- Case study
- Al Faw Pile Encasement New
- Iraq
Encasing Over 700 Steel Piles, One Tide at a Time, Al Faw Grand Port
Over 700 steel piles on the first quay sit fully exposed between tidal cycles, in a highly aggressive marine environment. Cathodic protection was deemed ineffective above low tide. The original approach, precast concrete sleeves with annulus grouting, was labour intensive, diver dependent and poorly suited to the repetitive nature of the installation. The works needed a method that could be repeated over 700 times within the tidal windows.
Location
Al Faw Grand Port, Iraq
Client
Iraqi Ministry of Transportation
Designer
SENet
System
Marine Pile Encasement Concrete Fabric Formwork
Period
2022 – 2024
Results at a glance
Piles encased
Vertical and raking steel piles on the first 1.75 km quay, all within the tidal limitations of the site.
mm encasement
Reinforced concrete cast insitu against the pile, over a prefabricated rebar cage.
Tide per jacket
Each jacket installed and filled inside a single low tide window, then stripped the next day and reused.
Contents
- Over 700 steel piles on the first 1.75 km quay sit exposed between tides, in an aggressive splash and tidal zone.
- Cathodic protection was ineffective above low tide, so a concrete encasement was selected for the 100 year design life.
- The original precast sleeve and annulus grout approach was labour intensive, diver dependent and did not repeat well.
- Proserve developed a reusable lift-in jacket: a steel frame housing a fabric liner and rebar cage, assembled onshore.
- Each jacket is filled inside one low tide window and the frame is stripped and reused the next day, with no divers.
The constraints
Al Faw Grand Port is a flagship marine infrastructure development on Iraq’s southern Gulf coast, featuring one of the longest quay walls in the Middle East. The port’s first 1.75 km quay includes over 700 vertical and raking steel piles that are fully exposed between tidal cycles, in a highly aggressive marine environment subject to corrosion in the splash and tidal zones.
Conventional cathodic protection was deemed ineffective in this intertidal zone, because the piles spend so long exposed above low tide. A concrete encasement was selected instead as the most durable long-term protection, and the one able to meet the 100 year design life with minimal maintenance.
That decided the material but not the method. The original approach, precast concrete sleeves with annulus grouting, proved operationally inefficient on three counts: it was labour-intensive, it was diver-dependent, and it was poorly suited both to the tidal constraints and to the repetitive nature of an installation that had to happen over 700 times.
The solution
Proserve developed the Lift-In Pile Encasement Jacket System: a modular, reusable solution combining factory-fabricated steel installation frames with grout-tight fabric formwork liners. The steel frame is the tool that is reused. The fabric liner is the form that casts the encasement.
Each pile jacket unit was assembled onshore in three stacked vertical frame segments, housing:
- A fabric formwork liner, to cast the 200 mm thick reinforced concrete encasement.
- A prefabricated rebar cage, to enhance structural integrity.
- Quick-release ties and corner stiffeners, to maintain geometry during handling and casting.
Assembly onshore is what makes the difference. The unit arrives at the pile complete, with the liner, the cage and the stiffeners already inside the frame, so the overwater operation is a lift rather than a construction sequence. The same jacket system is applied to existing piles for structural remediation and protection, set out under marine pile repairs.
Constructability and installation
The cycle is four steps and it repeats, which is the whole point of it. Fabric formwork is used here in the same way it is used for grout bags and sock seals, as a form that adapts to what is already built rather than something the structure has to be adapted to suit.
Assemble onshore
Each pile jacket unit is built up on land from three stacked vertical frame segments, with the liner, the rebar cage and the stiffeners already inside it. Nothing is assembled over water.
Lift into position
The frame is lifted over the pile using mobile cranes. Because the unit is complete when it arrives, positioning is a crane operation rather than a construction operation.
Fill on the low tide
Concrete is tremie-pumped into the liner from the surface during the low tide window. The fabric is grout-tight yet permeable, so water bleed escapes naturally through it while grout washout is prevented, resulting in a low water:cement ratio of about 0.4 and a dense concrete finish.
Strip and reuse the next day
The steel frame is stripped the following day and moved to the next pile. The liner stays with the concrete. That reuse is what turns a one-off method into a production line.
One number is worth pausing on. The water:cement ratio here came out at approximately 0.4, below the figure given as typical for fabric formed concrete generally. It is the bleed that does it: water escapes through the liner during filling, and the concrete left behind is denser than what was pumped in. On a structure specified for 100 years in a chloride environment, that matters.
The other consequence is throughput. Because the jacket is installed and filled within a single tide and the frame is back in service the next morning, daily production is limited only by how many frames are on site. That is a scheduling problem rather than a marine operations problem, which is a much easier thing for a contractor to solve.
Outcome
The Lift-In Jacket System delivered a durable, buildable solution under difficult site constraints. The system minimised time-critical overwater working, significantly increased productivity, and removed the need for high-risk diver activity altogether. Key outcomes:
- Efficient concrete encasement of over 700 piles within the tidal limitations of the site.
- Reuse of formwork across the full installation, maximising resource efficiency.
- Reduced marine risk by eliminating diver-based grouting.
- Uniform, dense encasement with high resistance to corrosion and chloride ingress.
- Enhanced programme certainty and minimised disruption to the parallel quay works.
This was not the only Proserve system at Al Faw. The berth scour protection to the same 1.75 km jetty is a separate scheme, and is covered in the Al Faw berth scour protection case study.
Wider use
Beyond new-build works like Al Faw, Proserve pile jacket systems are applied extensively in structural remediation and protection schemes worldwide:
- Corrosion protection. Particularly suited to tidal and splash zone exposure, where sacrificial anodes or cathodic systems are ineffective.
- Structural repair. Restores and improves the capacity of degraded piles through cast-in-place reinforcement.
- Material compatibility. Applicable to steel, concrete and timber piles, in both tidal and submerged conditions.
- Constrained access. Modular lift-in designs allow retrofitting under existing structures or in confined working zones.
The constrained access case is worth drawing out. Because the lift-in design is modular, it allows retrofitting under existing structures or in confined working zones, which is where conventional formwork runs out of room.
Who did what on this project
Owner of the Al Faw Grand Port development.
Developed the Lift-In Pile Encasement Jacket System: factory-fabricated steel installation frames and grout-tight fabric formwork liners.
Continue
Al Faw Grand Port, berth scour protection
The scour protection to the same 1.75 km jetty: 430,000 m³ of imported rock armour replaced by 26,500 m³ of locally batched concrete.
Read the case study →Piles corroding in the splash zone? Send us the pile and the tide.
Send us the pile type and diameter, the length needing encasement, and your tidal window, and we will come back with an outline: jacket configuration, encasement thickness, and how many frames the programme would need. New build or remedial, the system is the same.
- Pile material, diameter and condition
- Length of the zone needing encasement
- Tidal range and the working window it gives you
- Whether this is new build or remedial, and the design life