Steel Buildings in Europe

Title Worked Example – Fire safety strategies and design approach of steel floor beam 9 of 10 6 - 57 For illustration purposes, the IPE300 S275 beam used in this example is used as a composite beam, with the following assumptions for use in Fracof:  IPE550 S275 primary beams  Cofrastra 40 deck  130 mm deep slab, using C25/30 concrete  ST 40 C mesh, 500 N/mm 2  All beams assumed to have 100% shear connection. The design value of the actions for normal temperature is 9,23 kN/m 2 . The reduction factor for fire has been calculated as 0,477, which gives a fire action of 4,4 kN/m 2 . For these input details, Fracof determines that it is adequate to use unprotected IPE300 secondary beams for R60 fire resistance. The details are summarised in the table below and graphically shown in the figure below. According to the data shown in the table, after 20 minutes fire exposure, the beam capacity is 3,36 kN/m 2 < 4,4 kN/m 2 fire action. Considering the slap capacity, the total resistance remains over 9 kN/m 2 after 60 minutes fire exposure, which means that the beam doesn not need to be protected.