7. Design calculation rules

For a long time, the CB71 rules were the only calculation methods applicable to the design of timber structures, in order to provide a degree of safety appropriate to their purpose and duration. In simple terms, these rules defined an overall safety coefficient.

Since 2005, Eurocode 5 (or NF EN 1995) is in theory the only applicable normative document for the design and dimensioning of timber structures [C 2 242] . It describes the principles and requirements for the safety, serviceability and durability of timber structures. This standard incorporates the recent concept of ultimate limit states and serviceability limit states, as well as partial coefficient methods.

It is the use of these partial safety coefficients applied to materials and actions on the...