Eurocode 5 applies to the design of buildings and other civil engineering works in timber (solid timber, sawn, planed or in pole form, glued laminated timber or wood-based structural products) or wood-based panels jointed together with adhesives or mechanical fasteners.
EN 1995 is only concerned with requirements for mechanical resistance, serviceability, durability and fire resistance of timber structures. Other requirements, e.g. concerning thermal or sound insulation, are not considered.
EN 1995 consists of two main parts.
- Part 1-1: General - Common rules and rules for buildings
- Part 1-2: General - Structural fire design
- Part 2: Bridges
National annex for EN 1995
This NA lays down the conditions for the implementation in Denmark of EN 1995-1-1 for construction works in conformity with the Danish Building Act or the building legislation. Other parties can put this NA into effect by referring thereto.
We have collected a list of questions (and answers) in response to inquiries on EN 1995 - Eurocode 5
Punched metal plate fasteners, service class 3
Question: From Table 4.1 on page 30 in EN 1995-1-1 it is stated that punched metal plate fasteners of stainless steel, service class 3, must be used. This may lead you to think that punched metal plate fastener joints can be used in service class 3.
However, repeated and prolonged exposure to wetting and drying in service class 3 (over several years) may result in a release of the punched metal plate fasteners. Apparently, this is the reason why, so far, no punched metal plate fasteners have been proved for use in service class 3. That punched metal plate fasteners are not intended for use in service class 3 can be demonstrated by the fact that the IT program normally used by the producers in the design process cannot handle service class 3. Moreover, the test conditions of EN 1075 do not seem to reflect such long-term effects.
Suggestion 1: A note should be used to make aware of this problem, and, if necessary, punched metal plate fasteners should not be included in column of service class 3 of Table 4.1. In case punched metal plate fasteners are used in service class 3, the conditions for use should be stated in the form of a requirement for the length of the period of use (service life), in order to ensure that the punched metal plate fasteners are not released as a result of exposure to wetting and drying.
In relation to the above, the committee is requested to state their opinion on the use of punched metal plate fasteners for rafters for scaffolding in connection with the casting of concrete bridges. Are there any special requirements to be fulfilled for storage and installation/erection on site? Are there any special design assumptions to take into account? So far, it is assumed that new rafters are applied and not reused rafters.
Answer: The committee agrees that the wording on punched metal plate fasteners in service class 3 should be specified. As it cannot be said to be a mistake, it cannot be corrected until in the next edition of EN 1995-1-1.
Regarding new rafters, the committee sees no risks in using common galvanised punched metal plate fasteners in temporary structures even though they are referred to service class 3, as corrosion will not be a problem in practice, and experience shows that the metal plate fasteners do not come loose during limited pot life.
For long-term projects it is, however, appropriate to provide for a visual inspection every 6 months to determine if the metal plate fasteners have come loose, or if the galvanising has corroded. Any reuse should only take place, if a complete inspection procedure is specified, supplemented by extra attachments of the punched metal plate fasteners, if necessary.
Question: A minimum overlap of punched metal plate fasteners is specified in EN 1995-1-1, Clause 9.2.2 (4). Is that the absolute requirement, so that a position tolerance must be added in the design process?
Answer: The minimum requirement of 40 mm is absolute. Where the requirement for one third of the height of the timber member is decisive, it is not necessary to add tolerances if the splitting capacity can be verified for the actual position.