Application: Seals to Marine Piles
Location: Dover, UK
Contractor: Volker Stevin
Year: 2017
Project Purpose
The redevelopment of the Dover Western Docks in 2017 involved extensive marine construction works, including the installation of new quay structures, piled foundations, and pre-cast elements. A key challenge was ensuring effective sealing and load transfer between structural components where construction tolerances were large and access was limited.
Concrete Mattress Technology: Expanding Grout Socks
To address this, Proserve’s Expanding Grout Socks were deployed as a tailored, formwork-based solution to create grouted seals, bearings, and shear keys between precast elements and adjacent marine structures. The system leverages the deformability and tensile integrity of woven grout-tight fabrics, enabling compact delivery and reliable performance in confined or complex geometries.
Design Principles and Fabrication
Grout Socks are pre-manufactured in a condensed configuration, formed from high-strength permeable fabric and supplied as pre-shaped units (e.g. straight, ring, or U-shaped profiles). At Dover, this allowed units to be pre-installed onto elements off the critical path—typically during laydown or pre-assembly—reducing interference with subsequent marine operations. Their compact state ensured protection from mechanical damage and weathering prior to activation.
Installation and Filling Process
Once installed and aligned between structural interfaces, the socks were filled using a controlled grout injection process. As grout pressure increased, the sock expanded, rupturing its condensing sleeve and conforming intimately to the surrounding void. This created a custom-fit seal or load-transfer element. The process provided consistent bearing surfaces, improved shear resistance, and ensured continuity across uneven or non-parallel surfaces—challenges common in marine and tidal construction environments.
Technical Advantages
- Tolerant to Misalignment: The flexible fabric accommodates construction tolerances without requiring precise adjustments or bespoke rigid components.
- Compact and Pre-Installable: Condensed form enables early installation, protected from damage, and well-suited to congested working environments.
- Seals, Bearings & Shear Keys: Versatile application for both sealing water ingress and transferring structural loads, reducing dependency on follow-up concrete pours or mechanical fixings.
- Fabric Formwork Benefits: Reflecting the findings in Fabric Formwork Systems Used in Marine Construction (Hawkswood), the system showcases how flexible formwork can produce complex shapes economically, using simple pumping techniques and on-site materials.
- Marine-Ready Solution: Proven in tidal zones, including the Dover Western Docks, where difficult access, time constraints, and water management made traditional sealing or bearing systems impractical.
Project Outcome
The use of Expanding Grout Socks at the Dover Western Docks facilitated effective sealing and load transfer between multiple structural elements within tight marine construction windows. The approach contributed to reduced installation risk, improved tolerance management, and a clean interface between prefabricated and in situ works.
