Summaries
The design of the piers
The design of the piers of the storm-surge
barrier has been completed. In March 1979 a
start was made with the construction. The base
of the piers will have oblique sides and vertical
headwalls. There will be no 'skirts'. Depending
on its place on the sill, the pierbase will be 8 to
12 m buried in the sill. The baseplate,
measuring 25 x 50 m, will be subdivided by
bulkheads.
In other parts of the pier minor changes have
also been introduced as a result of
optimalisation studies: the sillbeams will have a
trapezoid shape and will be cast in one piece.
For transport, the pier will be lifted from the
base, because in this way no pre-stressing in
the piershaft will be required. Instead of two
sleeves there will be only one sleeve in the
shaft. The superstructure was simplified
considerably: eventually it will consist of only
one tubular bridge with the lowest side at MSL
8 m.
Set-up of construction-site 'Schaar'
The existing construction-site 'Schaar' in the
middle of the Oosterschelde was chosen as the
place where the piers for the storm-surge
barrier will be constructed 'in the dry'.
Afterwards the construction-site, subdivided
into 4 compartments, will be flooded in
sequence, in order to allow the catamaran to
enter, to lift the piers and to transport them to
theirfinal places in the mouth of the
Oosterschelde.
110 model tests at Kats for the pier construction
To improve the knowledge of the statical and
cyclical loads on the piers of the storm-surge
barrier 1:10 model tests at Kats were made. The
sill construction and the pier were reproduced,
and the wave and current loads were simulated
at scale.
The translation of the pierswas determined more
precisely than was done by previous
calculations. Moreover, the tests made it
possible to refine and to test the calculation
method.
Soil improvement in the alignment of the
storm-surge barrier
Soil layers in the alignment of the barrier which
are not supportive enough will have to be
compacted by vibration, and as far as this is not
economically or technically feasible, they will
have to be dredged away and replaced by sand
containing no silt.
A distinction has been made between soil
improvement up to 3 m below the pierbase and
soil improvements which reach deeper. The
latter improvement needs only to be executed
in the Roompot channel over a considerable
length.
The catamaran
The final design of the catamaran will be
finished in the second half of this year. The ship
will transport the piers as well as place them.
The initial plan to steady the ship on four legs at
the place of destination before lowering the
piers, has been abandoned. The accuracy of the
placing appeared to be sufficient when the
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