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Sanierung Große Seeschleuse in Emden - Vortrag von Prof. Dr. Clasmeier auf englisch und deutsch - PIANC MMX Congress Liverpool UK 2010
23.12.2010 [PDF Export]    Zurück zur Liste
Erich Bolinius

Unten auf Deutsch  - ohne Fotos und Schaubilder -

PIANC MMX Congress Liverpool UK 2010
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Feasibility Study for Renewing the “Large Sea-Lock” in Emden
by
H.-D. Clasmeier1
ABSTRACT
The Port of Emden is the most western German port at the North-Sea-coast. It is located beside the
Dutch - German Border in the Ems – Estuary called the Dollard Bay. One part of the harbour (200 ha)
is under tidal influence, the other part (530 ha) is situated at an impounded dock. The Outer Harbour is
used mainly for handling vehicles in export and import, the Inner Harbour is important for the
production and handling of wind power aggregates and also for two ship yards. In 2008 the total
number of goods handled in the port was more than 7.0 Mio. tons.
The development of the modern Emden Port has started in 1882 with the operation of the Nesserland
Sea-Lock (W = 14.00 m; L = 110.00 m). In 1913 the Large Sea-Lock (W = 40.00 m; L = 260.00 m) has
gone into operation as the more important access to the dock of the Inner Harbour. Due to both locks
the Port of Emden became very busy for ore import for the German steel-works in the Ruhr District
and for the coal export from there. In 1975 the total throughput of goods had reached its maximum
with more than 16 Mio. tons.
Port of Emden; Layout of new Sea-Lock above left
The increasing bulk-carrier dimensions in the 70th of the last century let grew the plan to build a new
impounded harbour in the estuary, the “Dollard-Dock-Project” and make it accessible for vessels up to
150.000 dwt. The Nesserland Lock and also the Large Sea-Lock should have been removed and the
old Inner Harbour would have become as a part of the new Dollard-Dock. To realize this plan it was
foreseen to start the works in 1991 and taking a new large sea-lock in operation latest in the years
1997/98.
1 Technical Director, Niedersachsen-Ports, Emden, Germany hclasmeier@nports.de
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In the year 1980 it was already remarked, that the Large Sea-Lock will have to stay in operation until
1997. The condition of the lock structure was not satisfactory, to guarantee an operation without any
disturbance for more than twenty years. Several investigations to get more information about the
masonry, the concrete, the surrounding soil, the roller gates, the valves and the inlets were made. A
simple renovation concept was realized in the years 1993 to 1997. New gates have been built. The
goal of this concept was to make sure a lock operation for the next 25 years
But in the meantime the Dollard-Dock-Project was cancelled. The Port of Emden today is still within in
its old border. A plan for renewing the old Large Sea-Lock in the existing axis without considerable
disturbing the harbour traffic is needed. The renewed lock should go into operation latest in 2025, so
the time has come to make a feasibility study, how to manage this challenge. Today some 2,500 seagoing
vessels, another 7,500 inland vessels and service boats and over 3,500 pleasure boats have to
be locked in- and out-going the Port of Emden. Because the Nesserland Sea-Lock is out of operation
since 2006, all traffic has to use the Large Sea-Lock. The renovation of the Nesserland Lock has
already started and will be finished in the end of 2012.
The result of the feasibility study must be given to the decision makers in late 2010. So it may be
possible to start in 2018 with the construction works. The first idea is to build new lock heads as
prefabricated concrete caissons and set them outside the lock-chamber directly in front of the old
heads. The gravity wall construction of the lock chamber should be cut by a trench or diaphragm cutter
and a new prefabricated wall element will be setup inside the trench. Some anchors and piles are
required to fix the head of the new chamber wall. The new gate chambers should be able to use them
as dry docks to maintain the gates inside.
New Lock-Chamber with Cruise-Vessel AidaLuna
Due to the old geometrical conditions the new lock will measure nearly 320 m in length and 55 m in
width. Lock gates as bridges or bascule bridges could cross the lock for road traffic. The investment
into a new lock will be 300 – 350 million €.
The paper deals with the condition of the old sea-lock and the current status of planning in December
2009. The oral presentation will give details of the lock construction proposal.
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1. INTRODUCTION
1.1 The Port of Emden
The Port of Emden is situated in the southern German Bight nearby the Dutch border in the Ems-
Dollard-Estuary (Fig. 1). The landscape is characterized by the wadden-sea and low flatlands, partially
below the mean seawater-level. This region with several small fishing harbours and its main port of
Emden is called East Frisia.
Figure 1: Introduction to the Port of Emden
The port area is more than 2,000 ha wide, with more than 20 km of quay walls, piers and
embankments and nearly 40 berths for vessels up to 50,000 dwt. There are also two sea-locks,
movable bridges and some gates in the sea-dike. The Port of Emden is worldwide well-known as the
distribution hub for cars, manufactured by the German Volkswagen Company. In 2007, the annual port
throughput has reached 1,100,000 cars (Fig. 2).
0,00
1,00
2,00
3,00
4,00
5,00
6,00
7,00
8,00
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Inland Vessel traffic
Vehicles
Not specified
Steel products
Container
Building material
Forest products
marble slurry
Grain
Oil and derivates
Island traffic
ore and coal
Figure 2: Port of Emden, ports throughput in the years 1991 to 2009
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Other important goods being handled in the port of Emden are forest products (1,000,000 tons),
liquefied marble (1,000,000 tons), some hundred thousand tons of magnesium brine and liquid
nitrogen fertilizer and more than 200,000 m³ of wind energy parts, like towers, propellers and
generators (Fig. 3). The Nordseewerke shipyard and offshore construction is another important
customer of Emden Port.
Due to the worldwide breakdown of transport volume the total throughput in Emden also decreased of
more than 20 % in the year 2009. But the increasing export of wind power aggregates with its
sophisticated storage and handling was a little compensation.
Today a master plan for the development of the Port of Emden is being devised. It is foreseen to
create some 1,500 ha of new port area in the western part of Emden, connected with the old harbour.
The new port facilities will be situated directly at the banks of the Ems River outside the existing dikeline.
Realizing this master plan will take fifteen to twenty years, but it will strengthen the whole East-
Frisian region in economical point of view (CLASMEIER, H.D. 2008).
Figure 3: Port of Emden, Autoport (left); handling of wind power propellers (right)
1.2 The History of the Large Sea-Lock
Due to dramatic increase of siltation in the old Emden Fairway, the Emden citizens have decided in
1840 to grab a new canal between the Dollard and the Port of Emden. To close this canal at sea-side
with a gate in 1845 was the birth of the Nesserland Sea-Lock and the modern Port of Emden.
Increasing vessel dimensions, as well as the busy harbour activities have demanded in the early 20th
century a larger one sea-lock. In 1907 the port administration has started to build under orders of the
German emperor Wilhelm 2nd the (today so called) “Large Sea-Lock” (ZANDER, W. 1914). With its
dimensions of 260 m in length and 40 m in width it is possible to lock among vessels up to a capacity
of nearly 50,000 tons (Fig. 4).
Figure 4: Construction of the Large Sea-Lock; lock chamber (left); longitudinal culvert (right)
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The sea-lock was at its birth one of the biggest worldwide. It is equipped with one roller gate in each of
the two lock-heads. The lock is in operation every day, so it is not astonished that due to the abrasion
on the roller tracks the port engineers have tried to weld on some material in the 50th at the underwater
rails. Finally the rails were renewed between the years 1985 and 1997 (CLASMEIER, H.D. 1985;
HÜBNER, H.J. 1993).In the years around 1985 it was foreseen to build a new sea-lock at Knock –
landmark and to remove the old sea-lock for a better entrance to Emden – harbour (CLASMEIER, H.
D. et al. 1986). Because the amount to be invested into the so called Dollard-Dock-Harbour project
was more than 1.4 billions DM (today more than 1.0 billions Euros) it was cancelled in 1991. Therefore
the Port Authority has to maintain and to operate the old lock for the next 30 years and to build a new
one later.
Today the “Large Sea-Lock” has become more and more importance, because the second sea-lock,
called the “Nesserland Sea-Lock” is out of operation since late 2006. Currently a new small lock is
under construction and will be realized until 2012. This means, that the live cycle of the Large Sea-
Lock must be limited as least to 2025. About 12,000 vessels need to be locked in more than 6.500
locking operations each year. The Large Sea-Lock will reach the end of its technical life expectancy.
Figure 5: 3-D Model of the old Large Sea-Lock at Emden
The Large Sea-Lock was built in a huge building pit surrounded by dikes to protect it against high
storm surge water levels. So it was possible to react to the different depth of the foundation level. All
parts of the lock (gate and lock chamber) are founded as gravity walls like Fig. 5 it shows.
2. MAIN TOPICS FOR RENEWING THE LOCK
2.1 General Layout
Our forefathers have made the right choice to find the best axis of a sea-lock to navigate safety from
the Ems-River with its dangerous currents into the still water of the Emden Outer Harbour. Today it is
not possible to change this axis because this means to change the fairway in the Ems-River in Dollard
Bay direction into the very sensible and by nature conservation protected Geiserücken2. Due to this
challenge also not possible is to lengthen the seaside access harbour. So it is necessary to look for
2 Geiserücken is the name of a wadden flat in the Dollard area of more than 1,000 ha.
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special elements to improve the approach of large vessels for a safer guidance by using high effective
fender systems.
The natural fairway-depth of the Ems-River at Emden approach is nearly 6 m below chart-datum.
Today it is 8.20 m and it is foreseen to deepen the fairway to 9.20 m. A fairway depth of 9.70 m below
C.D. may be possible. In consequence of this, the depth of a new sea-lock should be also at 9.70 m.
Figure 6: General layout of the old Large Sea-Lock at Emden
Vessels with a draught of more than 12.00 m can arrive at high tide and require a special terminal
directly at the river banks with deeper berths than the river bottom. So it may be possible to keep the
existing structure of the locks “floor” at the depth of 9.96 m below chart datum. The locks floor is
protected with a layer of 40/50 cm high basalt blocks against erosion. The width of the sea-lock is
40.00 m between the lock-headwalls and 43.20 m in the lock-chamber (Fig. 6). Due to side canals
around the lock-head and culverts in the chamber-wall the lock chamber can be filled or emptied (Fig.
5). Renewing the chamber walls in a line behind the existing would give a new width of more than 68
m. It’s too large for the allocation vessel of 50,000 dwt. Another option is, and this is being
recommended, to cut the old masonry in a manner, that the function of the longitudinal culvert will not
be disturbed during the construction phases. These would bring a new width of about 55 m.
The new lock-heads must be positioned in front of the old one. Otherwise a lock operation is not
possible while the new one is being under construction. The suitable length of the lock between the
gates will increase to 320 m. The question whether it is better to build a lock head with double gates
(with the dyke-line in the outer head) or single gates with a second dyke-line around the lock can not
be answered finally at this point.
The “Large-Sea Lock” is the connection between the Inner and the Outer Harbour. Today the lock
gates are open for crossing by vehicles up to a width of 2.00 m and a weight up to 7.5 tons. The
increasing importance for crossing the gates by heavy loaded vehicles up to 60 tons demands a
special gate construction or a movable bridge, irrespective from the gate. In this paper will be
described the gate crossing solution.
In the early years of the last century it was unusual to make some very good documentation, however
our old colleague ZANDER (1914) has done it. So today we are very glad to have excellent series of
photos, descriptions and drawings to reconstruct almost every section of the site history, like it is given
in the 3D animation.
2.2 Planning due to the Means of Port Operation
A number of more than 15,000 vessels, starting with the small pleasure and sailing-boat, going to a lot
of inland vessels up to the sea-going car- and bulk-carrier with a length of more than 220 m require a
lock-passage to arrive and to leave the inner port of Emden each year. The Large Sea-Lock normally
is used to lock the bigger vessel and some inland and coastal going ships. The smaller ones normally
are requested to use the Nesserland Lock. But this lock is out of operation since 2006 and to be rebuilt
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[CLASMEIER. H.D. 2008]. It will be reopened in late 2012 with increased lock dimensions. Coastal
going vessels up to 5,000 dwt and inland vessels up to 135 m length can be locked afterwards. Since
closing the Nesserland Lock the number of lock operations via the Large Sea-Lock has more than
doubled.
Figure 7: Number of locking vessels between 2003 and 2008
The major question is how to handle big vessels while the new lock is under construction? The
importance of the Port of Emden for car-carrier, bulk-carrier for gravel, forest products etc. and a more
and more increasing number of wide supply pontoons to bring wind power elements to the offshore
wind farms under construction require a 24 h lock operation all days. Fig. 7 gives an idea of the very
busy lock operation today. How can the lock be operated sufficiently, due to the increasing ports
throughput?
Considering the fact that the offshore activities in the German Bight in installation of wind parks and
the transport of aggregates, foundations elements and site supply, it is forecasted that the number of
ships being locked between the inner to the outer harbour will increase by nearly 300% for the coastal
and ocean going vessels. Traffic of inland vessels wills more than doubled in the next 50 years (Fig.
8). Pleasure boats, port operation and tug boats are not being considered because the smaller
Nesserland Lock will go in operation latest in 2012.
Figure 8: Forecast of lock operations between 2008 and 2056
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A temporary shut down of the lock operation for more than one week will be not accepted by the port
operating companies. Renewing the lock requires a “normal” lock operation all over the construction
period. The minimisation of time for rebuilding demands a parallel work at both lock heads and the
lock chamber, but this cannot be reconciled with the demand of locking at any time. Thus a continuous
locking operation everyday results in a lengthening of the construction time:
1. build first the outer lock head on a pontoon and float it
2. build second the inner lock head, float it and position both in a building-pit
3. build first one chamber wall without damaging the side culvert
4. remove the chamber wall after the new lock-heads have gone into operation and give the
chamber-wall free for vessel mooring
5. build the other chamber wall in the same manner and finishing with equipment installation
To realize this construction progress several questions are to be answered:
 Is it possible to work in this manner?
 What kind of construction technique is the state of the art?
 What types of special equipment like huge floating pontoons, heavy floating cranes or docks
are available?
 What are about the risk for the port and the operators if one step isn’t successful and the given
closing time is not enough (may be three or four weeks instead one week)?
 Are the costs for the project within the bounds that will be given by the government or the
banks?
The feasibility study and this paper as an extract try to give an answer, that it can be possible to build
the lock under the conditions of port operation.
2.3 The Demands of Dikes Safety
The coast-line in the German Bight is protected against storm surges by dikes. The opening of the
dike for any kind of harbour entrances like a lock demands the same safety however as the dike itself.
Some disastrous floods in the last century (the Holland flood in 1953, the German floods in 1962 and
1976 and at last the All-Saints-Flood in the Ems-Estuary in 2006) caused the calculation of a new
design water level for storm surge barriers and locks. The lock-head platform of the “Large Sea-Lock”
actually is at NN3 + 6.00 m; a masonry and concrete flood wall is able to withstand a water level of NN
+7.00 m. But the new calculation of the design water level has shown that the new dike crest must be
at NN + 8.10 m.
Therefore the new lock-head platform has to be elevated by more than two meters against the old
one. The access-ramps to cross the lock-gates require more development length for the maximum
slope between 5% and 6 %.
Dikes safety in Germany means that an opening in a dike must be protected redundancy by at least
two barriers or gates. In case of a lock it must be possible to have two gates in the outer head or to
connect the one-gate outer and inner head by a lock surrounding dike.
The access harbour in front of the Large Sea-Lock is very short. It is recommended that the
approaching zone coming from sea should be having three or four times the length of the calculation
vessel or the lock chamber length. Such an approaching zone cannot be realized in Emden. So it is
impossible to build a double gate head at the approach side of the lock. In consequence of this, the
new lock needs a surrounding dike like the existing one of the old lock.
The inner and the outer lock head platform must be adapted to the new dike crest of NN +8.10 m. This
is 4.50 m higher than the existing lock chamber working platform. Steps and ramps down to the
chamber would be very steep, so it is easier to lift the top of the chamber wall by 1.00 m up to NN
+4.60 m. It should be possible to reach the chamber platform in an easy manner by cars and lorry for
future maintenance works. The proposed layout of the new lock is given in Fig. 9.
3 NN = Normal Null, German Gorge – mean sea level
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Figure 9: General Layout of the new Emden Sea-Lock
2.4 The Lock Dewatering System
Today the water exchange in the lock chamber is done by a system of longitudinal culverts on both
sides (Fig. 4) and openings in the wall at 1.50 m above the bottom. The culverts are also used to bring
water into the harbour at high tide and for discharging, in case of too much water in the Hinterland
dewatering system. A pumping station can be used to assist the operation. The normal dock water
level is 0.40 m below high water level in the Ems-River.
Renewing of the lock-chamber walls without a new filling system is impossible, as well as building a
new filling system as longitudinal culverts like today.
There are two solutions:
 Installing some sluice gates into the new lock gate or
 Building of a vertical partially or total movable lock gate and using the whole gate as a valve
(TARRAS, Ch. 2009)
Before closing the culverts in the chamber wall, the new lock head must be functionally equipped for
filling operation needs. This is the main challenge to the whole project. Afterwards the old chamber
walls with the longitudinal culverts can be taken out off function and the masonry in front off the new
chamber wall can be removed.
2.5 New Chamber Walls
The existing chamber walls are founded on a heavy block of light reinforced concrete. The foundation
level is adapted to the soil conditions of the Holocene (Fig. 10).
The concrete quality is not very high (resistance < 5 kN/m²). The wall itself edging the lock chamber is
made of masonry used as sheathing for the rising concrete block wall. Some essays in the 1980th
have shown that it must be possible to cut this concrete with a diaphragm wall cutter and fill the trench
with a bentonite suspension. So it is foreseen to cut it behind the culvert (the culvert must stay in
operation until the new lock head is finished) and set a prefabricated concrete element with a width
between four and seven meters into the trench. The element should already be equipped with
keyways for bollards, ladders and fenders. Modern mobile cranes are able to lift up elements to 500
tons.
The trench should not be brought down deeper than the old foundation, which can be used as a lower
retaining element to take of the earth and water pressure behind the new wall.
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Figure 10: Typical cross section of the old lock chamber walls
The upper anchorage of the new chamber wall will be composed by a double pile system. All three
elements will be connected by a concrete deck at about two meters below the low tide water level. The
chamber wall can also be made out of prefabricated elements, but as well as an in situ concrete
construction. Another possibility could be a sheet-pile solution with a combined wall. In this case the
sheet-piles must be driven by vibration deeper into the ground because this system requires a deep
rigid restraint of the piles (Fig. 11).
Figure 11: 3D Animation of new and old chamber wall
All work should be carried out before the front of the lock chamber wall will be removed down to the
level of the existing lock floor. By means of continuously lock operation demand the both sides of the
lock chamber cannot renewed totally at the same time. A gradual working (15 to 20 m) is necessary.
2.6 The Lock Heads
The most difficult and ambitious part of the renewing concept will be the construction of the new lock
heads. The existing heads and gates are in operation in any time, so is no possibility to build this
heads in situ. It needs a prefabricated solution like we have found it at Boulogne/France in 1972 or at
Oslebshausen/Germany in 1981 [PIANC 1985] which implies the following:
A floatable concrete element could be building in a building pit (1), in a dry or in a floating dock (2) or
on a lifting platform (3). The element can be brought into the water (2 and 3) or the water can be
brought to the element to let it float (1). The easiest way is to form a building pit - (this could be an old
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harbour dock), build the element and float the pit, but the space being required is not available
anymore in the port of Emden. In the 90th it was foreseen to build a complete small lock in the
excavated and dried “Jarßum Dock” and bring it into the Large Sea-Lock after a new sea-lock would
be built. But today the Jarßum Dock is needed for harbour operation and the construction of windpower
elements. Another solution must be found.
The availability of big floating pontoons world-wide brought the idea to build a floatable lock-head on
such a pontoon. Due to the draft of the pontoon the whole lock-head could be built in one step or it
must be built in two steps on separate pontoons by dividing the head in a head entrance part and a
gate-chamber part. Parallel to the construction works at the pontoon the new site for the lock head in
front of the old lock-heads must be prepared. A new pit must be protected by steel sheet piles and dug
it then down to the foundation level. This solution doesn’t require any separate pile foundation
because a resistant Holocene sand layer allows a gravity foundation.
The new lock-head generally should be divided into two parts for a more reliable work, the lock
entrance section and the gate-chamber section. Two parts also allow some more flexibility in port
operation.
In a first step the entrance section must be positioned beside the new entrance in the gate chamber
building pit. The element needs to be equipped and then be transverse into the lock entrance. To
realize this operation it is necessary to close the lock for some (4 or 5) days. In the second step the
gate chamber element is to position in the same manner into the building pit and then to be connected
with the entrance element.
At last the gate can be placed into the gate chamber by the aid of a huge floating crane because its
weight will be between 1,600 and 2,000 tons. After it is being finally equipped it is possible to close the
lock and to guarantee the exchange of water by the valves in the roller gate. If this is done at either
head the longitudinal culvert can be taken out of operation and the old lock wall can be removed.
2.7 The new Lock Gates
The type of the lock gate construction is given by the general layout of the lock. In our situation it is not
possible to build a lock with mitre gates because therefore the total length of the lock would increase
up to more than 400 m. There is no space for such a long lock, neither in the approach port nor in the
harbour dock. Another point is that those mitres gates with an opening of more than 45 m have never
been built in the past while the opening of the new Emden Sea-Lock will measures 55 m. Only a roller
gate, a sliding gate or a floating gate is able to close this opening.
In this feasibility study the best solution for the gate construction and its moving system should be
found out. All great sea-lock gates have been built in the past are roller gates, either with two under
water wagons or with an underwater wagon and an upper wagon (wheel barrow principle). The wheel
barrow principle has the advantage that only half of the guiding rails are under water and the others
half on the top of the gate chamber. In this study the wheel-barrow system is chosen. The wheelbarrow
can be driven at the top by a mechanical rope, by a chain or directly with gear and gear rack.
The lock gates are floatable to minimize the operation weight and the load on the rails. In operation
they are ballasted and for maintenance they can be floated and brought into a floating or a dry dock.
But it should also be possible to dock them in the gate chamber for easy maintenance works.
Some years ago DEHOUSSE (1985) made a proposal to build self propelled lock gates. This system
could also be recommended for the new Emden sea-lock. Several of investigation and development
work must be done in this case.
Today in Bremerhaven/Germany a new lock (Kaiserschleuse) is under construction and will be
equipped with a divided roller gate. The upper part of the gate can be lifted by 50 to 70 cm to give free
a wide valve for water exchange. At balanced water-level the upper part of the gate is to set down and
the gate will be driven into the gate chamber to unblock the lock entrance (TARRAS 2009).
This system also should be discussed in the final design matter, but today in the feasibility study we
use the conventional method of several valves in the gate. The operation experiences (PIANC 1985)
at the locks of Wilhelmshaven, Cuxhaven and Oslebshausen (all in Germany) have shown that lock
gate valves can be a good solution if the water level difference is not too high. The normal lock
operation water levels in Emden will be at NN +1.50 m by high water at NN -2.00 m by low water. The
maximum water levels will be at NN +3.00 m by high water and at NN -2.50 m by low water. For this
water level difference (dock water level NN +1.10 m) it is possible to concentrate the turbulence in the
direct surrounding of the valves by special stream dissipaters (Fig. 12).
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Another point of interest is also very important. There is the challenge to cross the lock by a road for
heavy trucks. Building a movable bridge across the lock chamber cannot be accepted because the
useable length of the lock chamber will be minimized for port operation. The only solution is to prepare
the lock gates for road crossing and if possible with two lanes to accept oncoming traffic. There are
several lock gates in operation for truck traffic worldwide but only for a less busy traffic. In our case it
is expected, that the lock crossing traffic will increase which is important for the future port
development. The above discussed movable bridge could only be realized at harbour side in front of
the lock head. But this decision should not be opened in this study.
May be due to this topic the discussed self propelled gate cannot be realized. Nevertheless any kind
of gate construction must be equipped with very well sophisticated under carriage (Fig. 12) and also
with very good roller tracks for the wagon or by high resistant sliding strips made of polypropylene.
For passing over the gate platform by trucks it is necessary to build an interaction section between the
approach and the gate itself. It needs a separate platform which is movable (lift the platform to open
the lock entrance and to roll the gate into the lock chamber). This platform is the connection between
the road and the lock gate if busy road traffic shall be guaranteed.
Figure 12: Lock gate construction; gate cross section (left), under carriage (right)
3. EXECUTION WORKS
3.1 The Demands of the Port Operation
The main topic before starting with any kind of execution works for the new Emden sea-lock is to
realize the new Nesserland Sea-Lock. Only with the guarantee for operation of coastal and inland
vessels and also for thousands of pleasure boats it will be accepted by the port operators any
disturbance by work around the Large Sea-Lock.
The challenge for the lock planning staff and the future contractor will be the demand of a lock
operation most time during the construction phases. Most works have to be carried out while vessels
are being locked. The water level will change permanently and the room for staging, driving elements
etc. will be very narrow.
An unhindered port operation is very important and has absolute priority. The lock renewing has to go
into the second row and higher costs for a new lock will therefore be accepted,
3.2 Time Schedule
The discussion with the port operators has shown that there normally is no possibility to renew the
Large Sea-Lock without any disturbance of traffic. Doing nothing means, the time of the total
breakdown of the lock will come in the next 15 or 20 years. In the worst case this can already happen
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tomorrow. Port operation will be impossible for several years with dramatic economical consequences
in case of a total breakdown.
The construction phase should to be minimized; this is possible by acceptance of several total
closings of the lock for some days (3 to 10 days). Early forecasting of the disturbances makes this
possible for the port operators to be scheduling the vessels approaches. The disturbance of sea traffic
for not more than four years should be accepted.
Because today the crossing of the sea-lock for heavy vehicles is not possible, the closing of the lock
for cars and small lorries will not be a problem. For the total construction work a period of maximum
three years is provided. The installation of equipment for the gates crossings will take another year. So
totally it needs nearly 4 years to realize all works.
3.3 The Lock-Head Construction
As described above, the lock heads (entrance and gate chamber) should be constructed as large
prefabricated concrete elements; which requires very large pontoons or a building pit. Large pontoons
should be available but for a building pit in the area of Emden is no space. The feasibility idea is to
build on the pontoons four elements for the lock heads step by step as soon as possible. In the
meantime in front of the inner head and the outer head of the old lock building pits for the new heads
have to be setup by sheet-piling systems. They have to be excavated and a layer of sand has to be
brought on top of the bottom. The lock head sections (entrance section) can be floated into the
building pit of the gate chamber (Fig. 13). The assistance of a heavy load floating crane for this
manoeuvre is recommended.
Figure 13: Floating caissons for lock-head and gate-chamber section, background left:
building pit in front of the old lock head with lock operation guarantee
The section must be equipped finally as far as possible and than moved over by floating into the lock
entrance and filled with sand and concrete against uplifting. A pile foundation is not necessary,
because the foundation level inside is a sustainable sand layer. The second step is to float the gate
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chamber section into the gate chamber building pit in the same manner. Both sections are to connect
and equipped with all machinery elements. In the third step the lock gate can be floated into the gate
chamber and be put into operation.
The works at the inner and outer head could be carried out almost parallel. During the disturbance
phase at the outer head the time can be used for doing execution works like sheet-pile driving at the
inner head. After starting the operation of the new lock heads and especially the sluice gates, the lock
chamber can be filled and emptied by them.
But one thing still remains unexplained: the problem where the construction site for the lock heads can
be situated. The only possible areas are an old shipyard in the back of the port or a special pontoon
anchored nearby in south of the Large Sea-Lock at the Southern-Quay. If the draught of the lock head
elements doesn’t exceed 12 m or less they can be floated from the yard to the foundation pit in front of
the old heads. In case of a pontoon a deep sinking pit to bring the head elements into floating must be
dredged.
3.4 Lock Chamber Walls
After the new lock gates with its valves are in operation the time has come to remove the old system
of the longitudinal valves. The new lock chamber walls can be built (Fig. 14).
Figure 14: Detail of the old lock chamber wall interpenetrated by the new construction
This includes the following steps:
 One side of the old lock chamber walls will be cut for setting up a new wall inside this trench.
The piling system will be driven and connected with the wall in the trench to the new quay-wall
head. This work can be finished before the front part of the old wall must be removed.
 After taking the new lock heads with their filling system into operation, the old chamber wall in
front of the new one can be removed. This work must be carried out very carefully, because it
is to avoid that blocks of masonry or concrete fall down into the lock chamber and disturb the
vessels navigation. Afterwards the new chamber wall will be finally equipped for locking
vessels with bollards fenders and other navigation aids.
 In a third step the described works are to repeat on the other side of the lock chamber. To
minimize the construction time it might also be possible to cut the wall and set the new one
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into the trench. To guarantee a permanent lock operation it will be impossible to work on either
side simultaneously.
 Because the floor of the lock will not be changed, an unrestricted lock operation will be
possible after finishing the walls and cleaning the lock chamber.
The total construction time for the lock chamber walls will be estimated at 16 months.
3.5 Lock Equipment
The total time to renew the old Emden Great-Sea-Lock will be about four years. This must be time
enough to equip the lock with all things required for a safe lock operation and vessels navigation. For
some months it must be possible to drive the lock gates and the valves directly from the upper
carriage in the gate chamber. In this time the central operation desk is to install in the lock tower to
operate in the future all locks, pumping stations and movable bridges in the Port of Emden. All this
mechanical equipment will be connected by a so called “lock-socket” to the operating desk.
Lock equipment consists of the gates and valves and their machinery and electrical surrounding the
fender and bollard system. The operating desk and the surveillance system with cameras and
loudspeakers will be installed in the lock operation centre. A special computer system will record all
anomalies and functions as UMTS, road signals etc... Due to the actually operating requirements
during the execution phase a facility security plan seems necessary.
3.6 Dike Building and Traffic Infrastructural Works
The existing lock dike with its contemporary crest at NN +6.50 m is to heighten by 1.60 m. The slopes
at either side of the dike are too steep, so the dike also is to broaden at its basis. Because there is
room enough between the dike axis and the new lock chamber wall, it is possible to widen the dike in
direction of the lock axis. Trees at the other side of the dike don’t need to be cut down.
The crest of the southern lock dike must be broader. The dike shall be used as embankment for the
road between the lock heads (Fig. 9). The future importance of the road which will connect the outer
and the inner harbour demands a width of more than 8.50 m, including two lanes for cars and a
separate lane for pedestrians and cyclists.
The road comes up from both sides at a level of NN +3.60 m and rises to the level of NN +8.10 m. A
difference of 4.50 m requires a length of the ramps of at least 75 m. The bends have to be formed with
a radius of at least 25 m for 18-m trucks. The road construction will be the last step of the renewing
process.
3.7 Estimated Costs for Renewing the Lock
The feasibility study for a new lock construction but also for any kind of civil engineering work should
also give an estimation of the costs.
There are four main topics to pay attention to:
 Four floating elements for the lock head; assembling in Emden; no transport from far away.
160 millions €
 Three lock gates; each one of 2,000 tons weight
75 millions €
 600 m lock chamber walls; 100.000 €/m
60 millions €
 600 m of dikes; 1.000 m of lanes
30 millions €
The design evaluation with an amount of 300 - 350 millions €, gives an idea to the port finance
department that the renewing of the Large Sea-Lock to the Port of Emden needs a special financial
budget in the years from 2018 to 2025. The estimated costs seemed not too much because the
renewing of the Kaiserschleuse at Bremerhaven, which is currently under construction is calculated
with some 230 millions €. This lock has gone out of operation when the execution works has started in
2007.
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4. CONCLUSIONS
The “Large Sea-Lock” in Emden has gone in operation in 1913. It must be renewed within 2015 and
2025 maintaining the full operation process of the Port of Emden with more than 5.000 locking each
year. After the renovation of the second Emden lock, the smaller Nesserland Sea-Lock in the year
2012, the planning for the Large Sea-Lock will have to start. Today the responsible engineers for the
old sea-lock have to give their experience to the younger colleagues. They have to assume the
challenge to renew the heart of the port. Without a Large Sea-Lock over a period of more than several
weeks the port of Emden would start ailing and after some month without the possibility of loading and
unloading big vessels the port would have lost all its importance for modern sea-borne traffic.
The detailed planning with all parts of survey, beginning with the environmental impact assessment
study and ending in several modified studies e.g. for settlement of lock heads or the development of
stream flow in the culverts has to start in the next years. A feasibility study will give first answers of
constructions methods to build the lock heads and the lock chamber, for the lock gate construction
and operation and at last the difficulties to build the lock under operation.
The responsible politicians and decision-makers must be well instructed to understand that a renewed
Emden Sea-Lock will require an higher investment than building a lock on the “green meadow” or as
Greenfield strategy. An amount of 300 to 350 millions Euros is calculated under the current conditions.
The realisation of the new construction means, that a time of disturbance to the port operation traffic
for three move likely four years must be mentioned.
References
Clasmeier, H.-D. (1985). Neubau eines Schiebetores für die Große Seeschleuse in Emden, HANSA
Heft Nr.5, Hamburg
Clasmeier, H.-D. et al. (1987). The Dollard-Dock Project, PIANC Bulletin Nr. 59, Brussels
Clasmeier, H.-D. (2008). The Renovation of the old Nesserland Sea-Lock at Emden Port, ICCE 2008,
Hamburg
Dehousse, N.M. (1985). Les Ecluses de Navigation, L.H.C.H. Université de Liège
Hübner, H.J. (1991). Die Grundinstandsetzung der Großen Seeschleuse in Emden, Jahrbuch der
Hafenbautechnischen Gesellschaft; HTG Bd.46, Hamburg/Berlin
PIANC (1986). Final Report of the International Commission for the Study of Locks, PIANC, Brussels.
PIANC (2009). Report No.106, Innovations in Navigation Lock Design, PIANC, Brussels.
Tarras, Ch. (2009). Neubau der Kaiserschleuse in Bremerhaven, PIANC Kolloquium 2009, Bonn,
Germany
Zander, W. (1914). Erweiterung des Emder Hafens, Zeitschrift für Bauwesen, 64. Jahrgang, Heft 10 to
12, Berlin

 

Ohne Fotos und Bilder

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Feasibility Studie zur Erneuerung der “Großen Seeschleuse ” in
Emden
H.-D. Clasmeier, Niedersachsen-Ports, Emden, Germany1
ABSTRACT
Der Hafen Emden ist der westlichste deutsche Hafen an der Nordseeküste. Er ist für Seeschiffe erreichbar
über die Ems, die sich hier zum Dollart öffnet und die deutsch-niederländische Grenze bildet.
Der Hafen teilt sich in den über Schleusen zugänglichen Binnenhafen (rd. 530 ha) und das unter Tideeinfluss
stehende Becken des Außenhafens sowie die Hafenanlagen unmittelbar an der Ems (rd.
200 ha). Der innere Hafen hat eine große Bedeutung für die Produktion und den Umschlag von Bauelementen
für die Windkraftindustrie und von Offshorebauteilen im Werftbereich der Nordseewerke.
Der Außenhafen ist mit einem Umschlag von mehr als 1,0 Mio. Kraftfahrzeugen das drittgrößte europäische
Drehkreuz in der Autodistribution. Im Jahre 2008 betrug der Umschlag mehr als 7,0 Mio. Tonnen.
Trotz der allgemeinen weltweiten Regression ist in 2009 die Umschlagmenge nur gering zurückgegangen
Die Entwicklung des modernen Seehafens Emden nahm ihren Ausgang im Jahre 1882 mit dem Neubau
der “Nesserlander Schleuse“ (Einfahrtbreite = 14,00 m; Nutzlänge = 110,00 m). Die Große Seeschleuse
mit einer Einfahrtbreite von 40,00 m und einer Länge von 260,00 m zwischen den Schiebetoren
nahm 1913 ihren Betrieb auf und stellte damit den wichtigsten Zugang zum expandierenden Hafen
dar. In Abhängigkeit von den leistungsfähigen Schleusen wurde der Hafen Emden der wichtigste Umschlagplatz
für den Erzimport zu den Hütten des Ruhrgebiets sowie den Kohleexport von dort. Mit
über 16,0 Mio. Tonnen erreichte der Hafen Emden in 1975 die bisher größte Umschlagmenge.
Hafen Emden; Masterplan der neuen Seeschleuse oben links
Immer größere Abmessungen der Massengutschiffe im Erz- und Kohletransport in den 70er Jahren
des letzten Jahrhunderts machten jedoch den Hafen zunehmend unattraktiv. Wegen der begrenzten
Fahrwassertiefe in der Ems mussten die Schiffe vor Borkum mit sehr viel Aufwand geleichtert werden.
1 Betriebsleiter Engineering, Niedersachsen-Ports, Emden, Germany hclasmeier@nports.de
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Dieses war Veranlassung für die Planung des Dollarthafens, der mittels einer rd. 15 km seewärts gelegenen
neuen großen Schleuse die Zugänglichkeit für Schiffe bis 150.000 tdw sicherstellen sollte.
Die Realisierung war in den Jahren 1991 bis 1998 vorgesehen. Die „Große Seeschleuse“ sollte dann
außer Betrieb genommen und zurückgebaut werden.
Bereits 1980 wurde durch die Bundesanstalt für Wasserbau (BAW) in Karlsruhe festgestellt, dass
dank des baulichen Zustandes der “Großen Seeschleuse” noch ein Betrieb von 25 Jahren garantiert
werden könnte, wenn kurzfristig ein umfangreiches Sanierungsprogramm umgesetzt würde. Umfangreiche
Untersuchungen hinsichtlich der Qualität des Mauerwerks und des Stampfbetons der Schleusenkammer-
und Schleusenhauptwände, des Baugrundes, der Schleusentore und deren Führungselemente
wurden vorgenommen. Die Einlaufkanäle und deren Verschlüsse wurden trockengelegt und
deren Zustand erkundet.
Zwischenzeitlich wurde im Jahre 1990 das Dollarthafenprojekt aufgegeben, die „Große Seeschleuse“
musste folglich für den Hafen Emden erhalten bleiben. Das Sanierungsprogramm wurde in den Jahren
zwischen 1993 und 1997 mit einem Kostenaufwand von rd. 58 Mio. DM (rd. 30 Mio. €) realisiert.
Neue Schleusentore wurden gebaut, die Torlaufschienen wurden mittels des Einsatzes von Druckluftarbeitskammern
erneuert und die Schleusenkammerwände aus vorgesetzten Süllkästen heraus umfangreich
saniert.
Nach nunmehr 15 Jahren Schleusenbetrieb im sanierten Zustand muss die Frage nach einem weiteren
Sanierungs- oder Erneuerungskonzept gestellt werden. Eine komplett sanierte oder erneuerte
Schleuse sollte spätesten im Jahre 2025 in Betrieb gehen. Verschiedene Aspekte einer Erneuerung
sollen im Folgenden angesprochen werden.
Bedingt durch die aktuelle Sanierung der zweiten Emder Schleuse bei Nesserland muss die “Große
Seeschleuse” heute rd. 15.000 Schiffe jährlich aufnehmen. Davon sind 2.500 große Seeschiffe und
7.500 sind Binnenschiffe. Das Ergebnis einer ersten Machbarkeitsstudie sollte spätestens Ende 2010
vorliegen, damit die entsprechenden Rahmenbedingungen hinsichtlich der Kosten und der Genehmigungen
abgesteckt werden können. Wesentlich ist, dass die Erneuerung der Schleuse unter vollem
Hafenbetrieb vorgenommen werden muß.
Dieses wird innovative Lösungen in der Bautechnik erforderlich machen. Erste Überlegungen sind der
Einsatz großformatiger schwimmender Elemente für die Schleusenhäupter, die vor die vorhandenen
gesetzt werden müssen. Weiterhin ist wichtig, dass die neuen Schleusenkammerwände erstellt werden
müssen, ohne das vorhandene Füllsystem zu beinträchtigen. Dieses bedeutet wiederum, dass die
Schleusendimensionen größer werden müssen. Eine Schleusenkammerlänge von 320 m und eine
Durchfahrtbreite von 55 m eröffnen insbesondere der in Emden wachsenden Offshoreindustrie zusätzliche
Chancen im Wettbewerb.
Der vorliegende Beitrag beschreibt die Randbedingungen aus der Geometrie und dem Betrieb der
alten Schleuse und stellt ein Konzept zur Planung und zum Bauablauf einer neuen Schleuse vor. Er
gibt den Stand der Planungen zum Herbst 2009 wieder. Weitere Einzelheiten sollen im Vortrag auf der
PIANC Konferenz in Liverpool vorgestellt werden.
Neue Schleusenkammer mit Kreuzfahrtschiff AidaLuna
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EINFÜHRUNG
1.1 Der Hafen Emden
Der Hafen Emden befindet sich im südwestlichen Teil der deutschen Bucht unmittelbar im Grenzbereich
zu den Niederlanden an der Mündung der Ems in den Dollart (Bild 1). Die angrenzende Landschaft
ist seeseitig durch das Wattenmeer und landseitig durch weites flaches Marschland geprägt,
das sich zu einem großen Teil unterhalb des mittleren Tidehochwassers befindet. Sie trägt die Bezeichnung
Ostfriesland und ist zur See durch viele kleine Fischereihäfen und dem Haupthandelshafen
Emden geöffnet.
Bild 1: Lage des Hafens Emden
Die räumliche Ausdehnung des Hafens beträgt mehr als 2.000 ha, davon sind heute jedoch nur 700
ha für Hafenzwecke genutzt. Es stehen über 20 km als Kaimauern, offene Piers oder durch Böschungen
gesicherte Uferabschnitte mit rd. 40 Liegeplätzen für Schiffe verschiedener Größe bis zu einer
Tragfähigkeit von 80.000 tdw zur Verfügung. Der Hafen verfügt über zwei Seeschleusen, verschiedene
bewegliche Brücken und mehrere durch Tore verschließbare Öffnungen im Hochwasserschutzdeich.
Weltweit hat der Hafen Emden die größte Bedeutung für die Distribution von Kraftfahrzeugen
der deutschen Volkswagengruppe. Es werden allerdings auch Fahrzeuge anderer Hersteller umgeschlagen.
Bild 2: Hafen Emden, Autoport (links); Umschlag von Windkraftanlagen (rechts)
Im Jahre 2007 betrug der bisher größte Umschlag an Kfz im Im- und Export etwa 1.100.000 Stück.
Weitere für den Hafen Emden zu nennende bedeutende Güter sind Waldprodukte (1,0 Mio. t), verflüssigter
Marmor (1,0 Mio. t) und einige hunderttausend Tonnen flüssiger Düngemittel und Magnesiumsole.
Von zunehmender Bedeutung ist der Umschlag so genannter Projektladung, unter der Elemente
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für den Bau von Windkraftanlagen wie Türme, Generatoren und Propeller zu verstehen sind (200.000
m³). Hier wird die Menge, teilweise wegen des sehr geringen Gewichts nur in Kubikmetern angegeben.
Die Nordseewerke sind ein bedeutender Betrieb für den Bau von Offshorekonstruktionen für die
Rohstofferkundung und die Gründung von Windkraftanlagen in der offenen See aber auch für die
Wartung und Reparatur von Schiffen und anderen schwimmenden Einheiten (Bild 2).
Der weltweite Einbruch in Handel und Produktion in den Jahren 2008 und 2009 ging auch an Emden
nicht spurlos vorüber. Mit weniger als 20% Umschlagverlust in der Menge traf es den Hafen Emden
vergleichsweise gering, da die höhere Wertschöpfung, insbesondere bei der Projektladung den Einbruch
teilweise wettmachen konnte (Bild 3).

ore and coal
Bild 3: Hafen Emden, Umschlagentwicklung in Tonnen (1991 bis 2009)
Weil die Entwicklungsmöglichkeiten in den heutigen Grenzen des Hafens sehr eingeschränkt sind,
wurde im Jahre 2008 ein neues Hafenentwicklungskonzept aufgelegt, das eine Ausweitung der Hafenaktivitäten
seewärtig entlang der Ems bis zum etwa 17 km entfernten Rysumer Nacken in der Zukunft
vorsieht. Diesen „Masterplan“ umzusetzen wird allerdings eines Zeitraumes von mindestens 15
Jahren bedürfen. Damit verbunden sollte eine intensive wirtschaftliche Stärkung des ostfriesischen
Raumes einhergehen. (CLASMEIER, H.D. 2008).
1.2 Die Geschichte der „Großen Seeschleuse“ in Emden
Die dramatische Verschlickung des alten Emder Fahrwassers zwischen dem damals innerstädtischem
Hafen und dem Dollart veranlasste den Rat der Stadt Emden um 1840 zu entscheiden, dass ein neues,
tideunabhängiges Fahrwasser zur Ems gegraben werden sollte. Dieser Kanal wurde nach Süden
im Bereich der Einmündung in den Dollart anfangs durch eine Dockschleuse, ab 1888 dann durch
eine parallel dazu angeordnete einfache Kammerschleuse abgeschlossen. Dieses ist als die Geburtsstunde
des modernen Hafens Emden zu sehen.
Zunehmende Schiffsgrößen aber auch eine schnelle Entwicklung de Hafens erforderten bereits anfangs
des 20. Jahrhunderts den Bau einer zweiten größeren und von den Wasserständen absolut
unabhängigen Kammerschleuse. In den Jahren zwischen 1907 und 1913 baute die damalige preußische
Wasserbauverwaltung, auch unter den Zwängen der Expansionsgelüste von Kaiser Wilhelm II.
die heutige „Große Seeschleuse“ (ZANDER, W. 1914). Mit den Abmessungen von 260 m Länge zwischen
den Toren und einer Kammerbreite von 40 m war sie in der Lage vier „kleine Kreuzer“ der Emden-
Klasse gleichzeitig aufzunehmen. Heute lassen die Abmessungen die Schleusung eine voll abgeladenen
Schiffes von 50.000 tdw Tragfähigkeit zu (Bild 4). Die Schleuse war zu ihrer Zeit eine der
größten Seeschleusen weltweit. Sie ist an jedem Haupt mit einem Schiebetor ausgestattet. Die
Schleusenhäupter sind mittels Deich miteinander verbunden (Bild 6).
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Bild 4: 3-D Modell der Großen Seeschleuse in Emden
Die Schleuse ist täglich 24 Std. in Betrieb. Dieses bedingt einen erheblichen Verschleiß der Führungsschienen
für die Tore, der bereits 1950 zu einem schweißtechnischen Auftrag auf die Schienen
führte. In den Jahren zwischen 1984 und 1997 wurden sämtliche Laufschienen in den Häuptern in
Unterwasser-/Druckluftarbeit erneuert (CLASMEIER, H.D. 1985; HÜBNER, H.J. 1993).
Bild. 5: Bau der “Großen Seeschleuse”; Schleusenkammer(links), Längskanal (rechts)
In den frühen 80er Jahren des letzten Jahrhunderts war vorgesehen, die Ems durch den Dollart umzuleiten,
auf dem Geiserücken zwischen Emder Fahrwasser und Dollart einen Deich zu bauen und das
so entstehende Hafenbecken an der Knock im Übergangsbereich zwischen Dollart und der freien
Nordsee mit einer sehr großen Schleuse dem Tideeinfluss zu entziehen. Dadurch sollten erhebliche
Kosten für Unterhaltungsbaggerungen im Emder Fahrwasser eingespart werden (CLASMEIER, H. D.
et al. 1986). Die Baukosten für das so genannte Dollarthafenprojekt wurden seinerzeit mit 1,4 MilliarPIANC
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den DM (0,75 Mrd. Euro) veranschlagt. Damit entfiele die Erneuerung der inzwischen in die Jahre
gekommene „Großen Seeschleuse“ in Emden. Die hohen Investitionskosten und die wegen der
Grenzsituation ungeklärten völkerrechtlichen Fragen zwischen Deutschland und den Niederlanden,
aber auch der mangelnde Rückhalt in der Emder Hafenwirtschaft waren Anlass, das Projekt im Jahre
1990 abzubrechen. In der Konsequenz wurde der Hafenplanung und dem Hafenbetrieb klar, dass
nunmehr die „Große Seeschleuse“ zunächst kurzfristig umfangreich saniert (siehe oben) und in absehbarer
Zeit auch erneuert werden müsste.
Durch die Außerbetriebnahme der “Nesserlander Schleuse” infolge mangelnder Betriebs- und Standsicherheit
im Jahre 2006 ist die Bedeutung der “Großen Seeschleuse weiter gestiegen. Die kleinere
Nesserlander Schleuse wird zurzeit erneuert und den Schiffsgrößen in der Binnen- und Küstenschifffahrt
angepasst. Die Fertigstellung ist bis zum Jahre 2013 zu erwarten. Dieses bedeutet aber, dass
die “Große Seeschleuse” über einen Zeitraum von 7 Jahren zusätzlich etwa 12.000 Schiffe mehr zu
schleusen hat und durch heute 6.500 Schleusungen anstelle von bisher etwa 4.500 Schleusungen
ihre theoretische Lebenszeit zusätzlich verringert wird. Spätestens im Jahre 2025 hat die Schleuse
das Ende der technischen Betriebszeit erreicht.
Die “Große Seeschleuse” wurde in einer geböschten großen Baugrube hergestellt, die gegen höhere
Wasserstände durch einen Deich geschützt war. Das gesamte Bauwerk ist flach gegründet. Der Gründungshorizont
wurde jeweils der Bodenschichtung angepasst. Die Bauwerkswände sind sowohl für
die Schleusenkammer wie auch für die Torkammern als Schwergewichtsmauern in Stampfbeton mit
vorgesetzter Mauerwerksschale hergestellt (Bilder 4 und 5).
2. Wesentliche Randbedingungen für die Erneuerung der Schleuse
2.1 Generalplan
Die Hafenbauer in Emden wählten anfangs des 20. Jahrhunderts für die Seeschleuse und ihre Zufahrt
von der Ems eine Lage, die auch nach fast 100 Jahren Betriebserfahrung als optimal bezeichnet werden
darf. Die Anzahl von Havarien zwischen Schiffen und Schleusenbauteilen ist nach Durchsicht des
Bauarchivs als gering zu bezeichnen. Größere Schäden sind ausgeblieben. Frühere Planungen zur
Erneuerung der Seeschleuse sahen vor, diese südlich der vorhandenen ohne Beeinträchtigung des
Hafenbetriebes zu bauen. Bedingt durch den Ausbau des Fahrwassers der Ems zwischen Emden und
Papenburg und infolge der unter Naturschutz gestellten Wattenflächen im Dollart u.a. auf dem Geiserücken
lässt sich diese Planung aber heute nicht mehr verwirklichen. Damit einhergehen müsste die
Verlegung des Fahrwassers in das sehr wertvolle und nicht antastbare FFH-Gebiet, das in dem erheblichen
Ausmaße des Eingriffs nicht zu ersetzen ist. Außerdem lässt sich der emsseitige Vorhafen nicht
verlängern. Es verbleibt als einzige Lösung nur die Erneuerung der Schleuse in ihrer vorhandenen
Achse. Die Abmessungen einer künftigen Schleuse werden aufgrund der Aufrechterhaltung des Hafenbetriebs
und der Möglichkeiten der Bautechnik zu entwickeln sein.
Die natürliche Wassertiefe der Ems ohne den Einsatz von Nassbaggergeräten beträgt etwa 6,00 m
unter Seekartennull. Durch umfangreiche Unterhaltungsbaggerungen wird heute eine Fahrwassertiefe
von SKN -8,20 m vorgehalten. Eine Vertiefung auf SKN -9,20 m soll bis zum Jahre 2012 abgeschlossen
werden. Eine Fahrwassertiefe auf SKN -9,70 m ist denkbar, also sollte eine neue Seeschleuse auf
diese Tiefe bemessen werden. Der Binnenhafen und die vorhandene Seeschleuse sind darauf ausgerichtet,
dass Schiffe mit max. 11,00 m Tiefgang gefahrlos die Hafenanlagen auf der Hochwasserwelle
fahrend anlaufen können. Schiffe bis 12,00 m Tiefgang könnten nach Herstellung von Liegewannen
im Außenhafen und direkt an der Ems dort anlegen.
Die Drempeltiefe der Seeschleuse beträgt heute SKN -9,76 m; das entspricht NN -11,96 m. Da der
gesamte Bereich der Schleusenkammer durch Basaltsteinpflaster 40/50 cm gegen Erosion ausgepflastert
ist, empfiehlt es sich, sowohl Schleusenkammersohle, wie auch Drempeltiefe der Häupter
beizubehalten.
Die Einfahrtbreite der Großen Seeschleuse beträgt 40,00 m in den Häuptern und 43,20 m zwischen
den Kammerwänden, die durch Schwimmfender geschützt sind. Der Füll-/Entleerungsvorgang der
Schleusenkammer erfolgt über beidseitige Längskanäle in den Wänden mit Öffnungen oberhalb der
Sohle. Die 3-D Darstellung im Bild 4 gibt eine Übersicht über das Bauwerk. Bei der Diskussion über
die Erneuerung der Schleusenkammerwände zeigt sich, dass bei Aufrechterhaltung des Schleusenbetriebes
in einem ersten Schritt neue Häupter mit Toren und integrierten Torschützen hergestellt werden
müssten. Erst nach deren Inbetriebnahme kann mit den Rückbauarbeiten und der Erneuerung der
Schleusenkammerwände begonnen werden. Die Füll- und Entleerungsvorgänge erfolgen dann über
die Torschütze. Jeweils eine Schleusenkammerwand muss über die gesamte Bauzeit für das

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