Steel Buildings in Europe

Part 7: Fire Engineering 7 - 31 For the calculation of the design value of the moment resistance, the cross- section of the beam is divided into various components, namely:  the flanges of the steel profile  the web (lower and upper parts) of the steel profile  the reinforcing bars  the encased concrete. To each of these parts of the cross-section, simple rules are given which define the effect of temperatures and allow calculation of the reduced characteristic strength in function of the standard fire resistance R30, R60, R90 or R120. Detailed information is given in EN 1994-1-2 §4.3.4. 5.4 Specific design rules for single-storey buildings National fire regulations of many European countries have been changed recently to introduce, for single-storey storage and industrial buildings with significant fire risks (high fire loads), specific safety requirements in terms of structural behaviour as an alternative to standard prescriptive requirements. The following criteria relating to the structural behaviour of storage and industrial buildings (load-bearing structure, façade elements, roofing and fire walls) must be satisfied to ensure adequate life safety for building occupants and firemen:  In case of fire occurring in one of the cells of the building, its structure (including façade elements) must not collapse towards the outside.  In case of fire occurring in one of the cells of the building, the localized failure of the cell in fire must not lead to the collapse of the neighbouring cells. To help the design of storage and industrial buildings with a steel structure, several simple design methods can be used 5,6 . These design methods allow the designer to easily prove that the behaviour of the steel structure of these buildings in fire situations fulfils the above criteria. The methods are implemented in the LUCA software [15] . The design methods enable the designer to:  Evaluate forces induced by the collapse of the heated part of the structure. These forces should be used as additional horizontal load for the stability check of the part of the frame that remains cold during the fire. That part can be assessed using normal conditions design tools for structure analysis.  Provide maximum horizontal displacements developed at the ends of the compartment affected by the fire. These displacements are used to ensure that movements of the structure in the event of fire do not adversely affect the stability of fire walls or building façades. Design methods used for this verification depend on the type of the wall (such as in lightweight concrete, reinforced concrete, hollow block, steel sheeting with insulator, plasterboard, bricks, etc.) and connection to the steel frame.