Robert Jansen
Technical Sales Manager
Retaining walls retain soil and water along waterways, harbours, and urban quays. For higher loads and when replacing retaining walls, reliable anchoring is decisive for the stability, deformation, and lifespan of quay structures.
Quay walls are permanent earth-retaining structures along water. They resist the soil and water pressure behind the wall and accommodate loads from crane tracks, storage, traffic, and moored vessels. The wall typically consists of a sheet pile wall, combi-wall, or concrete wall, depending on depth, load, and service life requirements.
A quay wall structure functions by controlled dissipation of horizontal and vertical forces. The wall absorbs the bending moment, while the base provides fixity in the subsoil. For greater retaining heights or stricter deformation requirements, a free-standing wall is insufficient.
In that case, the wall is anchored. An anchoring system transfers the horizontal tensile forces to a stable ground layer behind the slip plane. Strand anchors are an efficient solution for this: high capacity, slim profile, and suitable for both new construction and the replacement of quay walls under restricted working space. The anchor consists of an anchor head, a free length and an anchored length, which cooperates with the subsoil through grouting.
Other solutions and applications
In the design and execution of quay walls, several factors collectively determine the functioning of the construction. The interaction between the wall, anchor, and subsoil is decisive for both failure safety and the serviceability limit state:
An anchored quay wall is constructed from a retaining wall, a waling, and an anchoring system that transfers forces to the subsoil. The wall is usually a diaphragm wall or combi-wall of tubular piles with intermediate sheeting. The wall absorbs soil pressure, water pressure, and overburden loads and transfers these through bending and fixity at the base.
At or just below ground level lies a purlin or distribution beam. This distributes the concentrated anchor forces evenly over the wall and prevents local deformations at the anchor head. The strand anchor consists of an anchor head with wedges, a free length in a duct, and an anchored length which transfers force to the ground via grouting. The tensile force from the wall is thus transferred to a stable soil layer behind the active slip surface.
The anchor, purlin, anchor head, and anchorage length work as one system. When replacing quay walls, their collaboration is recalculated: new loads, old ground structure, and existing surroundings determine the final design.
Vibration control, phasing, and deformation management are particularly critical when replacing quay walls in urban areas. Early coordination between the structural engineer, contractor, and supplier prevents surprises during construction and ensures the desired service life of the quay structure.
Every situation is different. In a consultation, we will clearly outline your project and possibilities. You will immediately know where you stand.
Robert Jansen
Technical Sales Manager
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A quay wall is a permanent earth-retaining structure along water. The wall retains earth and water and supports loads from crane tracks, storage, traffic, and berthing ships.
The wall is usually constructed as a sheet pile wall, combi wall or concrete wall, depending on depth and load.
A quay wall is anchored when the wall cannot independently withstand the imposed loads, or when deformations need to be limited.
This applies to larger overturning heights, high superimposed loads, limited permissible deformation, and to sensitive adjacent properties along the quay.
Tension anchors offer a high tensile capacity in a slim profile. This allows for stiffer and more efficient quay wall designs, with better control of deformations.
Ook are they applicable in limited workspaces, which is a significant advantage, particularly when replacing quay walls in urban areas.
Many quays border steel sheet piles, pipelines, or installations with cathodic protection. A metallic path via the anchor can cause unwanted corrosion or current leakage. An electrically insulated strand anchor (PL3) interrupts this path. Deepro is currently the only company in Europe to supply this with ETA certification.
Upon replacement, the existing quay wall is completely or partially removed and a new wall with anchoring is installed.
When strengthening, the existing wall remains and the construction is supplemented with, for example, extra anchors, a new purlin or an additional wall. The choice depends on the condition of the existing construction, lifespan requirements and environmental requirements.
For permanent quay walls, anchors in PL2 or PL3 are used with a design lifespan of at least 100 years if correctly executed.
For temporary phases during quay replacement, PL0/PL1 anchors are common. The chosen corrosion protection class depends on the environment (fresh, brackish, salt), load and desired functional lifespan.
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