o_19jdnovcg1eh21852116govv1lgra.pdf

EVENT TECHNOLOGY I
Trusses in event technology according to Eurocode
Trusses are used in event technology as load bearing elements for example for stages,
tents and riggs. This use requires the compliance with quality standards in the production
of the trusses and the proof of stability of the construction by a structural analysis.
Meanwhile this has to be done according to
the following European standards:
EN-1999-1-1Eurocode 9:
EN-1090-3:
Design of aluminium structures
Part 1-1: General structural rules
Technical requirements for
aluminium structures
These codes represent the generally accepted standards of
technology. In Germany the lists of acknowledged technical
construction regulations of the federal states as well as the
accident prevention regulations refer to these codes. After a
transitional period the former relevant German standard DIN
4113 part 1 – 3 is obsolete now.
In Germany it is established to proof the compliance with the
standards by a certification of a technical testing association
(by example TÜV) . This certification usually includes a check
of the welding qualification certificate and the published load
charts. Therefore these certifications have also to be updated
according to the new standards. The values in the load charts
of all trusses and manufacturers will change at least slightly.
Note: This certification has no significance for constructions
that need building authority approval. The use has to be
checked for every single case, but in doing so the same
standards are valid.
This article deals with the changes that were made in
Eurocode 9 compared to DIN 4113 and gives background
information on the use and applicability of load charts.
What changed with the implementation of the Eurocodes
resp. what remained the same?
First off:
The quality of the used aluminium alloy and the competence
of the welder have not changed with the introduction of
Eurocode 9. In other words, a truss that has been manufactured
before the implementation of Eurocode 9 has no better
or worse quality than a truss manufactured after the
implementation.
What changed is the basic safety concept (not the safety level)
and the determination of the bearing capacity. This is why the new
load charts can and will differ from the old charts.
Safety concept:
DIN 4113 which is no longer valid, was one of the last standards
based on a safety concept with global safety factors.
According to this concept all safeties that have to be
considered were applied generally on the material side which
means the actual material data, e.g. tensile strength or yield
strength of the aluminium alloy was reduced by a global
safety factor.
All new standards and thus also Eurocode 9 define a safety
concept with partial safety factors. It is differentiated
between uncertainties on the loading side and on the material
side. For the calculation the existing or expected loading, the
so called characteristic loads are increased by a safety factor
and the bearing resistance of the aluminium elements is
reduced by an additional own safety factor. The bearing
capacity according to DIN 4113 is therefore not equivalent to
the bearing capacity according to Eurocode 9. Only if the
safety factors on the loading side are taken into account the
values are comparable.
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