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Transactions of the VŠB - Technical university of OstravaSafety Engineering SeriesVol. VI, No. 2, 2011p. 6 - 10ResultsFire Resistance of the ReinforcedConcrete ColumnThe area of the reinforced concrete column crosssection, A c, is:2Ac 500300 150 000 mm (6)The steel reinforcement area A ais: 2 2Aa 6 20 / 2 3,14 1885 mm (7)The load-carrying capacity of the reinforcedconcrete column under normal conditions N niscalculated as follows:c fcc facNn Ac Aa(8) (9)where:α cload duration factor,γ cpartial safety coefficient of concrete forload-carrying boundary conditions,γ apartial safety coefficient of steel reinforcementfor load-carrying boundary conditions.The load-carrying capacity of the reinforcedconcrete column during fire is calculated as follows:Nr,fi fiNn 0,7 5,07 3,549kN(10)where:η fiN nload level during fire.The Zone Methodc0,8550 500150000 18851, 5 1,155069565,22N 5,07MNThe zone method for calculating fire resistanceof construction elements focuses on the impact offire heat on concrete inside the sections (zones),whereby temperature is determined as its mean valuein the centre of each section (EN 1992-1-2, 2004).Strength reduction factor kc(t) of silica aggregateconcrete is calculated with the following expressions:For 20 ºC ≤ t ≤ 100 ºC kc t 1, 0 (11)105 0,05tFor 100 ºC ≤ t ≤ 200 ºC kc t (12)100230 0,2tFor 200 ºC ≤ t ≤ 400 ºC kc t (13)200540 0,6tFor 400 ºC ≤ t ≤ 800 ºC k (14)ct 400aFor 800 ºC ≤ t ≤ 900 ºC710,07tkc t 100(15)For 900 ºC ≤ t ≤ 1000 ºC44 0,04tkc t 100(16)For 1000 ºC ≤ t ≤ 1100 ºC34 0,03tkc t 100(17)For 1100 ºC ≤ t ≤ 1200 ºC120 0,1tkc t 100(18)The mean value of the strength reduction factork c,mis determined based on the expression:0, 21nkcm,n kctin i1(19)Effective width of a section damaged by tensilestress is determined based on the damaged sectionwidth a z, which, in turn, is calculated with thefollowing expression:1,3 kcm, az1 kctM (20)where:ω half width of sectionk c(t M) strength reduction factor of concrete attemperature t in the center of slice.Calculated fire resistance values for thereinforced concrete columnWe divided the cross section of the reinforcedconcrete column into zones and calculatedtemperatures in the sections of those zones over thedistances x = 30 mm, x = 90 mm, and x = 150 mm.Concrete strength reduction factor in the column’scross section is given in Fig. 4.Fig. 4 Change in concrete strength reduction factorwith temperatureReinforcement 1 is exposed to fire on oneside, whereas reinforcement 2 is exposed to it ontwo sides. Fig. 5 shows temperature values for8