Steel Buildings in Europe

Part 7: Model Construction Specification 7 - 13 completion and stability of the structure and its components (see § 4.7(1) of EN 1991-1-6). The contract documents shall specify the maximum allowable wind velocity during crane operations or other short term execution stages (see § 4.7(1) of EN 1991-1-6). The contract documents shall specify, when relevant, accidental design situations due to cranes or exceptional conditions applicable to the structure or its exposure, such as impact, local failure and subsequent progressive collapse, fall of structural or non-structural parts, and abnormal concentrations of building equipment and/or building materials, water accumulation on steel roofs, fire, etc. (see Clauses 4.12(1) and (3) of EN 1991-1-6). The contract documents shall specify, when relevant, the design values of the ground acceleration as well as the importance factor  I to be taken into account for the assessment of seismic actions, given the reference period of the considered transient situation (see § 4.13 of EN 1991-1-6). The contract documents shall specify the characteristic values of horizontal actions due to imperfections or deformations related to horizontal displacements to be taken into account during execution phases (see § A1.3(1) of EN 1991-1-6). 4.6 Accidental actions EN 1991-1-7 describes Principles and Application rules for the assessment of accidental actions on buildings and bridges. The following actions are included:  Impact forces from vehicles, rail traffic, ships and helicopters  Actions due to internal explosions  Actions due to local failure from an unspecified cause. EN 1991-1-7 does not specifically deal with accidental actions caused by external explosions, warfare and terrorist activities, or the residual stability of buildings damaged by seismic action or fire. National choice is allowed through clauses listed in the Foreword to EN 1991-1-7. Additional contract document requirements According to § 2(2)P of EN 1991-1-7, the contract documents may specify the treatment of accidental actions which are not classified as free actions. According to § 3.1(2) of EN 1991-1-7, the contract documents shall specify the strategies and rules to be considered for accidental design situations. According to § 3.1(2) of EN 1991-1-7, notional values for identified accidental actions may be specified in the contract documents.