In addition to conforming to the requirements of EN 1993-1 (2005, EC3), EC8 incorporates specific rules dealing with the use of a realistic value of material strength in dissipative zones. In this respect, according to Section 6.2 of EN 1998-1, the design should conform to one of the following conditions:
The actual maximum yield strength f of the steel of the dissipative
zones satisfies the relationship: f < 1.1 g f, where f is the nominal
1 1 y,max 'ov 1 y 1 y yield strength and the recommended value of g is 1.25.
he design of the structure is ade on the basis of a single grade and nominal yield strength 'fy' for the steels both in dissipative and non-dissipative zones, with an upper limit 'f ' specified for steel in
dissipative zones, which is below the nominal value fy specified for non-dissipative zones and connections. • The actual yield strength ifyaJ of the steel of each dissipative zone is determined from measurements and the overstrength factor is assessed for each dissipative zone as g = f If.
In addition to the above, steel sections, welds and bolts should satisfy other requirements in dissipative zones. In bolted connections, high strength bolts (8.8 and 10.9) should be used in order to comply with the requirements of capacity design.
In terms of detailed design and construction requirements, in addition to the rules of EN 1993-1, several specific provisions are given in Section 6.11 of EN 1998-1. The details of connections, sizes and qualities of bolts and welds as well as the steel grades of the members and the maximum permissible yield strength f in dissipative zones should be indicated on
the fabrication and construction drawings.
Checks should be carried out to ensure that the specified maximum yield strength of steel is not exceeded by more than 10 per cent. It should also be ensured that the distribution of yield strength throughout the structure does not substantially differ from that assumed in design. If any of these conditions are not satisfied, ne analysis of the structure and its details should be carried out to demonstrate compliance with the code.
Was this article helpful?