Lusail Tunnel, Qatar
Integritank system ensures waterproofing success on new Qatar Cut & Cover Tunnel
Opening in Spring 2017, the new Lusail CP07-C-1-A Commercial Boulevard, Road A3 Troughs, Underpass and Tunnel project will connect the recently established Lusail City to the heart of Doha in Qatar. Forming part of a $30bn integrated transportation system, the Lusail Tunnel will ensure easy access to the new Lusail City Development and will be a vital transport link for the planned 2022 FIFA World Cup games.
The overall Lusail City Development located 15km north of Doha covers a 38km2 site, which includes 25,000 residential units, housing 175,000 people, all of whom will benefit from the Lusail Tunnel project. The Development will generate significant economic diversification as it is set to strengthen Qatar’s tourism sector.
The construction of this new underground infrastructure faced challenging ground conditions and fast track construction programmes due to an aggressive and high water table. The tunnel – and troughs to be constructed from Spring 2017 – will carry both road traffic and light rail.
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- Lusail Tunnel, Qatar
Following an initial project review of waterproofing performance to-date by the Client LREDC, they consulted Stirling Lloyd on best practice and how to ensure watertight protection.
Following a number of projects where un-bonded waterproofing systems had leaked on other Lusail sites, LREDC was focused on pushing the boundaries and performance of waterproofing to set new standards on their projects.
In particular, it was important that the quality and effectiveness was improved, as well as the speed of installation of waterproofing systems. Using a best-in-class approach was necessary to protect these concrete structures, which are located below an aggressive and high water table.
Following the consultation, Stirling Lloyd’s Integritank was specifically requested by LREDC as it could meet these strict requirements and provide a watertight structure. Integritank was to be part of a fully bonded offering, including the PVC T-Lock system – a keyed pre-formed sheet membrane for the waterproofing of structural base slabs - a product that has been successfully used on immersed tube tunnels, metro stations and cut-and-cover below-ground structures for the past 20 years.
Past tunnel projects within Gulf Cooperation Council countries such as the UAE, including the Yas tunnel and Bainuna Street, further proved Stirling Lloyd’s capabilities to meet the specialist needs of underground waterproofing, working together with experienced authorised contractor, Intertectra Qatar.
The ease, speed and effectiveness of Integritank’s fully bonded seamless waterproofing system offered the clients the quality and future proofed solution they were looking for, together with the peace of mind required when protecting their investment in the region’s below ground infrastructure.
To meet tight deadlines and the challenging on-site conditions, speed and ease of application were key for the project. The fact that Integritank can be sprayed to verticals and up to 60 metres from the mixing head meant that, unlike with sheet systems, no scaffolding was required when applying to the tunnel walls, greatly reducing the time required for the application and removing an unnecessary cost.
In addition, the membranes puncture resistance and durability meant no additional protection boards or screeds were required – again saving time and money.
Close coordination between the designers, supervision consultants and authorised contractor Intertectra Qatar, as well as Stirling Lloyd’s technical input and on-site technical presence, ensured that quality assurance remained front of mind.
Adhesion pull-off tests confirmed the strong bond achieved by the Integritank system, removing the threat of numerous leaks through water tracking. Watertightness and puncture resistance testing before backfilling also served to further reassure all parties involved of the effectiveness of the system. The same tests conducted after backfilling confirmed that the system had performed as expected and fulfilled its potential on-site.
James Hopper, regional sales manager – Middle East, Stirling Lloyd, comments: “Faced with challenging ground conditions and a fast track construction programme, the ease, speed and effectiveness of the Integritank fully bonded, seamless waterproofing system was integral to the success of the project.
“For the client, it had also been important to have the reassurance of the system’s efficiency before beginning work. As Stirling Lloyd had already completed several other similar projects in the area, it was a natural decision to choose Integritank when further protecting the investment in the region’s below ground infrastructure.
The ease and speed of application, as well as the strong bond of the Integritank system meant the Lusail Tunnel was effectively and efficiently waterproofed, quickly and easily, helping to save costs and programme time – providing considerable savings especially when compared to the alternate un-bonded sheet systems that had also been considered.