Assessment Of Performance-based Requirements For Structural Design

Abstract

The paper presents how actions can be assessed for a performance-based structural fire safety design from the first formulations in the building program to the final derivations of the fire load to be applied for each structural member. In order to indicate what is of importance for the assessment of the requirements, a couple of simple analyses of structural response are made. The examples are chosen deliberately to show the difference between a traditional design based on standard fire resistance and a performance-based approach. A methodology is developed for a decision on the safety level and for a detailed assessment of the requirements. The design requirements to be used for a factory producing elements for industrial housing for unknown costumers are discussed, and a fully developed fire is recommended as a common requirement for domestic houses, hotels, offices, schools and hospitals. In addition it is shown how a fire brigade can be expected to perform in a building designed by means of the methodology.

Evolution of fire models for estimating structural fire-resistance

“…The cooling phase has consistently been demonstrated to be important in terms of structural strength. For example, Hertz performed an experimental study for a fully developed fire scenario and tested the strength concrete column, it was found that load bearing capacity of column decreased by half during flaming phase and other half in cooling phase [51].…”

“…According to Hertz, "safe design" of a structure in terms of fire depends on two important questions: first, if the building is allowed to collapse during fire (which is generally never an acceptable criterion set by a code) or not, second; if the stakeholders rely on the fire brigade [51]. It is through stakeholder agreement that the performance requirements are set.…”

Response to Vytenis Babrauskas “Comments on “The Historical Narrative of the Standard Temperature–Time Heating Curve for Structures” by Gales, et al.”

“…It is noted in Dr. Babrauskas' letter that he views the cool down phase of heating to be a non-problem. The authors would like to highlight that there have been experiments where cool down has been shown to be a vulnerability to structures [11][12][13][14] and also in real structures [15]. The inclusion of the cool down phase acknowledges the delay in heat propagation through materials (including combustible ones), and this allows for a more thorough analysis of the structural behaviour after the peak fire temperatures has been reached.…”