In June 2021, Eurotunnel awarded Metrail a framework contract to undertake the replacement of mechanical expansion joints at the UK terminal. This ongoing project entails the removal of old and damaged joints, conducting essential concrete repairs, and installing Permatrack H joints. The scope of the contract requires the replacement of over 800 linear metres of joints within the span of five years. This significant undertaking is crucial to maintain the structural integrity and smooth operation of the shuttle service at the terminal.
The challenge
The Channel Tunnel, connecting the United Kingdom and France since May 1994, facilitates high-speed trains linking London to Paris and other European destinations. Additionally, roll-on roll-off shuttle services transport freight and passenger vehicles through the tunnel. Eurotunnel operates this shuttle service and is responsible for all associated infrastructure.
At the UK terminal, the elevated decks, ramps, and platforms that support the shuttle service are complex structures, enduring heavy traffic for nearly 30 years, particularly from freight traffic. Ongoing maintenance is vital to ensure the integrity of the shuttle service, with Metrail Construction playing a key role in this maintenance programme.
Facts & Figures
When?
Five-year contract period; work started in 2021
Where?
800 linear metres of joints
How?
Replacing old and damaged joints
Technology
IKO Permatrack H: A heavy duty joint that is a structurally enhanced movement joint
Programme
The terminal has to remain operational at all times and planning is key to minimise disruption and ensure the work is carried out in a timely manner whilst ensuring safety and quality standards are maintained at the highest level. The replacement of some joints requires the platforms, where vehicles access the shuttle, to be closed. Careful planning and extended shifts are required in these locations.
Technology: Jointing System
As a specialist in the sector Metrail Construction has extensive experience in the installation and replacement of bridge deck expansion joints and is one of a limited number of companies approved by IKO Permatrack to instal their bridge expansion joint system.
IKO provide Metrail with product and technical support as required.
The IKO Permatrack H heavy duty joint is a structurally enhanced movement joint ideal for repairing and replacing damaged joints and able to accommodate the movement inherent in bridges and decks.
It can be installed to any depth or width and any localised surface deterioration can be taken into account. The mastic asphalt used is a high modulus material that uses a binder of SBS modified bitumen and Trinidad Lake Asphalt giving low temperature flexibility and high temperature stabilities required for heavily trafficked roads.
Execution
The methodology for the removal and replacement of the old joints with IKO Permatrack joints is described in detail in the contract documentation and the experienced Metrail team ensure that this procedure is carefully followed to ensure high standards of workmanship and quality.
In summary, the old joint is planed out to the specified width. Old plates are removed and both the trench and air gap are cleaned so as to be free of all dirt and debris. Any concrete repairs are then carried out using specialist repair material.
IKO PermaFLASH D300 is used to plug the airgap. Primer is then applied to all the trench surfaces.
A first layer of molten PSB, a highly flexible material used for tanking the trench, is then applied to the base of the trench and a galvanised steel plate placed in the trench.
The trench can then be fully tanked out and a drainage channel and rodding box installed.
The next step is to install the actual expansion material, known as PSB Strips, which provide the majority of the movement for the expansion joint. These strips are applied to the vertical faces of the trench and a further coat of PSB applied.
The trench is brought up to the same level as the rebate so that steel side bars can be installed in the rebate. The joint can then be trowelled level and scattered stones rolled into the surface until satisfactory embedment is achieved.
The steel bars are removed and the resulting grooves filled with PSB.
The joint has to be allowed to cool before opening to traffic.
Conclusion
Metrail’s aim is always to deliver high quality work safely and on time and this is certainly the case at the Eurotunnel UK terminal.
The Civil Engineering Department at the at the UK terminal has commented that they are pleased with the progress being made by Metrail.
The IKO Permatrack joint is one of a range of joints that the Metrail team is trained and licenced to instal.
The award of a number contracts to Metrail in 2021 under National Highways Scheme Delivery Framework means that the company will be installing a range of joints including the IKO Permatrack joint over many years.
