EN 1990 Appendix D (Design assisted by testing): Conversion Factor value

Copy and paste of some relevant clauses ;

Section 1 General
1.1 Scope
(1) EN 1990 establishes Principles and requirements for the safety, serviceability and durability of structures, describes the basis for their design and verification and gives guidelines for related aspects of structural reliability.

(2) EN 1990 is intended to be used in conjunction with EN 1991 to EN 1999 for the structural design of buildings and civil engineering works, including geotechnical aspects,structural fire design, situations involving earthquakes, execution and temporary structures.

D1 Scope and field of application
(1) This annex provides guidance on 3.4, 4.2 and 5.2.

(2) This annex is not intended to replace acceptance rules given in harmonised European product specifications, other product specifications or execution standards.


ηd = Design value of the possible conversion factor (so far as is not included in partial factor for resistance γM) and ηd is 0.85 for concrete and 1.0 for steel .

Although it is not explicitly stated , EN 1990 should not be used for bolted and threaded connections. I will suggest you to look Clause 3.6 of BS EN 1993-1-8. The design of a bolted and threaded connections are semi-empirical, based on past experience ,performance, practice and validated with a statistical evaluation of test results. An example of a semi-empirical rule is given in Clause 3.6.1.

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