Toleranzen und Vorhaltemaß der Betondeckung beim Nachweis der Feuerwiderstandsdauer im Massivbau

Concrete cover tolerances and allowance with regard to the fire resistance design of concrete structures

Regarding the fire resistance design of reinforced and prestressed concrete members the cover of reinforcement is one of the most important parameters. With reference to the chargeable concrete cover, the problem of how to ensure the same standards for new and existing buildings hasn't been solved so far. In contrast to historical buildings the use of the nominal dimension is undoubtedly normatively admitted for new constructions. However, the first-mentioned often require the interpretation of concrete cover measurements.
To guarantee a comparable safety level in future in case of fire between new and existing structures, this article deals with the realization and probabilistic assessment of the named measurements. Specific attention is given to the unavoidable statistical scattering and its effects on the fire safety of various structural member types. Practical examples visualize the treated subject. Based on the results gained from these investigations, a new approach is established to define the chargeable cover of reinforcement for the fire resistance design.