NOTATIONS

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b material parameter in the walls, width of a steel section, width of a plate c specific heat, width of a plate in an open steel section ca specific heat of steel cp specific heat of protection material d diameter of a circular hollow section deq characteristic size of a structural member df flame thickness dp thickness of a fire protection material f factor for the effect of non-uniform bending moment distribution on lateral torsional buckling fb stress due to bending moment fc stress due to axial force f0.2p,? 0.2% proof strength fp,? limit of proportionality of steel at temperature ? fu ultimate strength at 20 ºC fu,? ultimate strength of steel at temperature ? fy yield strength at 20 ºC fy,? effective yield strength of steel at temperature ? h height of an opening, height of a radiating surface, height of a steel section, height of a component being considered above the bottom of the beam impinging heat flux heat flux at the surface of a steel element heq averaged height of the vertical openings hw depth of the web i radius of gyration of a cross section k multiplication factor in the parametric fire model k2%,? correction factor for the determination of the yield strength of stainless steel at elevated temperature kb,? reduction factor for bolts kp0.2? reduction factor for the 0.2% proof strength kE,? reduction factor for the Young's modulus kE,?,com reduction factor for the Young's modulus at the maximum steel temperature in the compression flange kp,? reduction factor for the limit of proportionality ksh correction factor for the shadow effect ku,? reduction factor for tensile strength of stainless steel at elevated temperature kw effective length factor referring to end warping kw,? reduction factor for welds ky,? reduction factor for the effective yield strength ky,?,com reduction factor for the yield strength of steel at the maximum temperature in the compression flange ky,?,web reduction factor for the yield strength at the web temperature ?web kz effective length factor referring to end rotation on plan k? reduction factor for a strength or deformation property ks plate buckling factor l length of a member lfi buckling length in fire situation p moisture content of a protection material qc heat flux by convection qcr combine heat flux by convection and radiation qEd design value of a distributed load in the normal situation qf,d design value of the fire load density related to the floor area qfi,Ed design value of a distributed load in the fire situation qr heat flux by radiation qt,d design value of the fire load density related to the total area of enclosure r horizontal distance from the fire plume, distance between an emitting an a receiving surface, root fillet t time, thickness of the walls in a hollow section, plate thickness in general t* expanded time in the parametric fire model tf flange thickness tfi,d design value of the fire resistance tfi,req required fire resistance time tlim limit time in the parametric fire model tmax duration of the heating phase in the parametric fire model tv length of the horizontal plateau in a heating curve tw thickness of the web w width of a radiating surface wt sum of the window widths x cartesian coordinate y parameter in a localised fire model, cartesian coordinate z vertical elevation in a fire plume z' vertical position of the virtual heat source zg level of the application of the load zi distance from the plastic neutral axis to the centroid of an elemental area z0 vertical position of the virtual origin of the fire source

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A area of a wall, cross section area of a steel member, surface area of a member exposed to the heat flux Ac gross cross sectional area of a plate Ac,eff effective area of the compression zone of a plate Ad indirect fire actions Am surface area of a member exposed to the heat flux Am/V section factor of unprotected sections Ap/V section factor of protected sections [Am/V]b box value of the section factor Af floor area Afire area of a fire source Ap appropriate area of fire protection material per unit length of a member At total area of an enclosure, including the openings Av area of a vertical opening, shear area C matrix of capacity, compression force C' compression force D the diameter of a fire, depth of a beam D/W ratio for the external members E Young's modulus of steel Ea,? Young's modulus of steel at temperature ? Ed effects of actions in the normal situation Efi,d design effect of actions for the fire situation Efi,d,t design effect of actions for the fire situation at time t EIz flexural stiffness of a section EIw warping stiffness of a section F thermal load vector Fb,Rd design bearing resistance of bolts at normal temperature Fb,t,Rd design bearing resistance of...