Gulf Construction Online - Durrat bridges get Stirling protection

Waterproofing

The treated bridge structure by sunset.

Durrat bridges get Stirling protection

Orbis International has recently completed coating the decks of the bridges connecting the Durrat Al Bahrain using Stirling Lloyd’s Eliminator membrane, indicating the focus on long-term protection that the prestigious island project is striving to achieve.

01 November 2007

A top waterproofing system from a British specialist is now protecting the bridges at the Durrat Al Bahrain resort, which will welcome its first residents early next year.

To ensure easy access between the resort’s islands and with the mainland, the project required the construction of 13 bridges, with a total of 58,000 sq m of bridge decks and service trenches requiring effective long-term protection from corrosion in the harsh marine environment.
With the bridges playing an important role in ensuring easy access between the various islands of the resort, the main contractor for the development – a joint venture between Nass-Murray and Roberts – had to ensure that the waterproofing protecting the bridges would provide a sterling performance.
After a technical and commercial appraisal of the competing systems, the contractor chose the Eliminator, a spray-applied methyl methacrylate (MMA) resin-based system from the UK-based Stirling Lloyd.
The contract to apply the system – which consisted of a primer, 2 mm of Eliminator membrane and a tack coat which would provide a tenacious bond to the asphaltic surfacing on the deck sections – was awarded to Orbis International of Bahrain.
“Once on site, several of the advantages offered by the Eliminator system came to the fore,” says Dave Mulligan, marketing manager for Stirling Lloyd. “The service trenches presented the challenge of upstands and parapets, which would have been a major problem for traditional sheet systems but presented no issues for the liquid, spray-applied Eliminator system.”
“Eliminator cures to form a seamless membrane and its thixotropic nature enables the membrane to follow the profile of any detail and ensure a fully-bonded waterproofing system at all times,” he points out.
Application of the waterproofing through the Bahraini summer with its high levels of humidity could have caused application problems for moisture-sensitive systems, but the high tolerance of MMA resins, which offer the widest weather window of application, meant that application was unaffected and helped Orbis International to keep ahead of the scheduled programme, he adds.
Selection of the Eliminator system also allowed the main contractor to be more flexible with its programme.
Mulligan elaborates: “There is no critical overcoating time with the Eliminator system as the MMA system’s chemistry ensures a full chemical bond between laps, days and even weeks later. This advantage was admirably demonstrated when heavy rainstorms postponed work for three days. Once the storms stopped, the previously-applied membrane and primer were simply blown dry and application recommenced, with no requirement for special treatment at the day joints. This would not have been the case for all polyurethane, polyurea, polyester and epoxy systems for which any delay requires time-consuming re-priming and abrading of the membrane and primer before spraying can begin. This feature gave the Nass-Murray and Roberts JV site staff great flexibility in choosing which area was to be coated next – be it the deck sections or service trenches, aiding contract progression and allowing greater efficiency in scheduling other trades. “These features together with the inherent speed of application of the Eliminator system, based on its ease of application and its rapid cure – which enables the next phase of the work to begin in under an hour – meant Orbis International was able to handover structures months ahead of programme.
“The ease and speed of application of Eliminator together with its ultraviolet (UV) resistance, excellent ageing properties and unparalleled track record of success in protecting major structures around the globe meant that not only is the vision of the Durrat Al Bahrain closer to reality than would otherwise be the case, but that the investment in the structures on this prestigious project will be protected for the duration of their design life,” he concludes.
Durrat Al Bahrain – named after the most perfect pearl – has been designed to be a model city resort and provide a modern, opulent lifestyle. Located on the south coast of Bahrain, across a stretch of reclaimed desert and sea, the resort will be just 35 minutes from Manama on the proposed new, dual carriage highway.
Jointly owned by the Bahrain Government and Kuwait Finance House (Bahrain), Durrat Al Bahrain incorporates both high-quality materials and modern design principles and aims to set a new standard for urban development in the kingdom.
The stunning design has been provided by W S Atkins, the internationally renowned engineering design and consultancy firm. The project is the vision of Tom Wright, W S Atkins’ director of architecture who is the designer of other globally recognised projects such as the Burj Al Arab hotel in Dubai.
The design of the 20 sq km seaside city resort incorporates 13 different islands with more than 2,000 villas, 3,000 apartments, luxury hotels, restaurants, promenades, shopping centres, spas as well as a planned marina and golf course among its many sports facilities. It is envisaged the luxury development will evolve according to the city’s needs and wants and become the country’s largest city resort and a landmark project that will position Bahrain as a premier tourist destination.