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Article
Publication date: 14 August 2017

Venkatesh Kodur and Mohannad Z. Naser

This purpose of this paper is to quantify the effect of local instability arising from high shear loading on response of steel girders subjected to fire conditions.

Abstract

Purpose

This purpose of this paper is to quantify the effect of local instability arising from high shear loading on response of steel girders subjected to fire conditions.

Design/methodology/approach

A three-dimensional nonlinear finite element model able to evaluate behavior of fire-exposed steel girders is developed. This model, is capable of predicting fire response of steel girders taking into consideration flexural, shear and deflection limit states.

Findings

Results obtained from numerical studies show that shear capacity can degrade at a higher pace than flexural capacity under certain loading scenarios, and hence, failure can result from shear effects prior to attaining failure in flexural mode.

Originality/value

The developed model is unique and provides valuable insight (and information) to the fire response of typical hot-rolled steel girder subjected to high shear loading.

Details

PSU Research Review, vol. 1 no. 2
Type: Research Article
ISSN: 2399-1747

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Article
Publication date: 13 March 2017

Venkatesh Kodur, James Stein, Rustin Fike and Mahmood Tabbador

This paper aims to present an evaluation of comparative fire resistance on traditional and engineered wood joists used in the construction of floor systems in residential housing.

Abstract

Purpose

This paper aims to present an evaluation of comparative fire resistance on traditional and engineered wood joists used in the construction of floor systems in residential housing.

Design/methodology/approach

Fire resistance experiments were carried out on four types of wood joists, namely, traditional lumber, engineered I-joist, castellated I-joist and steel/wood hybrid joist, used in traditional and modern residential construction. The test variables included type of wood joist, support conditions and fire protection (insulation).

Findings

Results from these tests indicate that webs of engineered I-joists and castellated I-joists are highly susceptible to fire, and failure generally occurs through the burn-out of the web. In addition, engineered I-joists have much lower fire resistance than traditional solid joist lumber. The application of an intumescent coating on an engineered I-joist significantly enhances its fire resistance and yields a similar level of fire resistance as that of a traditional lumber joist.

Originality/value

The presented fire tests are unique and provide valuable insight (and information) to the behavior and response of four types of wood joists when subjected to gravity loading and fire conditions.

Details

Journal of Structural Fire Engineering, vol. 8 no. 1
Type: Research Article
ISSN: 2040-2317

Keywords

Content available
Article
Publication date: 11 September 2019

Venkatesh Kodur, Puneet Kumar and Muhammad Masood Rafi

The current fire protection measures in buildings do not account for all contemporary fire hazard issues, which has made fire safety a growing concern. Therefore, this…

Abstract

Purpose

The current fire protection measures in buildings do not account for all contemporary fire hazard issues, which has made fire safety a growing concern. Therefore, this paper aims to present a critical review of current fire protection measures and their applicability to address current challenges relating to fire hazards in buildings.

Design/methodology/approach

To overcome fire hazards in buildings, impact of fire hazards is also reviewed to set the context for fire protection measures. Based on the review, an integrated framework for mitigation of fire hazards is proposed. The proposed framework involves enhancement of fire safety in four key areas: fire protection features in buildings, regulation and enforcement, consumer awareness and technology and resources advancement. Detailed strategies on improving fire safety in buildings in these four key areas are presented, and future research and training needs are identified.

Findings

Current fire protection measures lead to an unquantified level of fire safety in buildings, provide minimal strategies to mitigate fire hazard and do not account for contemporary fire hazard issues. Implementing key measures that include reliable fire protection systems, proper regulation and enforcement of building code provisions, enhancement of public awareness and proper use of technology and resources is key to mitigating fire hazard in buildings. Major research and training required to improve fire safety in buildings include developing cost-effective fire suppression systems and rational fire design approaches, characterizing new materials and developing performance-based codes.

Practical implications

The proposed framework encompasses both prevention and management of fire hazard. To demonstrate the applicability of this framework in improving fire safety in buildings, major limitations of current fire protection measures are identified, and detailed strategies are provided to address these limitations using proposed fire safety framework.

Social implications

Fire represents a severe hazard in both developing and developed countries and poses significant threat to life, structure, property and environment. The proposed framework has social implications as it addresses some of the current challenges relating to fire hazard in buildings and will enhance overall fire safety.

Originality/value

The novelty of proposed framework lies in encompassing both prevention and management of fire hazard. This is unlike current fire safety improvement strategies, which focus only on improving fire protection features in buildings (i.e. managing impact of fire hazard) using performance-based codes. To demonstrate the applicability of this framework in improving fire safety in buildings, major limitations of current fire protection measures are identified and detailed strategies are provided to address these limitations using proposed fire safety framework. Special emphasis is given to cost-effectiveness of proposed strategies, and research and training needs for further enhancing building fire safety are identified.

Details

PSU Research Review, vol. 4 no. 1
Type: Research Article
ISSN: 2399-1747

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Article
Publication date: 11 June 2018

Mohannad Naser and Venkatesh Kodur

This paper aims to present results from numerical studies on the response of fire exposed composite girders subjected to dominant flexural and shear loading. A finite…

Abstract

Purpose

This paper aims to present results from numerical studies on the response of fire exposed composite girders subjected to dominant flexural and shear loading. A finite element-based numerical model was developed to trace the thermal and structural response of composite girders subjected to simultaneous structural loading and fire exposure. This model accounts for various critical parameters including material and geometrical nonlinearities, property degradation at elevated temperatures, shear effects, composite interaction between concrete slab and steel girder, as well as temperature-induced local buckling. To generate test data for validation of the model, three composite girders, each comprising of hot-rolled (standard) steel girder underneath a concrete slab, were tested under simultaneous fire and gravity loading.

Design/methodology/approach

The validated model was then applied to investigate the effect of initial geometric imperfections, load level, thickness of slab and stiffness of shear stud on fire response of composite girders.

Findings

Results from experimental and numerical analysis indicate that the composite girder subjected to flexural loading experience failure through flexural yielding mode, while the girders under shear loading fail through in shear web buckling mode. Further, results from parametric studies clearly infer that shear limit state can govern the response of fire exposed composite girders under certain loading configuration and fire scenario.

Originality/value

This paper presents results from numerical studies on the response of fire exposed composite girders subjected to dominant flexural and shear loading.

Details

Journal of Structural Fire Engineering, vol. 9 no. 2
Type: Research Article
ISSN: 2040-2317

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Article
Publication date: 12 December 2016

Ha Nguyen, Ann E. Jeffers and Venkatesh Kodur

This paper aims to address a need for improving the structural resilience to multi-hazard threats including fire and progressive collapse caused by the loss of a column.

Abstract

Purpose

This paper aims to address a need for improving the structural resilience to multi-hazard threats including fire and progressive collapse caused by the loss of a column.

Design/methodology/approach

The focus is on a steel moment frame that uses welded-unreinforced flange-bolted web connections between the beams and columns. A three-dimensional finite element (FE) model was created in ABAQUS with temperature-dependent properties for steel based on the Eurocode. The model was validated against experimental data at ambient and elevated temperature.

Findings

The failure mechanisms in the FE model were consistent with experimental observations. Two scenarios were considered: fixed load with increasing temperature (i.e. simulating column failure prior to fire) and fixed temperature with increasing load (i.e. simulating column failure during fire).

Originality/value

A macro element (or component-based) model was also introduced and validated against the FE model and the experimental data, offering the possibility of analyzing large-scale structural systems with reasonable accuracy and improved computational efficiency.

Details

Journal of Structural Fire Engineering, vol. 7 no. 4
Type: Research Article
ISSN: 2040-2317

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Article
Publication date: 10 September 2018

Hai Yan Zhang, Hao Ran Lv, Venkatesh Kodur and Shu Liang Qi

This paper aims to present performance comparison of fiber sheet-strengthened reinforced concrete (RC) beams bonded with geopolymer and epoxy resin under ambient and fire…

Abstract

Purpose

This paper aims to present performance comparison of fiber sheet-strengthened reinforced concrete (RC) beams bonded with geopolymer and epoxy resin under ambient and fire conditions.

Design/methodology/approach

This study presents experimental results of bending tests at ambient temperature and fire resistance tests on two control beams and eight fiber sheet-strengthened RC beams. The test variables include fiber sheet type (carbon fiber [CF] and basalt fiber [BF] sheet), number of layers of fiber sheet (one and two layers) and adhesive agent type (geopolymers and epoxy resin). Data generated from these tests were used to evaluate and compare the strengthening effectiveness of CF-reinforced polymer (CFRP) and CF-reinforced geopolymer (CFRG) at ambient temperature and under fire exposure conditions.

Findings

Test results clearly show that the CFRG system can provide good strengthening effectiveness on RC beams at ambient temperature, as the CFRP system, owing to excellent bond properties of geopolymers. Although geopolymers possess better bonding properties at high temperature than organic matrix, the strengthened beams bonded with geopolymer do not exhibit better fire resistance than that those bonded with epoxy resin, owing to early falling-off of fire insulation. Thus, in CFRG-strengthened beams, relevant measures are to be taken to minimize falling-off of fire insulation to achieve good fire resistance.

Originality/value

The presented results are from unique fire tests and provide valuable insight (and information) on the performance of fiber sheet-strengthened RC beams bonded with geopolymer and epoxy resin under ambient and fire conditions.

Details

Journal of Structural Fire Engineering, vol. 9 no. 3
Type: Research Article
ISSN: 2040-2317

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Article
Publication date: 14 June 2010

Venkatesh Kodur and Monther Dwaikat

The effect of fire induced restraint on the fire response of reinforced concrete (RC) beams is addressed in this paper. A macroscopic finite element model, capable of…

Abstract

The effect of fire induced restraint on the fire response of reinforced concrete (RC) beams is addressed in this paper. A macroscopic finite element model, capable of tracing the behavior of restrained RC beams from pre-fire stage to collapse in fire is used in the analysis. The model is applied to investigate the effect of five parameters; namely, degree of axial restraint, span-to-depth ratio, fire scenario, load level, and failure criteria on the fire response of restrained RC beams. Through the results of the parametric study, it is shown that the five parameters have significant influence on fire resistance of RC beams. It is also shown that, fire induced restraint has negative effect on fire resistance of slender RC beams having high span-to-depth ratio.

Details

Journal of Structural Fire Engineering, vol. 1 no. 2
Type: Research Article
ISSN: 2040-2317

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Article
Publication date: 23 March 2012

Nikhil Raut and Venkatesh Kodur

A numerical model was developed for tracing the behavior of circular reinforced concrete (RC) columns over the entire range of loading from pre-fire conditions to collapse…

Abstract

A numerical model was developed for tracing the behavior of circular reinforced concrete (RC) columns over the entire range of loading from pre-fire conditions to collapse under fire. The macroscopic finite element based model utilizes time dependant moment-curvature relations of various column segments and the analysis is carried out in three stages; namely, establishing fire temperatures, calculating the heat transfer through the structure, and then carrying out strength analysis. The model, which accounts for high temperature nonlinear material properties, is capable of predicting the fire resistance of circular RC columns under realistic fire scenarios, loading conditions, and failure criteria. The validity of the model is established by comparing predictions from the computer program with results from full-scale fire resistance tests. The validated model is applied to undertake a set of parametric studies to quantify the effect of column size, load level, load eccentricity, and concrete strength on the fire resistance of RC columns. Results generated from parametric studies are utilized to develop a simplified equation for evaluating the fire resistance of circular RC columns. Fire resistance predictions from the proposed equation are in good agreement with those obtained from fire tests and nonlinear finite element analysis.

Details

Journal of Structural Fire Engineering, vol. 3 no. 1
Type: Research Article
ISSN: 2040-2317

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Article
Publication date: 10 December 2013

Aijaz Zende, A. Kulkarni and Aslam Hutagi

This paper reviews the research carried on effects of fire on the mechanical and thermal properties on concrete. Fire in the structure causes higher temperature at the…

Abstract

This paper reviews the research carried on effects of fire on the mechanical and thermal properties on concrete. Fire in the structure causes higher temperature at the concrete surface, which causes a reduction in compressive strength, modulus of elasticity of concrete. Though concrete is a poorer conductor than steel, sustained high temperature at the surface leads to progressive heating of the inner layers of concrete. This leads to exposing reinforcing bars to higher temperature; which causes a reduction in the yield stress, ductility and tensile strength of steel. This paper also focuses on the concrete cover, the reinforcement bars in a concrete structure are protected against fire only by the concrete cover layer thus higher is the cover more is the resistance and vice a versa. Effects of temperature on the thermal conductivity of concrete is also discussed in detail.

Details

Journal of Structural Fire Engineering, vol. 4 no. 4
Type: Research Article
ISSN: 2040-2317

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Article
Publication date: 1 June 1997

Jaroslav Mackerle

Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the…

Abstract

Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical as well as practical points of view. The range of applications of FEMs in this area is wide and cannot be presented in a single paper; therefore aims to give the reader an encyclopaedic view on the subject. The bibliography at the end of the paper contains 2,025 references to papers, conference proceedings and theses/dissertations dealing with the analysis of beams, columns, rods, bars, cables, discs, blades, shafts, membranes, plates and shells that were published in 1992‐1995.

Details

Engineering Computations, vol. 14 no. 4
Type: Research Article
ISSN: 0264-4401

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