The aim of the design was for simplicity, rationality
and straightforwardness: to express function and
structure in a direct way without unnecessary detail.
Well-proven design concepts, materials and
construction methods were used to create a strong
and robust form that would stand in an open
seascape with only the sky and the sea as the
backdrop.
Unlike the straight alignment of the reference scheme
for the competition an S-curve was introduced in the
horizontal alignment to give travellers unique views
from the bridge of an ever changing sky and sea with
a play of light reflecting shades of grey and blue, and
views of the gently curved coastlines and Saltholm
island, Figure 10.
Figure 11: Approach span at 140m gives lighter
and elegant appearance
The rigid look and the flow of forces in a cable stay
bridge are not readily understood, but at Oresund
the cable stay bridge is part of the long approaches
and the truss allows it to join readily with the trusses
of the approach bridges, resulting in a continuous
girder of uniform and consistent design tying the
whole bridge length together, Figure 12.
Figure 10: Horizontal S-curve of the bridge
However the alignment was altered to a C-curve to
simplify the alignment at Copenhagen Airport and
improve water flow through the Link, Figure 8.
For a two level bridge, the most economical structure
is steel truss with diagonals connecting the upper and
lower decks. The deep girders naturally led to longer
approach spans of 140m, which has environmental
advantages of achieving the specified obstruction of
less than 1% for water flowing in and out of the Baltic
Sea. It also gives a lighter and more elegant
appearance, Figure 11.
The navigation channel bridge is a cable stay bridge
with a steel truss deck which helps to neatly give the
necessary rigidity for a railway bridge.
1/2018
Figure 12: Elevation of cable stayed spans
showing continuity of truss into approaches
The stiffness of the truss deck was the driving factor in
choosing the harp pattern for the stay cables. The
repeating geometry of the truss has a natural affinity
with the harp, which was highlighted by matching the
inclination of truss diagonals and the stay cables,
Figure 12.
The cables are arranged in vertical planes, with the
cables symmetrical about the towers, Figure 13.