scholarly journals REACTION OF R/C SLABS CROSS-SECTIONS TO FIRE, Calculation of simplified substitute temperature loads induced by an unsteady heat flow

2016 ◽  
Author(s):  
Robert Kowalski ◽  
Marian Abramowicz ◽  
Paweł Chudzik
Keyword(s):  
Reinforced Concrete ◽  
Temperature Distribution ◽  
Heat Flow ◽  
Cross Sections ◽  
Average Temperature ◽  
Standard Fire ◽  
Reinforced Concrete Slabs ◽  
Nonlinear Temperature ◽  
Advanced Analysis ◽  
Temperature Loads

<p>An important issue in advanced analysis of reinforced concrete structures exposed to fire is to determine the response of structural elements (cross-sections) to the effect of high temperature. The unsteady heat flow results in a nonlinear temperature distribution. In practical structural calculations performed by simplified computer programs the average temperature value and the appropriate temperature gradient are used. This paper presents substitute values of these parameters and detailed analysis of nonlinear temperature distribution in 20, 25, 30 cm thick reinforced concrete slabs exposed to one-sided standard fire.</p>

scholarly journals Determination of features of composite steel and concrete slab behavior under fire condition

2021 ◽  
Vol 6 (7 (114)) ◽  
Author(s):  
Valeriia Nekora ◽  
Stanislav Sidnei ◽  
Taras Shnal ◽  
Olga Nekora ◽  
Iryna Dankevych ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Temperature Distribution ◽  
Fire Resistance ◽  
Temperature Regime ◽  
Strain State ◽  
Concrete Slabs ◽  
Standard Temperature ◽  
Steel Reinforced Concrete ◽  
Steel Sheets ◽  
Reinforced Concrete Slabs

Methods for calculating the fire resistance of steel-reinforced concrete slabs made using profiled steel sheets under the influence of a standard temperature regime for more than 120 minutes are considered and analyzed. Research has been carried out to determine the heating parameters and the stress-strain state of steel-reinforced concrete slabs made using profiled steel sheets under fire conditions for more than 120 minutes. The results of this study allow to obtain indicators of temperature distribution for assessing the fire resistance of such structures for fire resistance classes above REI 120. Accordingly, the results obtained are a scientific basis for improving the existing method for calculating the fire resistance of steel-reinforced concrete slabs made using profiled steel sheets. The temperature distribution in the cross-section of structures was obtained using a general theoretical approach to solving the problem of heat conduction using the finite element method. Using the obtained temperature distributions, the parameters of the stress-strain state were determined based on the method of limiting states. To carry out the calculations, appropriate mathematical models were created that describe the effect of the standard temperature regime of a fire, to determine the temperature distribution at every minute in the sections of steel-reinforced concrete slabs with profiled steel sheets. A method is proposed for dividing the section into zones to take into account the decrease in the indicators of the mechanical properties of concrete and steel. A simplified method for the design assessment of steel-reinforced concrete slabs made using profiled steel sheets is proposed, which is consistent with the current EU standards and can be effectively used to analyze their fire resistance when establishing their compliance with the fire resistance class REI 120 and higher.

scholarly journals Does the design according to the seismic zone affect the environment and the manufacturing cost of a 5-storey R/C building with a conventional plan?

2021 ◽  
Vol 899 (1) ◽  
pp. 012032
Author(s):  
Theodoros Chrysanidis ◽  
Athina Gkigki ◽  
Grigorios Papageorgiou ◽  
Nikolaos Alamanis
Keyword(s):  
Reinforced Concrete ◽  
Cross Sections ◽  
Manufacturing Cost ◽  
Seismic Zone ◽  
Structural Members ◽  
Reinforced Concrete Building ◽  
Reinforced Concrete Slabs ◽  
Concrete Building ◽  
The Cost ◽  
Bearing Structure

Abstract The main scope of the present research is the analysis, dimensioning and estimation of the cost of a five-storey reinforced concrete building, which is similarly constructed in three different seismic hazard zones (ZI, ZII, ZIII). The ground plan of the building is a conventional floor plan with solid reinforced concrete slabs. The cross-sections of the structural members remain stable, except for the columns whose cross-sections are reduced in height. The aim of the present study is to analyze how the cost of manufacturing the load-bearing structure of a reinforced concrete building is affected by the seismic risk of the area, if that influence is significant and in what extent. Moreover, along with the construction cost, the possible influence to the environment is studied, too.

scholarly journals Simplified calculation of flexural strength deterioration of reinforced concrete T-beams exposed to ISO 834 standard fire

2021 ◽  
Vol 15 (4) ◽  
pp. 123-135
Author(s):  
Nguyen Truong Thang ◽  
Nguyen Hai Viet
Keyword(s):  
Reinforced Concrete ◽  
Flexural Strength ◽  
Cross Sections ◽  
Temperature Dependent ◽  
Strength Deterioration ◽  
Standard Fire ◽  
Parametric Studies ◽  
Simplified Calculation ◽  
T Beam

Reinforced concrete (RC) T-shaped cross-section beam (so-called T-beam) is a common structural member in buildings where beams and slabs are monolithically cast together. In this paper, a simplified calculation method based on Russian design standard SP 468.1325800.2019 is introduced to determine the flexural strength of RC T-beams when exposed to ISO 834 standard fire. The idea of 500oC isotherm method, which is stipulated in both Eurocodes (EC2-1.2) and SP 468, is applied associated with specifications of temperature distribution on T-beams’ cross sections and the temperature-dependent mechanical properties of concrete and reinforcing steel. A case study is conducted to explicitly calculate the flexural strength deterioration (FSD) of T-beams compared to that at ambient temperature. A calculation sheet is established for parametric studies, from which the results show that the FSD factor of RC T-beams is adversely proportional to the dimensions of the beam’s web and flange. However, the effect of these components of T-beams is not significant.

scholarly journals THE EFFECT OF HIGH TEMPERATURE ON REINFORCED CONCRETE STRUCTURES

2010 ◽  
Vol 2 (1) ◽  
pp. 12-21 ◽  
Author(s):  
Robertas Zavalis ◽  
Arnoldas Šneideris
Keyword(s):  
Reinforced Concrete ◽  
High Temperature ◽  
Cross Sections ◽  
Concrete Strength ◽  
Temperature Fields ◽  
Concrete Element ◽  
Zone Method ◽  
Standard Fire ◽  
Fire Curve ◽  
Zone Dimension

The article represents the behaviour of reinforced concrete and its components (concrete and reinforcement) under high temperature. The comparing analysis of the experimentally and theoretically obtained results has been performed. The carried out experiment has disclosed that the mechanical properties of concrete alters differently in cases of temperature rise and theoretical reference. The most visible difference has been noticed at a temperature of 100 °C (Fig 4, Fig 5). The main fire resistance calculation basics are discussed. The temperature fields of the reinforced concrete element cross-section are calculated according to the standard fire curve using the program COSMOS/M of the finite element method. Concrete thermal properties, thermal conductivity and specific heat capacity dependence on temperature are taken into account in the model (Fig 10, Fig 11). By means of this model, the corresponding algorithm (Table 2) was made and can be used for obtaining temperature distribution for the reinforced concrete element of different cross-sections. According to the received temperature fields and applying the zone method, the influence of differences in theoretical and experimental results on element load bearing capacity is determined. The residual strength of the element considering the theoretical reduction curve of concrete strength is 5% larger than the results obtained in cases of 30 and 60 minutes heating. 90 and 120 minutes heating indicates that element strength is only 2% larger than the results calculated experimentally. The reduced zone dimension determined due to a decrease in the reduction coefficient at a temperature of 100 °C has affected residual element strength.

scholarly journals PARAMETRIC ANALYSIS ON FIRE RESISTANCE OF ONE WAY SIMPLY SUPPORTED REINFORCED CONCRETE SLABS

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Fidan Salihu ◽  
Meri Cvetkovska
Keyword(s):  
Reinforced Concrete ◽  
Fire Resistance ◽  
Concrete Cover ◽  
Concrete Slabs ◽  
3D Analysis ◽  
Reinforcement Scheme ◽  
Simply Supported ◽  
Standard Fire ◽  
Reinforced Concrete Slabs ◽  
Simplified Procedure

The behavior of simply supported reinforced concrete slabs in fire conditions and the influence ofcertain parameters on their fire resistance is analysed in this paper. The influence of the slab span,concrete cover thickness and the type of reinforcement scheme are analysed. All slabs are exposedto standard fire ISO 834. The analyses are conducted by using the computer program SAFIR2016,which is based on the Finite Element Method, and the simplified procedure given in EN 1992-1-2.For the numerical analyses, two approaches are used: 2D-analysis, when the discretization isperformed with beam elements and 3D-analysis, when the discretization is performed with shellelements. The 3D-analyses are performed for a meter width strip and for the real width of the slabs.The width of the slabs is adopted to be the same with the span.

Fire Resistance of Bar-Reinforced Concrete Filled Steel Columns

2008 ◽  
Vol 400-402 ◽  
pp. 757-762
Author(s):  
Lei Xu ◽  
Yu Bin Liu
Keyword(s):  
Reinforced Concrete ◽  
Theoretical Model ◽  
Numerical Model ◽  
Cross Sections ◽  
Fire Resistance ◽  
Steel Columns ◽  
Mechanic Model ◽  
Resistance Analysis ◽  
Standard Fire ◽  
Good Agreement

In this paper a numerical model for fire resistance analysis of bar-reinforced concrete filled steel columns with square and circular cross-sections have been put forward. The model has been validated by testing results. There is a good agreement. Used of the theoretical model, the relations between the fire resistance and various parameters have been analyzed. On the basis of that, formulas for the calculation of the fire resistance of bar-reinforced concrete filled square and circular steel columns under ISO-834 Standard Fire Curves are developed respectively. The calculated results have a good agreement with those of mechanic model and test.

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