Dynamic Behaviour of Structures
Introduction
The development of materials with a higher strength - including both
development of the classical materials, steel and concrete, and development of
new materials - opens up opportunities that have not yet been accessible:
Construction of structures with longer spans and of structures with elegant and
slender forms. A characteristic feature of this development is, that an increase
in the strength of material does not lead to a corresponding improvement of the
stiffness of the material.
Therefore the design and analysis of structures that utilize the opportunities
of the new materials, must to a much higher extent focus on those phenomena that
depends on the stiffness including the flexibility, stability and dynamic
behaviour of the structures.
The dynamic behaviour of structures is important in relation to safety and may
also be decisive for the comfort of the persons who use the structures.
ES-Consult has worked with projects and research- and development works, where
this problem has been in focus. The company has at it's disposal a digital
tri-axial accelerometer allowing accurate and easily obtained measurements of
vibrations in structures of any kind.
Special Assignments
In connection with the assessment of a typical modern deck in house building
ES-Consult has analysed the dynamic characteristics of the structure during
typical use (with persons walking, running etc.). Analyses of this kind are
necessary in order to prevent the structures causing discomfort to the users.
During the design of the road link across the Great Belt, ES-Consult has
carried out a follow-up of the performed wind tunnel tests for the building
owner. The bridge structure - a road-carrying suspension bridge with a main span
of 1624 m and with relatively slender approach spans - had such proportions,
that a more careful investigation concerning the aeroelastic characteristics of
the bridge and its behaviour was necessary. The span length of the approach
spans was increased by using high strength steel. Thereby the dynamic behaviour
of the structure became an important feature, and calculations supported by
tests performed by The Danish Maritime Institute resulted in the use of tuned
mass dampers in order to eliminate vibrations caused by vortex shedding.
The Øresund Link will be built as a combined railway-road link. It is required
that trains shall be able to pass over the bridge with a speed of up to 200
km/h. In relation to this ES-Consult has carried out a structural dynamic
analysis and a comfort analysis for the building owner. Both analyses describe
the dynamic interaction between the train and the bridge.
The comfort aspect of dynamic behaviour of structures has been an element in
several of the investigations carried out.
Litterature
A list of papers produced by the staff members is available.
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