Sekundarni jezik: |
Angleški jezik |
Sekundarni naslov: |
Fire analysis of two-layered composite planar structures |
Sekundarni povzetek: |
Subject of the dissertation is a new numerical model for geometrical and material non–linear fire analysis of steel–concrete two–layered composite beams accounting for longitudinal and transversal partial interlayer interaction. The numerical procedure consists of three mathematically uncoupled phases. For the determination of the time–dependent development of temperatures in the fire compartment standard fire curves are used in the first phase. In the following hygro–thermal phase, coupled heat and moisture transfer in the analysed beam is determined. For the steel layer of the beam Fourier law of heat conduction is employed. In the reinforced concrete layer, the distributions of temperatures, pore pressures, and free water contents are defined by a system of mass and energy conservation equations and considering phenomena such as phase transitions (water evaporation and water vapour condensation), release of chemically bound water, capillary pressure and difussion of adsorbed water. For structures endangered by the concrete spalling phenomenon, the stress-strain state in the beam at room temperature is accounted for in the calculations of the time–dependent permeability of the concrete. The final mechanical part of the fire analysis deals with the time–dependent stress–strain state of the composite beam. The most important novelties of this part of the model are: (i) each of the layers of the composite beam is modelled separately by the kinematically exact planar beam theory of Reissner and the contact constitutive law is described in dependence on the longitudinal and the transversal slips between the layers and on the uplift; (ii) contact constitutive laws are described in an average base established from tangential and normal contact basis vectors; (iii) material non–linear and temperature–dependent behaviour of steel and concrete layers is described using the principle of additivity of strains where viscous creep of steel and creep and transient deformations of concrete are explicitly considered. In the zones of cyclic loading and reloading of the structure, hardening of the material is accounted for by the model of kinematic hardening. In the second part of the dissertation the new proposed model is validated against experimental data and the proposed numerical procedure is proven to be adequate and accurate for the fire analysis of stiffness, ductility, and bearing capacity of an arbitrary beam of this kind. All of the calculations of this as well as of the final part of the dissertation are performed using the computer softwares MoistureHeat2 and
CompositeBeam both computed in the computing environment Matlab. An important finding of the verification chapter of the thesis shows that the impacts of the mechanical loading of the beam and the
effects of restrained thermal dilatations are to be considered in the hygro-thermal part of the analysis if
not only temperature but also pore pressure development is important (i.e. in an analysis |
Sekundarne ključne besede: |
Built Environment;civil engineering;doctoral thesis;fire analysis;composite beam;slip;uplift;heat transfer;moisture transfer; |
URN: |
URN:NBN:SI |
Vrsta datoteke: |
application/pdf |
Vrsta dela (COBISS): |
Doktorsko delo/naloga |
Komentar na gradivo: |
Univ. v Ljubljani, Fak. za gradbeništvo in geodezijo, Doktorski študijski program Grajeno okolje, smer gradbeništvo |
Strani: |
XXVIII, 113 str. |
Vrsta dela (ePrints): |
thesis |
Naslov (ePrints): |
Požarna analiza dvoslojnih kompozitnih linijskih konstrukcij |
Ključne besede (ePrints): |
gradbeništvo;disertacije;kompozitni nosilec;požarna analiza;zdrs;razmik;prenos toplote;prenos vlage; |
Ključne besede (ePrints, sekundarni jezik): |
civil engineering;thesys;fire analysis;composite beam;slip;uplift;heat transfer;moisture transfer; |
Ključne besede (ePrints, sekundarni jezik): |
civil engineering;thesys;fire analysis;composite beam;slip;uplift;heat transfer;moisture transfer; |
ID: |
8312750 |