Deepwater Container Terminal Gdańsk: A combined wall of ArcelorMittal sheet piles as quay walls

The main element of the construction of the Deepwater Container Terminal (DCT) Gdańsk in Poland is an artificial peninsula: a rectangular pier with a surface area of 40 ha. A complete geotechnical analysis and various on-site testing allowed for an optimised design and construction based on HZ double profiles as bearing elements. These were realised with AZ filling profiles and HP anchoring piles made of ASTM-A690 steel produced by ArcelorMittal.

Detailed information

DCT Gdańsk - Poland's vital handling centre in the Baltic Sea

The DCT Gdańsk has made Gdańsk an important handling centre in Eastern Europe. Upon completion of the first stage of construction, the terminal had a handling capability of 500 000 TEU* (Twenty-foot Equivalent Unit) containers a year.

In the first year of activity, 2008, the DCT Terminal handled 106 356 TEU containers. According to the project, the terminal’s target handling capability needs to reach 2 million TEU per year.

The DCT contracted building corporation Hochtief to realise the project as the leading contractor. The main element of the construction is an artificial peninsula: a rectangular pier of 800 m x 315 m and a surface area of 40 ha.

The length of the pier was set according to the required length of mooring line and the width, according to the capacity of the stacking yard, of 22 000 TEU containers. The manoeuvring area connects the pier with the seashore where it widens towards the land.

The most forward point of the pier extends 900 m away from the natural shoreline. The solutions and technologies utilised for the construction of the terminal were considered a breakthrough due the extent and degree of complications caused by local conditions. This construction investment introduced new standards. Hochtief used the improved and adapted local condition solutions developed earlier during the construction of the largest European terminal in Bremerhaven, Germany.

Geotechnical research, testing, and preparation work

Design, construction, and maintenance of a pier is undoubtedly a difficult engineering challenge in terms of geotechnics as well as harbour engineering. Before the design was drawn up, a geotechnical study was carried out.

The first stage of research, conducted at the request of the investor, was performed for the needs of the construction design. Forty-one 30m-below-sea-level holes were made. Drilling was performed from drilling boats with the use of standard drilling equipment lowered with the use of a tripod and diesel winch with a percussive-rotatory system in 133 mm and 160 mm diameter casing pipes.

The second stage of geotechnical research of the seabed in the area of the planned pier was conducted at the request of the contractor. The aim was to deliver complete geotechnical data that would enable greater insight and decision-making capabilities that would lead to increased construction optimisation.

The initial proposed solution was not to build the pier in the form of a bulkhead, but rather as single-anchored sheet piling. The degree of compactness was tested at 25 m in 17 different locations with the use of Dynamic Probing Super Heavy (DPSH) testing. Soil cohesion was determined with the use of Standard Penetration Testing (SPT), taking samples from 12 locations. Finally, the degree of the soil’s shear strength in undrained conditions was determined with the use of Field Vane Testing (FVT) in 19 locations.

The findings of the geotechnical research made it possible to establish a clear model of the geological layers. The model showed that an organic soil layer (clay and sludge) between 1 m and 7 m thick lies approximately 12 m directly below the seabed. This layer is characterised by a low resistance to shear pressure and a degree of plasticity of 0.42. Therefore, the initial proposed solution was not feasible as it is only possible in layers with clay sands and loose or medium compact sands.

The optimal solution: An HZ-AZ combined steel sheet pile wall and sand in the pier structure

In the end, an alternative solution was adopted: breakwaters to the north and east made of steel sheet piling, a pier built on load-bearing elements of combined sheet piling, and three rows of piles with a slope of 20:1. The sheet piling for the pier was constructed with HZ 775B-26 double profiles and 28.3 m long AZ25 filling profiles made of ASTM-A690 steel produced by ArcelorMittal. The bearing elements of the piling were anchored after putting in the filling elements with the use of sloping piles made of 26 m long HP 400 x 122 profiles with anchor plates, reducing the risk of damage to the structure caused by wave movement.

An Odin platform was used for driving the piling elements and their anchoring. The filling and anchoring elements were mounted with the use of a pile driver. In the first stage, the driving of the bearing elements was carried out with the use of vibration technology, while a hydraulic hammer was used for the last four metres in order to increase the bearing capacity of the profiles.

When the advanced stages of construction of the pier began, silting began. At first, in order to fill in the area directly behind the piling, a hopper dredger propelled a mix of sand and water in a high arc to the inside of the pier (rainbowing). Next, because of the limited reach of the dredger, pipelines were used to enable the transport of the spoil. About 6000 m3 of sand is transported in one cycle, which corresponds to the freight of 700 trucks. The amount of sand necessary to fill in the pier completely was estimated at 2.22 million m3.

Load requirements

The surface area of the pier will mainly be subject to the containers stored on four levels with a load of 50 kN / m2. Each stack of containers will be handled by a 16-wheel rubber tyred gantry crane with a maximum load of 159 kN / wheel. Trailer tractors with a maximum load of 115 kN / axle will be used for delivering containers to stacking yard. The acceptable subsidence of each pier element caused by any permanent or temporary load was precisely specified in the customer’s technical specifications.

Subsidence monitoring began during construction with the aim to control the construction and verify the design assumptions and solutions. The results of the research and measurements conducted during the construction confirmed the design assumptions and construction solutions.

*TEU is an inexact unit of cargo capacity used to describe the capacity of container ships and container terminals.

Project information

  • Gdańsk
  • Poland
  • 2005 - 2007
  • Architect:
    BPBM Projmors Gdańsk & HOCHTIEF Construction AG
  • Client:
    DCT Gdańsk S.A.
  • Contractor:
    HOCHTIEF Construction AG Infrastructure Polska Sp.j., HOCHTIEF Construction AG Civil Engineering and Marine Works
  • Photographer:
    ©DCT Gdańsk S.A.
  • Text:
    Lechosław Bierawski