scholarly journals Experimental investigations on the load bearing behaviour of an innovative prestressed composite floor system in fire

2018 ◽  
Author(s):  
Patrick Meyer ◽  
Peter Schaumann ◽  
Martin Mensinger ◽  
Suet Kwan Koh
Keyword(s):  
Fire Resistance ◽  
Large Scale ◽  
Concrete Slab ◽  
Experimental Investigations ◽  
Load Bearing ◽  
Natural Fire ◽  
Fire Scenario ◽  
Standard Fire ◽  
Hollow Space ◽  
Floor System

In Germany, regulations for hollow spaces in slab systems require 30 minutes standard fire resistance of the load-bearing steel construction. Within a current national research project a natural fire scenario for the hollow space was developed based on realistic fire loads and ventilation conditions in the hollow space. Assuming this realistic fire scenario in the hollow space, two large scale tests on an innovative composite floor system were performed to evaluate the influence on the load bearing behaviour of the floor system. The integrated and sustainable composite floor system consists of a prestressed concrete slab, an unprotected, bisected hot rolled I-profile with composite dowels either in puzzle or clothoidal shape, and removable floor panels on the top of the I-profile. This floor system ensures the opportunity to adjust the technical building installations in accordance with the use of the building. This integrated and sustainable composite floor system was developed in several research projects. The standard fire resistance R90 for the fire scenario below the slab system has already been proven successfully. In this paper, experimental investigations regarding the heating and load bearing behaviour of the innovative composite floor system under the newly developed natural fire scenario of hollow spaces are presented. In doing so, the special test set-up to realise the fire tests for the fire scenario hollow space will be described in detail. After the fire scenario for the hollow space, the specimen was subjected to the ISO standard fire curve to establish the failure temperature of the unprotected I-profile. In addition to the temperature development and the load bearing behaviour inside the innovative floor during the heating phase, the cooling phase and the influence of a web opening on the load bearing behaviour will be discussed.

Experimental study on fire resistance of a full-scale composite floor assembly in a two-story steel framed building

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Lisa Choe ◽  
Selvarajah Ramesh ◽  
Xu Dai ◽  
Matthew Hoehler ◽  
Matthew Bundy
Keyword(s):  
Natural Gas ◽  
Fire Resistance ◽  
Full Scale ◽  
System Level ◽  
Compartment Fire ◽  
Content Type ◽  
Standard Fire ◽  
Fire Experiment ◽  
The Usa ◽  
Floor System

PurposeThe purpose of this paper is to report the first of four planned fire experiments on the 9.1 × 6.1 m steel composite floor assembly as part of the two-story steel framed building constructed at the National Fire Research Laboratory.Design/methodology/approachThe fire experiment was aimed to quantify the fire resistance and behavior of full-scale steel–concrete composite floor systems commonly built in the USA. The test floor assembly, designed and constructed for the 2-h fire resistance rating, was tested to failure under a natural gas fueled compartment fire and simultaneously applied mechanical loads.FindingsAlthough the protected steel beams and girders achieved matching or superior performance compared to the prescribed limits of temperatures and displacements used in standard fire testing, the composite slab developed a central breach approximately at a half of the specified rating period. A minimum area of the shrinkage reinforcement (60 mm2/m) currently permitted in the US construction practice may be insufficient to maintain structural integrity of a full-scale composite floor system under the 2-h standard fire exposure.Originality/valueThis work was the first-of-kind fire experiment conducted in the USA to study the full system-level structural performance of a composite floor system subjected to compartment fire using natural gas as fuel to mimic a standard fire environment.

scholarly journals Pipe-concrete columns of buildings and their fire-resistance determination

2018 ◽  
Vol 196 ◽  
pp. 02011
Author(s):  
Nikolay Ilyin ◽  
Nadezhda Kondratyeva ◽  
Vasily Zaiko
Keyword(s):  
Fire Resistance ◽  
Field Tests ◽  
Concrete Columns ◽  
New Method ◽  
Statistical Quality Control ◽  
Resistance Level ◽  
Natural Fire ◽  
Method Of Calculation ◽  
Standard Fire ◽  
Metal Pipes

The research recognizes the necessity of developing a new method of calculation of pipe-concrete columns fire-resistance. It is important for expending the area of their application in construction of buildings and structures; in unique structures as well. The authors apply a simplified mathematical description of the process of pipe-concrete columns resistance to the standard fire effect. This method helps to increase the accuracy of fire resistance level determination to expand these constructions use. If buildings materials are rationally combined, it is possible to produce reliable and sufficiently fireproof structures. Pipe-concrete columns which are, in fact, metal pipes filled with concrete can serve as an example of such structures. Nowadays, field tests are used to determine pipe-concrete constructions fire resistance. The authors introduce a methodology of theoretical determination of pipe-concrete columns fire resistance limit. The use of the proposed methodology makes it possible to reduce labor and economic costs while determining buildings resistance with the use of the pipe-concrete. It opens a possibility of pipe-concrete structures reasonable application in construction practice. The use of this new method allows us to determine pipe-concrete columns fire resistance without resorting to natural fire. It also increases the accuracy of statistical quality control and non-destructive tests. The calculations made in this study as well as previous tests conducted by other researches prove that there is no need for additional fire protection of pipe-concrete columns.

Fire resistance of composite slabs with steel deck under natural fire

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Paulo A.G. Piloto ◽  
Carlos Balsa ◽  
Felipe Macedo Macêdo Gomes ◽  
Bergson Matias
Keyword(s):  
Fire Resistance ◽  
Numerical Models ◽  
Three Dimensional ◽  
Composite Slab ◽  
Content Type ◽  
Natural Fire ◽  
Fire Scenario ◽  
Composite Slabs ◽  
Cooling Phase ◽  
Steel Deck

PurposeMost of the numerical research and experiments on composite slabs with a steel deck have been developed to study the effect of fire during the heating phase. This manuscript aims to describe the thermal behaviour of composite slabs when submitted to different fire scenarios, considering the heating and cooling phase.Design/methodology/approachThree-dimensional numerical models, based on finite elements, are developed to analyse the temperatures inside the composite slab and, consequently, to estimate the fire resistance, considering the insulation criteria (I). The numerical methods developed are validated with experimental results available in the literature. In addition, this paper presents a parametric study of the effects on fire resistance caused by the thickness of the concrete part of the slab as well as the natural fire scenario.FindingsThe results show that, depending on the fire scenario, the fire resistance criterion can be reached during the cooling phase, especially for the thickest composite slabs. Based on the results, new coefficients are proposed for the original simplified model, proposed by the standard.Originality/valueThe developed numerical models allow us to realistically simulate the thermal effects caused by a natural fire in a composite slab and the new proposal enables us to estimate the fire resistance time of composite slabs with a steel deck, even if it occurs in the cooling phase.

scholarly journals Fire resistance of extruded hollow-core slabs

2017 ◽  
Vol 8 (3) ◽  
pp. 324-336 ◽  
Author(s):  
Kristian Hertz ◽  
Luisa Giuliani ◽  
Lars Schiøtt Sørensen
Keyword(s):  
Bearing Capacity ◽  
Fire Resistance ◽  
Hollow Core ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Content Type ◽  
Standard Fire ◽  
Comprehensive Test ◽  
Building Components ◽  
First Time

Purpose Prefabricated extruded hollow-core slabs are preferred building components for floor structures in several countries. It is therefore important to be able to document the fire resistance of these slabs proving fulfilment of standard fire resistance requirements of 60 and 120 min found in most national building regulations. The paper aims to present a detailed analysis of the mechanisms responsible for the loss of load-bearing capacity of hollow-core slabs when exposed to fire. Design/methodology/approach Furthermore, it compares theoretical calculation and assessment according to the structural codes with data derived from a standard fire test and from a thorough examination of the comprehensive test documentation available on fire exposed hollow-core slabs. Findings Mechanisms for loss of load-bearing capacity are clarified, and evidence of the fire resistance is found. Originality value For the first time, the mechanisms responsible for loss of load-bearing capacity are identified, and test results and calculation approach are for the first time applied in accordance with each other for assessment of fire resistance of the structure.

A comparison between CFD and thermal-structural analysis of structural steel members subjected to fire

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Muhannad R. Alasiri ◽  
Mustafa Mahamid
Keyword(s):  
Fire Resistance ◽  
Elevated Temperatures ◽  
Flame Height ◽  
Steel Beams ◽  
Content Type ◽  
Fire Scenario ◽  
Standard Fire ◽  
Cfd Models ◽  
Fire Scenarios ◽  
Astm E119

Purpose Standard fire resistance curves such as ASTM E119 have been used for so long in structural fire practice. The issue with use of these curves that they do not represent real fire scenarios. As a result, the alternatives have been to either conduct experiments or find other tools to represent a real fire scenario. Therefore, the purpose of this paper is to understand the temperature effects resulted from a designed fire on steel beams and whether the standard fire curves represent a designed fire scenario. Design/methodology/approach Computational fluid dynamics (CFD) models were developed to simulate a designed fire scenario and to understand the structural responses on the beams under elevated temperatures. Consequently, the results obtained from the CFD models were compared with the results of three-dimensional (3D) non-linear finite element (FE) models developed by other researchers. The developed FE models were executed using a standard fire curve (ASTM E119). A parametric study including two case studies was conducted. Findings Results obtained from performing this study showed the importance of considering fire parameters such as fuel type and flame height during the thermal analysis compared to the standard fire curves, and this might lead to a non-conservative design as compared to the designed fire scenario. The studied cases showed that the steel beams experienced more degradation in their fire resistance at higher load levels under designed fires. Additionally, the models used the standard fire curves underestimated the temperatures at the early stages. Originality/value This paper shows results obtained by performing a comparison study of models used ASTM E119 curve and a designed fire scenario. The value of this study is to show the variability of using different fire scenarios; thus, more studies are required to see how temperature history curves can be used to represent real fire scenarios.

Concrete Exposed to Fire: From Fire Scenario to Structural Response

2016 ◽  
Vol 711 ◽  
pp. 556-563 ◽  
Author(s):  
Francesco Pesavento ◽  
Matteo Pachera ◽  
Pierfrancesco Brunello ◽  
Bernhard A. Schrefler
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Concrete Slab ◽  
Pressure Rise ◽  
Engineering Practice ◽  
Collapse Mechanism ◽  
Thermal Loads ◽  
Current Form ◽  
Fire Scenario ◽  
Standard Fire

In this paper a model for the analysis of concrete structures exposed to fire, based on Porous Media Mechanics, is coupled with a computational fluid dynamics model. To show the capability of this strategy the numerical simulation of a simple concrete slab exposed to fire is presented. The thermal loads as well as the moisture exchange between the structure surface and the environment are calculated by means of computational fluid dynamics program. Thanks to this strategy the structural verification is no longer based on the standard fire curves commonly used in the engineering practice, but it is directly related to a realistic fire scenario. With the simple example proposed, it is possible to highlight how the localized thermal load generates a non-uniform pressure rise in the material, which results in an increase of the structure stress state and of the spalling risk. Spalling is likely the most dangerous collapse mechanism for a concrete structure. Numerical results of various sections of the slab exposed to fire are presented, showing the effects of a more realistic distribution of the thermal loads with respect to the ones obtained by using the standard fire curves. This coupling approach still represents a “one way” strategy, i.e. realized without considering explicitly the exchange of boundary conditions from the structure to the fluid. This results in an approximation, but from physical point of view the current form of the solid-fluid coupling is considered sufficiently accurate in this first phase of the research.

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