Steel Buildings in Europe

Part 4: Detailed Design 4 – 47 6 ROBUSTNESS 6.1 Accidental design situations In order to avoid the disproportionate collapse of buildings in the case of accidental situations, such as explosions, Section 2.1 of EN 1990 states two Principles and provides one Application Rule for the robustness of structures. These are as follows: (4)P A structure shall be designed and executed in such a way that it will not be damaged by events such as:  Explosion,  Impact, and  the consequences of human errors, to an extent disproportionate to the original cause. NOTE 1. The events to be taken into account are “those agreed for an individual project with the client and the relevant authority”. NOTE 2: Further information is given in EN 1991-1-7. (5)P Potential damage shall be avoided or limited by appropriate choice of one or more of the following: – avoiding, eliminating or reducing the hazards to which the structure can be subjected;. – selecting a structural form which has low sensitivity to the hazards considered; – selecting a structural form and design that can survive adequately the accidental removal or an individual member or a limited part of the structure, or the occurrence of acceptable localised damage; – avoiding as far as possible structural systems that can collapse without warning; – tying the structural members together. (6) The basic requirements should be met: – by the choice of suitable materials. – by appropriate design and detailing, and – by specifying control procedures for design, production, execution and use relevant to the particular project. The strategy to be adopted with both identified and unidentified accidental actions is illustrated in Figure 6.1 and depends on three consequence classes that are set out in EN 1991-1-7 [13] Appendix B.3 and discussed in Section 6.2.