On Quantification of Error and Uncertainty in Two-zone Models used in Fire                 Safety Design

Lundin, Johan

doi:10.1177/0734904105049172

Cited by 15 publications

(9 citation statements)

References 11 publications

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“…The simulation of a fire in a compartment is a complex phenomenon that is commonly simplified to two independent parts; first, the method by which the temperature produced by the fire is accounted for ( T gas ) and, second, the actual boundary condition that needs to be applied to the structural element. For the former, several parametric models have been developed to calculate the temperatures produced by a fire in a compartment (Remesh and Tan, ; Lundin, ). These models are established either using ‘time–temperature curve’ methods—sometimes called ‘standard fire’—such as those mentioned in ISO 834 International Standard (), and ASTM E119 () (based on experiment and tests) or using ‘natural fire’ models that rely mainly on the volume of the produced gas by the combustible materials in a space such as those stated in SEI/ASCE ().…”

Section: Methodsmentioning

confidence: 99%

Post‐earthquake fire resistance of CFRP strengthened reinforced concrete structures

Behnam

Ronagh

2013

Structural Design Tall Build

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SUMMARY Post‐earthquake fire (PEF) presents a high risk to buildings that have been partially damaged in a prior earthquake, particularly in urban areas. As most standards and criteria ignore the possibility of fire after earthquake, buildings are not adequately designed for that possibility, and thus, PEF is a high‐risk load needed to be scrutinized further, codified and become part of a routine design. An investigation based on sequential analysis inspired by FEMA356 is performed here on two RC frames, of three and five stories, at the Life Safety performance level and designed to the ACI 318‐08 code, after they have been subjected to a spectral peak ground acceleration of 0.35 g. A fire analysis of the weakened structures follows, from which the time it takes for the damaged structures to collapse is determined. As a point of reference, the fire resistance is also determined for undamaged structures and before the occurrence of earthquake. The results show that structures previously damaged by the earthquake and exposed to PEF are considerably more vulnerable than those that have not been damaged previously. A method using carbon fiber‐reinforced polymer as a means of relocation of plastic hinges away from the column faces towards the beams is introduced as a function of the time required for fire extinguishment or evacuation. This is carried out to increase the structural load‐carrying capacity, thus reducing the potential damage for the anticipated earthquake and thereby improve the PEF resistance. The results show a considerable improvement in the PEF resistance of the frames. While the investigation and the proposition relate to a certain class of structures (ordinary buildings, intermediate RC structures, three and five stories) and the results can therefore be applied only to the cases investigated, it is hoped that this study paves the way for further research into this very important phenomenon and leads to an eventual revision of codes. Copyright © 2013 John Wiley & Sons, Ltd.

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Section: Methodsmentioning

confidence: 99%

Post‐earthquake fire resistance of CFRP strengthened reinforced concrete structures

Behnam

Ronagh

2013

Structural Design Tall Build

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“…It has been found that the error varies both within a scenario and between different scenarios [3]. From a practical standpoint, it is crucial to reduce the complexity of adjusting for the error.…”

Section: Model Error In Two-zone Modelsmentioning

confidence: 99%

“…Since there is no generally accepted protocol for addressing uncertainties in model predictions with a quantified approach, the quantitative approach must be regarded as one of several recognized tools. Another objective is to evaluate whether the statistical analysis model, presented in depth by Lundin [3], is appropriate for this purpose.…”

Section: Objectivesmentioning

confidence: 99%

Quantifying Error and Uncertainty in CFAST 2.0 Temperature Predictions

Lundin

2005

Journal of Fire Sciences

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In this paper the predictive capability of the smoke transport model CFAST 2.0 is evaluated for five different scenario configurations. The evaluation is made by statistical analysis according to a methodology presented in an earlier paper. Model predictions and experimental data, previously published, are compared and quantitative measures of the predictive capability are thus derived. With the quantitative knowledge of the model error, future predictions from the two-zone model can be adjusted so that the error is taken into account. The suitable method of adjustment depends on how the uncertainty is treated in a specific application. This can be done either by using conservative adjustments or by treating the uncertainty in the predictions as a stochastic variable. The evaluation shows that the statistical method is applicable for this purpose and that reduction of the model error can be achieved with the adjustment model for the types of scenarios subject to analysis.

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“…Several methods have been developed to calculate the thermal actions produced by a fire in a compartment (Lundin, ; Remesh and Tan, ). These methods have been established either using parametric fires called ‘time–temperature curves’, such as those mentioned in ISO834 (ISO 834 International Standard, ) and American Society for Testing and Materials (ASTM) E119 (ASTM, ) and based mainly on experiment and tests or using ‘natural fires’, which rely mainly on the volume of gas produced by the combustible materials in a covered space, such as those stipulated in the American Society of Civil Engineers or ASCE ().…”

Section: Computational Proceduresmentioning

confidence: 99%

Behavior of moment‐resisting tall steel structures exposed to a vertically traveling post‐earthquake fire

Behnam

Ronagh

2013

Structural Design Tall Build

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SUMMARY An investigation is performed on a 10‐story moment‐resisting steel structure designed to the Life Safety level of performance of the Federal Emergency Management Agency (FEMA) 356 code by exposing it to post‐earthquake fire (PEF). The fire curve is accounted for using the natural fire method, and the fire is subjected to the floors vertically in three different scenarios: (a) fire initiated from the first floor, (b) fire initiated from the fourth floor and (c) fire initiated from the seventh floor. A delay of 5 minutes and 25 minutes are considered for spreading the fire between the floors. To make a comparison between the results, a concurrent fire is also considered for the fire analysis. The results indicate that the PEF resistance of the frame exposed to the concurrent fire and the 5 minutes delay is much lower than that with a delay of 25 minutes. The results also show that subjecting the frame to a delayed fire of 25 minutes leads to the collapse of the frame during cooling phase, whereas in the other scenarios, the frame collapses during heating phase. As a result, more considerations need to be implemented in the codes on top of that for the PEF itself and that is the appropriate rate of spread of fire between floors. Copyright © 2013 John Wiley & Sons, Ltd.

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On Quantification of Error and Uncertainty in Two-zone Models used in Fire Safety Design

Cited by 15 publications

References 11 publications

Post‐earthquake fire resistance of CFRP strengthened reinforced concrete structures

Post‐earthquake fire resistance of CFRP strengthened reinforced concrete structures

Quantifying Error and Uncertainty in CFAST 2.0 Temperature Predictions

Behavior of moment‐resisting tall steel structures exposed to a vertically traveling post‐earthquake fire

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