onstruction of purposebuilt Equipment',
lust rates how the design of the special-purpose
quipment for the Oosterschelde barrier
eveloped simultaneously with the design of
he storm-surge barrier itself. Some working
essels, such as the 'Macoma' and 'Ostrea' are
ompletely new designs whereas others, such
s the 'Taklift IV' are only bigger copies of a
nown design. In other cases, existing
quipment was adapted or modified for new
jnctions. The newly developed equipment is
o unique that most of the costs involved will
ave to be written off against this project. The
quipment was designed in collaboration with
ne Contractors Combination 'Dosbouw' who,
n behalf of Rijkswaterstaat arranged tendering
nd putting out to contract. The purely technical
de of shipbuilding, and this applied to all the
essels, was surpassed in importance by the
echnical engineering, by the electrical
stallations and by advanced measuring
istruments which had to be supplied by
ub-contractors. Therefore, the organisational
de of building these ships was primarily the
nost difficult task.
he vessels, and all the activities that they
vould have to perform in the closure gaps,
ere subjected to a wide range of preliminary
tsts. During these tests not only the
esign-requirements were taken into account
ut also the systematically analysed risks. For
he process-analyses, the subsidiary processes
ere subdivided into 'functional interrelations',
hese procedures are discussed in the chapter
ests performed with working vessels'.
he next chapter describes the 'Measuring
ctivities'. For many years, measurements
ave been taken to determine the hydraulic
rms of reference for the Oosterschelde
arrier. For this purpose a dense measuring
id was set out in the mouth of the
osterschelde. For the construction of the
ers, and for the exact position-finding during
e execution of the works in the closure gaps,
system of coordinates and contours was laid
it. Various position-finding systems were
stalled. The bed topography was also
jistered. All the large vessels were equipped
h precision measuring systems which
nsisted of self-acting theodolites, acoustic
paratus and wire measuring systems. Bij
draulic standards, extremely accurate
armation is now being gathered. Sonar
-hniques are being used for submarine
rasurements, although it must be conceded
the contribution of human divers is
spensable.
The 'Forecasting systems' require special
attention. The conditions in which the very
sensitive operations for positioning can take
place in the mouth of the Oosterschelde are
limited. In collaboration with the Royal
Netherlands Meteorological Institute, a special
agency has been instituted for this purpose. It
forecasts the weather and working conditions
exclusively for the Oosterschelde estuary.
These forecasts are published regularly three
times every 24 hours via hydro-meteo-bulletins
and on request, additional information can be
furnished. Coordination between the work-force
and the forecasters has been entrusted to the
Executive Office Storm-surge Barrier
(Uitvoeringspost Stormvloedkering) on the
Neeltje Jans Construction Island.
The 'Technical implementation' of the works in
the mouth of the Oosterschelde requires a
complex organisation within which various
project groups can operate with a reasonable
degree of independence with the assistance of
staff groups and overall coordination by the
project management. The special manner in
which the barrier has to be built requires an
exeptional type of contract i.e.a 'frame contract'.
In this contract, the principal and contractor
have committed themselves to a long-term
collaboration in accordance with previously
agreed rules. The subsidiary contracts will be
specified at a later stage. Some items, such as
the acquisition of materials, have been excluded
from the contract so as to enable a better
reaction to the prevailing market conditions.
This chapter also discusses the decision-making
process under difficult organisational
circumstances.
'Control of the cost and planning' are two
crucial aspects of the management behind the
building of the Oosterschelde barrier. These
were made even more difficult as the financial
terms were laid down in 1976 at which time
only a rough outline of the design existed. The
various project groups are obliged to perform
their specified tasks under strict budgetary
limits, within which financial setbacks must be
absorbed as best as possible. A stream of
information and reports keeps the higher
management levels posted on all aspects and
variations in expenditure and planning.
In the 'Epilogue' of this special edition the
Oosterschelde Project is related to the social
changes which have occurred in recent years. It
also briefly describes the interrelation between
time, money and quality in projects such as
this undertaking.
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