatures

Canadian Journal of Civil Engineering ◽

10.1139/l96-055 ◽

1996 ◽

Vol 23 (2) ◽

pp. 511-517 ◽

Cited By ~ 75

Author(s):

T. T. Lie ◽

V. K. R. Kodur

Keyword(s):

Mechanical Properties ◽

Thermal Properties ◽

Reinforced Concrete ◽

Fire Resistance ◽

Elevated Temperatures ◽

Steel Fibre ◽

Fibre Reinforced Concrete ◽

Thermal And Mechanical Properties ◽

Steel Fibre Reinforced Concrete ◽

Deformation Properties

For use in fire resistance calculations, the relevant thermal and mechanical properties of steel-fibre-reinforced concrete at elevated temperatures were determined. These properties included the thermal conductivity, specific heat, thermal expansion, and mass loss, as well as the strength and deformation properties of steel-fibre-reinforced siliceous and carbonate aggregate concretes. The thermal properties are presented in equations that express the values of these properties as a function of temperature in the temperature range between 0 °C and 1000 °C. The mechanical properties are given in the form of stress–strain relationships for the concretes at elevated temperatures. The results indicate that the steel fibres have little influence on the thermal properties of the concretes. The influence on the mechanical properties, however, is relatively greater than the influence on the thermal properties and is expected to be beneficial to the fire resistance of structural elements constructed of fibre-reinforced concrete. Key words: steel fibre, reinforced concrete, thermal properties, mechanical properties, fire resistance.

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Fibre Cocktail to Improve Fire Resistance

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.711.480 ◽

2016 ◽

Vol 711 ◽

pp. 480-487

Author(s):

György L. Balázs ◽

Olivér Czoboly

Keyword(s):

Experimental Study ◽

Reinforced Concrete ◽

Flexural Strength ◽

High Temperatures ◽

Fire Resistance ◽

Fibre Reinforced Concrete ◽

Cellulose Fibres ◽

Cold State

Favourable experience with fibre reinforced concrete (FRC) resulted in its increasing use worldwide. The properties of fibre reinforced concrete are mostly influenced by the type and the amount of fibres. Our experimental study was directed to the possible improvements of the residual flexural strength and the properties of concrete exposed to high temperatures with different fibre cocktails including steel, micro polymer or cellulose fibres. The influence of type and amount of fibres on residual flexural strength in cold state were tested after 300, 500 or 800 °C temperature loading.

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