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Terminal Construction TechnologyContainer-Terminal (CT) 4

Photo ➊ Impressive port facilities:view of the terminal and its 3237-metre long quay

Photo ➋ Boom at the terminal: container throughput will doubleagain in the near future

Photo ➌ Gantry crane at the quayside:3.5 million containers were handled in Bremerhaven in 2004

Photo ➍ A vessel is prepared for departure:the terminal needs new berthsand more operating area

Photo ➎ Safe harbour in sight:a container vessel on its way to Wilhelm Kaisen Terminal

Photo ➏ Busy shipping route at Bremerhaven:the seaport is one of the largest container terminals in the world

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Bremerhaven gets ready to face the competition CT 4: New berths safeguard the future of a world-class port

In Bremerhaven, a large-scale project is gradually taking shape. The Free Hanseatic Cityof Bremen is investing in its future as a maritime location and expanding its modern portfacilities at the Weser estuary.

The construction of Container-Terminal (CT) 4 is the two-city state’s response to thecontinuing boom at the quays and the forecasts of the transport pundits: over thecourse of the next eight to ten years, container throughput at Bremerhaven is expectedto double yet again, as a result of the global trend towards intense division of industriallabour and the growing demand from newly emergent markets throughout the world.

The longest riverside quay in the world has already been extended by 340 metres toequip the terminal to cope with these developments. However, the construction phasewhich was completed in 2003 proved to be merely the start of a much more extensiveproject: by the year 2008, Bremerhaven’s container quay will be extended northwards to create four new berths for mega-container vessels – a vital investment if the port is tosucceed in the face of increasingly fierce competition.

In 2004, with a volume of 3.5 million TEU, Bremerhaven ranked amongst the largestcontainer terminals in the world. Handling these standardised transport boxes togetherwith related services form the core of the maritime economy in the two-city state of Bremen and Bremerhaven. The world port on the River Weser provides jobs for morethan 80,000 people in the Federal Land of Bremen and surrounding area in Lower Saxony.

The forthcoming increase in throughput to more than 6 million TEU – twice the currentfigure – also means strong economic impetus for the region. As increasing capacity becomes available for use at the future CT 4, the number of jobs dependent on the container business will also continue to rise. Experts predict more than 10,000 new jobsin the greater Bremen/Bremerhaven area by the year 2020 as a result of the terminal extension.

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1681 metres of quay, 90 hectares of operating area New quay follows the course of the fairway – New mouth for the canal

Europe’s fourth-largest container terminal is growing northwards. The site of the futureCT 4 lies in tidal mudflats, on the edge of the Weser navigation channel. In the south,some parts of the new terminal will be built on the dyke foreland.

The quay at Container-Terminal 4 is 1681 metres long. The first 537 metres are a directextension of ”Stromkaje”, the existing riverside quay, after which the new quay turns off to the north-west at an angle of 10 degrees, following the course of the fairway. Extension of the existing terminal will create a new operating area of 90 hectares with adepth of 570 metres in front of Weddewarden.

The new terminal area is crossed by the outer reach of Grauwall Canal, which carriesrainwater from parts of the city of Bremerhaven and the surrounding area in the northinto the River Weser. In order to create one coherent terminal area, the outer reach hasto be rerouted around the new terminal facilities in the east, and will subsequently flowinto the Weser to the north of Container-Terminal 4.

At the north and east of the extension areas, new dykes will be built to protect thehinterland. New mooring basins will be dredged in front of the new container quay toensure sufficient navigable water depth for the ships at all times. A 100-metre long wingwall is planned at the northern end of CT4.

Photo ➊ Scene at the dyke: the terminal is gradually moving northwardsPhoto ➋ Site map: CT 4 will extend to the borders of Lower SaxonyPhoto ➌ Before work begins: view of the dyke forelandPhoto ➍ Germany’s largest port construction site, shot against the light

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Photo ➊ Problematic soil: 400,000 cubic metres of unstablemarsh soil have to be dredged

Photo ➋ Excavating the foundation pit:the dredged material is taken away in barges

Photo ➌ Dredger ”Hansa” in action for the new quay: Its work wascompleted in autumn 2004

Photo ➍ Special-purpose vessels for terminalconstruction: water injection dredger (front) and hopper dredger

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Difficult soil conditions 400,000 cubic metres of unstable marsh soil have to be replaced by sand

Difficult soil conditions repeatedly pose problems for container terminal constructionprojects on the mouth of the River Weser. Down to a depth of 16 metres below meansea level, there are deposits which are generally known as marsh soil. These deposits are inhomogeneous and consist of alternate layers of sand and mud. The sand layers varybetween just a few millimetres and one metre thick.

Although the foundation has better bearing capacity, it is by no means homogeneous.As a result of the ice age, it contains coarse sand, gravel, rubble, glacial loam, clay, siltand silty fine sand.

Special action has to be taken to solve the problem of these unstable layers before construction of the quay and the subsequent working areas. In previous quay construction projects at Bremerhaven, replacing the unstable layers with sand has proved successful. On the Container-Terminal 4 site, soil has to be replaced over a length of approx. 1100 metres, in other words along roughly two thirds of the totalquay length. In the northern part of the planned terminal facility, the upper edge of the stable layers is higher, so that only the thin layers of marsh soil have to be removedthere. All in all, 400,000 cubic metres of unstable marsh soil will be dredged and replaced with sand.

Moreover, all the deep foundations for the quay, crane runway and other structureshave to be adapted to the changing properties of this diluvial soil.

The planning engineers also have to bear in mind that the brackish water at the mouthof the Weser contains large quantities of fine sediment. In parts of the port where thecurrent has been stilled, this can lead to deposits of up to three metres every year. Especially during the soil replacement phase and subsequent backfilling with sand, considerable effort is required to prevent mud from settling or to remove any depositswhich occur. This is done by a special water injection dredger which whirls up the sediment and keeps it suspended.

Sheet piling, batter piles and pier slab Reliable construction – Wave absorber breaks the power of the waves

Construction of the new quay is based on the principle of an anchored wall, backed by a load-retaining slab. Good experience has already been made with this type of construction during earlier projects in the area around the riverside quay. In principle, thenew project will have the same cross-section as terminal extension CT IIIa, which wascompleted in 2003.

On the waterside, heavy sheet piling supported by batter piles forms the central load-bearing element of the quay. Once the wall has been anchored, it can be backfilled withsand. From now on, the water construction site becomes a land site. The pier slab is installed behind the sheet piling; this is a load-retaining slab which is also enclosed by a sheet piling apron on the land side.

A wave absorber is integrated in the concrete structure behind the sheet piling to dissipate the energy of incoming waves and prevent water overtopping onto the quay.The wave absorber principle was developed back in the 1960s when the first phases ofthe quay were built at Bremerhaven and was again assessed during pilot tests in 1997.The wave absorber effectively protects the quay and terminal in case of extremely highincoming storm tides.

The plans also envisage permanently lowering the groundwater to such an extent thatany excess water pressure can be absorbed, even in case of extremely low outgoing tides.

The 100-foot (approx. 30.48 metres) run for the gantry cranes takes the form of a crane runway which is designed as a separate structure behind the quay itself (with deepfoundations of cast-in-place driven piles, Franki System).

Ships and quays that are exposed to strong winds and gales from the north-west have to be reliably protected by fenders. These are suspended in front of the quay, guaranteeing sufficient distance between the wall of the vessel and the sheet piling.

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Photo ➊ Separate structure: the landside crane foundation is built behind the quay structure

Photo ➋ Protection for container vesselsand quay: fender slabs waiting to be mounted

Photo ➌ Terminal construction in Bremerhaven: jack-up platformsare used for the pile driving

Photo ➍ Idea of the scale: construction of the new container quay, showing a ship and gantry crane

Photo ➎ Vibrating and subsequent driving:installing the bearing piles for the CT4 sheet piling

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Photo ➊ Work proceeds: jack-up platform with pile driver and barge Photo ➋ Early 2005: the new sheet piling gradually takes shape Photo ➌ Reliable statics: typical cross-section of Container-Terminal 4 Photo ➍ Tried-and-tested technology: driving in the batter pilesPhoto ➎ Pressed for time: the sheet piling is to be finished by 2006Photo ➏ Moving north: construction of the new sheet piling

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Pile driving under ideal working conditions Jack-up platforms in use – Modern vibration technology reduces noise

The central loadbearing element of the new quay consists of heavy-duty combinedsheet piling (pile row P1), made up of double piles (PSp 1001, steel grade S 430 GP) andintermediate piles (PZa 675/12-23). The double piles are between 35 and 40 metreslong. The sheet piling is anchored by 42 to 46-metre long batter piles (PSt 600/159, pilerow P1a).

The load-retaining reinforced concrete slab (pier slab) behind the sheet piling has deepfoundations consisting of three rows of Peine steel piles (PSt 500/158), set in the length-wise direction of the quay at intervals of 2.31 and 4.62 metres (rows P2 and P3, or 4.62metres (row P4). The piles crosswise to the direction of the quay are spaced at intervalsof 5.00 and 7.60 metres. To increase their loadbearing capacity, these piles have sides oftruncated PSt profiles.

As it is not possible to fill in an area with sand to create a suitable working basis besidethe River Weser fairway, jack-up platforms are used to drive in the piles in row P1 andthe batter piles. These platforms have repeatedly proved their worth during previousquay extension projects, as they are not affected by the waves or the swell of passingships. The jack-up platforms stand on the underwater slope of the soil replacement pit.

Before the sheet piling can be backfilled with sand, it has to be completely connectedwith the batter piles. This is done by means of a tubular cross-member. Once the areabehind the sheet piling has been filled in with sand up to a level of 2.50 metres abovemean sea level, CT 4 becomes a land construction site. The site is protected by the sheetpiling – the top edge of which is 6.70 metres above mean sea level – and the dyke,which has been raised to the necessary height. Further pile driving work – pile rows P2,P3, P4 and the cast-in-place driven piles for the crane runway – is handled by excavator-mounted pile drivers.

To keep the noise within acceptable limits, the use of pile hammers is largely avoided. Instead, modern vibration technology is used to insert the piles. Only along the last fivemetres are the individual piles subsequently driven into place to guarantee sufficient loadbearing capacity. A bellows noise shroud is used when driving in the double piles,which surrounds the piles and substantially reduces the noise.

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Monolithic pier slab and crane runway Special concrete formula – Comprehensive corrosion protection

The reinforced concrete slab (pier slab) with the integrated wave absorber is producedon the infilled sand area using cast-in-place concrete. The pier slab is roughly 80 centimetres thick and 20 metres wide, and is produced in stages of approx. 70 metres.Connecting the pier slab to the sheet piling also involves concreting the batter pilingconnections. Additional anchor steels are welded on to the batter piles.

The back walls of the wave absorber are produced in the same lengths. After the shuttering has been installed for the back wall, the intermediate piles of the sheet pilingabove the pier slab can be removed. Formwork panels are inserted in the spaces as shuttering for the wave absorber ceiling. After the 80-centimetre thick ceiling has beenconcreted, the quay structure – which also forms the line of the dyke – affords the finalprotection against floods at a height of 7.50 metres above mean sea level. The cranerunway has a trapezium-shaped cross-section, which is also concreted in stages ofaround 70 metres.

The pier slab with the wave absorber and crane runway are produced as a monolithicstructure over the entire length of almost 1.7 kilometres. This is possible thanks to a special low-heat concrete mix formula, intensive curing and reinforcement which ensures even distribution of cracks. This monolithic construction principle has alreadyproved successful in previous terminal construction projects in Bremerhaven. It also eliminates the need for high-maintenance joints and complicated transition structures for the crane rails.

A central element of the quay construction is the groundwater management system.Unless specific action is taken, the groundwater would reach a level of 0.30 to 0.50 metres above mean sea level in the infilled sand area behind the sheet piling. As the water level can fall to 4.20 metres below mean sea level at low tide, this could cause excessively high water pressure. A special groundwater management system will there-fore be installed to lower the groundwater level. The water runs through four parallel filter pipes (diameter: 350 millimetres) into a central drainage system.

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In the brackish water area at the mouth of the Weser, bare steel parts suffer from extremely high corrosion. In the tidal area, pitting can amount to up to one millimetreper annum. All steel parts beside the water will therefore be given passive and activecorrosion protection. Passive corrosion protection takes the form of four coats of polyurethane-based anticorrosive paint, which is applied from the top of the quay downto the bottom of the mooring basin. There is also an active cathodic protection system,powered by an external current source.

The new quay will be equipped with all the usual features. Double bollards, each designed to withstand 200 tonnes of tension, will be installed at intervals of approx. 35 metres. Fendering consisting of reinforced concrete fender slabs which will be suspended from steel piles in front of the quay at intervals of around 35 metres. Thesefoam-filled floating fenders are 3.40-metres long and two metres in diameter. The quaywill also have fresh water and firefighting water supply points, electricity and telephoneconnections as well as all the necessary equipment for gantry operation.

Photo ➊ Protection against corrosion: the bearing piles are carefully coated Photo ➋ Drilling and shaping work: the floor of the wave absorber is formed Photo ➌+➍ Working with two concrete pumps: pouring the wave absorber

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Huge quantities of sand from the Weser and Jade Carefully coordinated construction phase concept – Optimum flood protection

Some 10.5 million cubic metres of sand have to be deposited at the CT 4 constructionsite. Hopper dredgers get some of that quantity from the Outer Weser fairway, the rest is obtained from the River Jade and a dredging site located roughly 15 kilometres north-east of the island of Wangerooge. Roughly 20,000 cubic metres are dredgedevery day.

Construction of the quay, backfilling and raising the terrain level are all executed simultaneously. As a general principle, the work proceeds from south to north. Due allowance has to be made for the massive settlement that occurs as a result of the thicklayers of marshy soil. Changes are monitored constantly using special settlement levelgauges, arranged in a grid of 50 by 50 metres. The top layer of approx. 25 centimetreswill be filled with sand obtained from sandpits near Bremerhaven, which will be broughtto the site by truck. This “dry” quarry sand is necessary as a basis for the next step,which involves stabilising the ground with a cement mortar mix.

The terminal extension in the Weser estuary demands a carefully coordinated construction phase concept, as it is vital that the different works do not obstruct eachother. Moreover, time is pressing. Completed sections of the quay are to be put intooperation as soon as possible. The first 350-metre long berth is to be handed over to the Container-Terminal 4 operators at the end of 2006.

On completion of the soil replacement phase, pile driving began in November 2004. The pile driver on the first jack-up platform vibrates the bearing piles, the driver on thesecond one vibrates the batter and intermediate piles. Working in the rhythm of the tides, the workmen immediately connect the batter piles to the sheet pile wall, beforethe area behind the sheet piling is filled in with sand to a level of 2.50 metres above

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mean sea level. Flood banks prevent water from the Weser penetrating the backfilledsections during high tide. The number of workmen and the amount of equipment in usefor driving in the pier slab foundation piles and concreting are adjusted to match thework rate of the jack-up platforms.

The surfaces are given a bituminous base course. Rainwater falling onto this area will be collected in slotted channel drains and run off via gullies. It then flows through stormsewers into a central collection sewer, from where it is carried on to the quay area andthrough a drainage system into the Weser. This drainage system includes slide gateswhich can retain a certain quantity of water.

The design water level for flood protection barriers at the Container-Terminal is 6.30 metres above mean sea level. The quay takes over the function of a dyke as astormflood protection. As the wave absorber already provides the terminal with idealprotection against overtopping waves, a height of 7.50 metres above mean sea level is sufficient for the quay.

The crest of the new enclosing dyke at the north of CT 4 will be raised to a height of8.50 metres above mean sea level. That figures corresponds to the total dyke height inWeddewarden and the region of Land Wursten to the north. The dyke consists of sandand a two-metre thick covering layer of marsh soil.

Imprint

Published by:

bremenports GmbH & Co. KG

Elbinger Platz 1

27570 Bremerhaven, Germany

www.bremenports.de

www.ct-bremerhaven.de

Editor:

Rüdiger Staats

Translation:

Elizabeth Rülander

Photos:

Wolfhard Scheer, Archiv bremenports

Design:

Schendel Design Agentur, Bremerhaven

Produced by:

Schendel Media Service GmbH, Bremerhaven

1st edition (2005)

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Photo ➊ Summer 2004: the waterside construction site takes shape Photo ➋ In action: hopper dredger (front), dredger and barge (back) Photo ➌ ”Rainbow” method: hopper dredgers fill in the pit Photo ➍ In front of Weddewarden: sandy area in the dyke foreland

Heading for the Future: We Construct the Terminal of Tomorrow

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Photo ➊ The birth of a terminal: view of the CT 4 construction sitePhoto ➋ At work in the Weser estuary: dredger ”Geopotes 15”

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