Modelling Thermal Insulation Effect of the Interface between Steel Deck and Concrete Slab in Composite Slab Systems in Fire Conditions

Vaddamani, Varun Teja and Agarwal, Anil (2017) Modelling Thermal Insulation Effect of the Interface between Steel Deck and Concrete Slab in Composite Slab Systems in Fire Conditions. Masters thesis, Indian institute of technology Hyderabad.

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Abstract

Steel-concrete composite slabs are gaining importance, due to the ease of construction without heavy lifting machinery and also the performance of steel decking as a permanent formwork and external reinforcement. At elevated temperatures, steelconcrete composite slabs experience debonding of steel deck from the concrete slab. This debonding creates a layer of air which offers thermal resistance to the rise of temperature in the concrete slab. There is very limited numerical or analytical work in the literature that provides a rational framework for thermal resistance offered by this intermediate layer. Experiment data to support the modelling research is also very sparse. As a consequence of de-bonding of steel deck from the concrete slab, the heat transfer from the steel deck to the concrete slab is through radiation and conduction of the intermediate air layer. Preliminary structural analyses of the composite floor systems reported in the literature showed that a proper temperature calculation of the steel deck as well as concrete slabs is of great importance for the thermal gradient of the slab and thus for global load redistribution. The temperatures have a simultaneous effect on mechanical behaviour; and also the mechanical behaviour has a direct effect on temperatures, which can be understood through a fully coupled thermal-stress analysis. ABAQUS software is used for performing numerical simulations. However, there are certain limitations while defining the parameters of radiation. The present work addresses a way to include the radiation effect due to debonding of steel deck in steel concrete composite slab, under standard fire conditions. The factors influencing the radiative heat transfer are studied in detail. As a first step, an uncoupled heat transfer analysis has been performed over a section of steel-concrete composite slab taking into account the radiation and conduction properties using interface elements. The radiation properties are accounted for, using equivalent conductance for the interface elements as a function of temperature. The concrete slab, the interface element and the steel deck are modelled using DC2D4 elements. Material properties for steel and concrete are adopted from Eurocode.

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IITH Creators:
IITH CreatorsORCiD
Agarwal, AnilUNSPECIFIED
Item Type: Thesis (Masters)
Subjects: Civil Engineering
Divisions: Department of Civil Engineering
Depositing User: Team Library
Date Deposited: 05 Jul 2019 11:58
Last Modified: 05 Jul 2019 11:58
URI: http://raiith.iith.ac.in/id/eprint/5638
Publisher URL:
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