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A Numerical Model for Predicting the Fire Resistance of Reinforced Concrete Beams

Journal Title, Volume, Page: 
Cement and Concrete Composites Volume 30, Issue 5, Pages 431–443
Year of Publication: 
2008
Authors: 
M. Dwaikat
Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824-1126, United States
Current Affiliation: 
Building Engineering Department, Faculty of Engineering and Information Technology, An-Najah National University, Nablus, Palestine
V.K.R. Kodur
Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824-1126, United States
Preferred Abstract (Original): 

A numerical model, in the form of a computer program, for tracing the behavior of reinforced concrete (RC) beams exposed to fire is presented. The three stages associated with the numerical procedure for evaluating fire resistance of RC beams; namely, fire temperature calculation, thermal analysis and strength analysis, are explained. A simplified approach to account for spalling under fire conditions is incorporated into the model. The use of the computer program for tracing the response of RC beams from the initial pre-loading stage to collapse stage, due to the combined effect of fire and loading, is demonstrated. The validity of the numerical model is established by comparing the predictions from the computer program with results from full-scale fire resistance tests. Through the results of numerical study, it is shown that the type of failure criterion has significant influence on predicting the fire resistance of RC beams.

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Performance-Based Fire Safety Design of Reinforced Concrete Beams

Journal Title, Volume, Page: 
Journal of Fire Protection Engineering, Vol. 17, No. 3, pp. 293-320
Year of Publication: 
2007
Authors: 
M. Dwaikat
Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824-1126, USA
Current Affiliation: 
Building Engineering Department, Faculty of Engineering and Information Technology, An-Najah National University, Nablus, Palestine
V.K.R. Kodur
Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824-1126, USA
Preferred Abstract (Original): 

A numerical model, in the form of a computer program, is presented for tracing the fire behavior of reinforced concrete (RC) beams over the entire range of loading from pre-fire conditions to collapse under fire. The three stages associated with the analysis of fire resistance; namely, establishing the fire temperature—time development, calculating the heat transfer through the structure from the fire, and the structural analysis are explained. The model, which accounts for nonlinear material properties at elevated temperatures, is capable of predicting the fire resistance of RC beams under realistic fire scenarios, load levels, and failure criteria. The validity of the numerical model is established by comparing the predictions from the computer program with results from full-scale fire resistance tests. Through the results of numerical study, it is shown that the type of failure criterion, load level, and fire scenario have significant influence on fire resistance of RC beams. The computer program can be used to undertake performance-based fire safety design of RC beams for any value of the significant parameters, such as fire exposure, concrete cover thickness, section dimensions, concrete strength, concrete type, and load intensity.

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A Numerical Approach for Modeling the Fire Induced Restraint Effects in Reinforced Concrete Beams

Journal Title, Volume, Page: 
Fire Safety Journal Volume 43, Issue 4, Pages 291–307
Year of Publication: 
2008
Authors: 
M.B. Dwaikat
Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824-1126, USA
Current Affiliation: 
Building Engineering Department, Faculty of Engineering and Information Technology, An-Najah National University, Nablus, Palestine
V.K.R. Kodur
Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824-1126, USA
Preferred Abstract (Original): 

In this paper, a model to predict the influence of fire induced restraints on the fire resistance of reinforced concrete (RC) beams is presented. The three stages, associated with the fire growth, thermal and structural analysis, for the calculation of fire resistance of the RC beams are explained. A simplified approach to account for spalling under fire conditions is incorporated into the model. The validity of the numerical model is established by comparing the predictions from the computer program with results from full-scale fire resistance tests. The program is used to conduct two case studies to investigate the influence of both the rotational and the axial restraint on the fire response of the RC beams. Through these case studies, it is shown that the restraint, both rotational and axial, has significant influence on the fire resistance of the RC beams.

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Effect of Fire Induced Restraint on Fire Resistance of Reinforced Concrete Beams

Journal Title, Volume, Page: 
Journal of Structural Fire Engineering, Vol. 1, No.2, pp. 73-88
Year of Publication: 
2009
Authors: 
Monther B. Dwaikat
An-Najah National University, Nablus, Palestine
Current Affiliation: 
Building Engineering Department, Faculty of Engineering and Information Technology, An-Najah National University, Nablus, Palestine
Venkatesh K. R. Kodur
SAFE-D Center, Dept. of Civil & Environ Engineering, Michigan State University
Preferred Abstract (Original): 

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

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Macroscopic FE Model for Tracing the Fire Response of Reinforced Concrete Structures

Journal Title, Volume, Page: 
Engineering Structures Volume 31, Issue 10, Pages 2368–2379
Year of Publication: 
2009
Authors: 
Monther Dwaikat
Department of Civil & Environmental Engineering, Michigan State University, East Lansing, MI 48824-1126, United States
Current Affiliation: 
Building Engineering Department, Faculty of Engineering and Information Technology, An-Najah National University, Nablus, Palestine
Venkatesh Kodur
Department of Civil & Environmental Engineering, Michigan State University, East Lansing, MI 48824-1126, United States
Nikhil Raut
Department of Civil & Environmental Engineering, Michigan State University, East Lansing, MI 48824-1126, United States
Preferred Abstract (Original): 

A macroscopic finite element model for tracing the fire response of reinforced concrete (RC) structural members is presented. The model accounts for critical factors that are to be considered for performance-based fire resistance assessment of RC structural members. Fire induced spalling, various strain components, high temperature material properties, restraint effects, different fire scenarios and failure criteria are incorporated in the model. The validity of the numerical model is established by comparing the predictions from the computer program with results from full-scale fire resistance tests. Case studies are conducted to demonstrate the use of the computer program for tracing the response of RC members under standard and design fire exposures. Through the results of the case studies, it is shown that the fire scenario has a significant effect on the fire resistance of RC columns and beams. It is also shown that macroscopic finite element models are capable of predicting the fire response of RC structural members with an adequate accuracy for practical applications.

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