e-mosty December 2018 e-mosty December 2018 | Page 13

Figures 9 - 11: Tower Details
Thin sheet steel is cut to the developed shape of the
geometry and controlled by the use of steel
diaphragm stiffeners, a similar process employed in
the shipbuilding industry.
Another innovative structural element occurs in the
cable stay design where steel saddles are housed
within the tower and allow for the load transfer of the
stay cables to occur in a natural compressive state
applied radial to the axis of the saddle and virtually
along the axis of the tower.
This arrangement offers several benefits over the use
of traditional tower cable anchors. Importantly, it
allows for a slender tower with sculpted surfaces as
less mass is required to resist the forces found in the
stays of a conventional cable stay design.
It also allows flexibility in the range of tower shapes,
and is cheaper to build and maintain.
6. QUALITY CONTROL AND FINISHES
The finishes to any concrete structural element of the
bridge are a trademark of a designer and have always
played a significant part in my personal design
process. I considered finishes at concept stage as
integral to the overall harmony of the finished
product.
Similarly the detail of the finishes to retaining walls,
abutments, facings and ancillary elements play an
important role in determining the total quality of the
project. A textured finish to exposed inclined concrete
surfaces will not only allow uniform weathering and
reduce streaking but will also enhance and maintain
its long term appearance.
I use a juxtaposition of plain and textured surfaces
using high quality tactile finishes moreover to
contribute to the vibrancy of the completed structure
and engage all of its users. The aesthetics of dividing
what would otherwise be a large plain surface by
texture is well known and I extend this to express the
form of the structural element.
The final quality of finish could not be achieved of
course without good workmanship and quality control
at all stages. This requires the designer to be in
control of the project throughout its construction and
to approve the results of trial segments, which must
form part of the specification, irrespective of whether
they are pier, tower, deck or parapet segments. For
this bridge, and most of my others I personally
inspected all test panels as a control of quality but
also to impress on the construction team the
importance of this facet of the works.
Figure 12: Construction of the bridge showing scale and form of the tower.
Integral deck and tower allows safe construction and a stable platform to mount cranes.
4/2018