Yas Island Southern Crossing, UAE
Integritank overcomes tough environmental challenges on the Yas Island Southern Crossing
Yas Island, home of Abu Dhabi’s Formula 1 ‘Yas Marina’ circuit, is a luxurious development with decadent shopping malls, championship gold courses, marinas, theme parks and spectacular hotels that is within easy reach of the rest of the Emirate.
The high quality finish throughout the project lays testament to the client, Aldar Properties PJSC.
Even on unseen elements, such as the infrastructure, they have endeavoured to utilise the highest quality and most suitable materials. An example of this is the application of Stirling Lloyd’s advanced waterproofing membrane Integritank to protect the Southern Crossing Tunnel linking Al Raha Beach to the Yas Marina Circuit.
Aldar Properties Pjsc
- Integritank (T) - Yas Island Southern Crossing
Having been used on tunnelling projects throughout the world Integritank was chosen for use on the Yas Island tunnel for the benefits it could offer and its track record of unparalleled success in protecting both cut-and-cover and immersed tube tunnels. The excellent reputation of Stirling Lloyd’s Authorised Contractor, ASTEL, also impressed. To demonstrate the product’s capabilities Stirling Lloyd took representatives of Aldar and TAISEI Corporation to visit another prestigious project, the New Doha International Airport in Qatar, where Stirling Lloyd were waterproofing the various tunnels on the project. During this site visit they were able to see Integritank being applied and backfill being placed directly against the cured membrane, proving its robustness. It also highlighted Integritank’s ability to be applied in hot, windy conditions surrounded by dust and sand without causing detriment to the product’s performance.
With a construction schedule of thirteen months – to be ready for the inaugral 2009 Formula 1 Grand Prix, offering flexibility within this rigid time frame was key. Integritank can be over coated after any interval, with no critical over coating time that affects some resins and so application could take place on one section, but then move to another to suit other elements of the build, aiding contract progression. This is due to the advanced based resin used in the system, which produces a strong bond both to the substrate and to itself, even when applied in stages, with no compromise in quality. The system was spray applied with rapid application rates being achieved, which combined with its rapid cure enabled fast progress in line with the tight programme schedule.
Application Part 1.
Another potential issue for the project’s success was Abu Dhabi’s climate. The hot and humid weather can cause problems for installation of other liquid applied systems. However, Stirling Lloyd’s advanced resins are extremely tolerant of climatic conditions and this enabled Integritank to be applied throughout the high humidity and high temperatures, in excess of 40°C, experienced during the construction period.
In total, approximately 49,000m² of the Integritank system was used on the 1.2km long, 40m wide tunnel. The unique on-site quality assurance programme synonymous with the Integritank system began before application even started. Tensile adhesion tests were carried out on each section of the tunnel to assess the bond strengths the system would achieve. The tests confirmed the values were up to 3MPa, well in excess of the 0.7MPa specified, with the eventual mode failure being found in the concrete itself.
Application Part 2.
On completion of the adhesion test, the concrete substrate was primed with Stirling Lloyd’s PA1 primer. This enhances the adhesion of the subsequent membrane as well as preventing any outgassing, from the new concrete. Once the primer cured, in well under an hour in the temperatures experienced on the project, the first coat of Integritank was then spray applied. Once this had cured, again in well under an hour, the second coat of the Integritank system was spray applied. Each coat is pigmented in contrasting colours, the first coat yellow, the second grey, so that the sprayer can visually check that sufficient material has been applied. This is backed up by constant wet film dipping that helps ensure the required thickness of 1mm for each coat has been applied.
The completed system gives a seamless finish, with no potential weak joints for water penetration, even at the complex detailing, corners and overhead applications found on the project, which would have been the undoing of other systems. Integritank’s thixotropic nature enables it to simply follow the contours of the substrate as well as being applied overhead. When the application of the membrane to a particular section has been completed it was electrically tested for integrity; a method which can identify any faults in a system as small as a pinhole, which if any were found, could then be made good. This test ensures that 100% effective protection has been provided by the Integritank system.
When the tunnel was complete the cofferdam keeping water out from the construction bay was deconstructed and the Southern Crossing Tunnel was submerged with a 25m head of water at the deepest point. The Integritank membrane is left exposed and subject to significant pressure. The strong bond between the membrane and the tunnel ensures this is resisted.
The Integritank system provides excellent chemical resistance and so is not effected by the seawater and chemicals present in the waters surrounding the tunnel. These features are vital, any failure of waterproofing would be extremely difficult to repair. By choosing to use the Integritank waterproofing system, Aldar Properties PJSC can have full long-term confidence in the long-term protection of the tunnel.