The new Horse Tunnel from the stables through to the mounting yard at Melbourne’s Flemington Racecourse remained ‘on track’ for a totally waterproofed finish, thanks to a range of state-of-the-art waterproofing solutions from BASF Construction Chemicals. Part of a massive $13 million redevelopment of Flemington’s famous ‘Birdcage’ area, the new tunnel has been designed to improve safety at the track by diverting horses away from crowds as they make their way from the stalls to the mounting yard before each race.
As is often the case with tunnelling and underground construction projects, the Flemington Horse Tunnel presented a number of significant design, engineering and construction challenges. Together with the extremely tight construction time-frame (the redevelopment had to be completed in time for the Makybe Stakes in early September), the combination of location, geology and hydrology presented a major waterproofing challenge for the VRC. Gemma Nolan, Business Development Manager with Austress Freyssinet Pty Ltd, explained:
“The Flemington Racecourse is located immediately adjacent to the Maribyrnong River. This, combined with the fact that the tunnel is being constructed below the water table in Coode Island Silt, means that the performance of the waterproofing methods and materials used are critical factors in the success of the project.”
“The VRC wanted to be sure that the finished tunnel was totally waterproofed and didn’t leak, and what’s more, that it would remain that way for the long-term.”
“With that in mind, we worked with the VRC, architects the Buchan Group, engineersGrogan Richards, and the builder Construction Engineering, to develop a design concept and specification for the tunnel waterproofing,” she said.
“After making a detailed assessment of the project requirements, we recommended using a range of waterproofoing solutions from BASF Construction Chemicals, including the Masterflex ® 900 reinjectable hose system and the Coniroof ® 2113 waterproofing membrane system,” Gemma Nolan added.
Measuring some 193 metres from ramp to ramp, the project incorporates 80 metres of ‘cut and cover’ tunnel with internal dimensions of 3.5m x 3.6m. Following the excavation works and the establishment of a ‘blinding slab’, Bentonite matting was laid down prior to the tunnel’s floor slab being poured. This was then followed by the construction of the poured-insitu walls and roof sections. For maximum waterproofing effectiveness, all joints - both along and between the floor, wall and roof sections – were fitted with the Masterflex® 900 Injection System reinjectable hose system from BASF Construction Chemicals.
Specifically designed for ‘jointed’ concrete structures which are subjected to hydrostatic pressure on one or both faces of the structure, Masterflex® 900 hose is installed along the joints and then injected with an appropriate injection material – causing it to swell and seal any voids along the joint. Importantly, Masterflex® 900 is able to be injected at any time, thereby allowing it to cater for slight movement and/or expansion of joints which can occur over time. For the Flemington Horse Tunnel project, the Masterflex® 900 hose has been installed as a ‘secondary’ waterproofing solution, which can be injected with Masterflex® 801 - highly flexible methacrylate crack injection resin - if need be.
The second stage of the tunnel waterproofing process incorporated an application of Coniroof® 2113 to the external surfaces of the tunnel roof and walls. A member of the state-of-the-art Conipur® family of waterproofing membrane systems, Coniroof® 2113 is a waterproof membrane system comprising a primer coat followed by a layer of Conipur M810, a highly elastic polyurethane resin-based crack-bridging membrane. Suitable for use on vertical and horizontal concrete substrates (including inverted roofs), the Coniroof® 2113 system delivers the ideal combination of outstanding longterm durability, high elasticity and extremely fast curing time.
“The combination of the Masterflex® 900 and the Coniroof® 2113 system has provided us with the ideal waterproofing solution for the Flemington Horse Tunnel,” Gemma Nolan said. “The versatility and flexibility of the Masterflex® 900 reinjectable hose, together with the toughness and flexibility of the Coniroof® 2113 membrane system, have combined to deliver a highly-effective long-term total waterproofing solution,” she concluded.
About the Construction Chemicals division
BASF’s Construction Chemicals division is the leading supplier of chemical systems and formulations for the construction industry. Continuous innovation and tailor-made solutions ensure its customers are more successful. Its Admixture Systems business unit specifically helps customers in the ready-mix, precast and manufactured concrete and underground construction industries. The Construction Systems unit offers a wide range of products for sports and industrial flooring, external renders and wall insulation, expansion joints, wood preservatives as well as specialist repair mortars, tile adhesives and waterproofing membranes. The division operates production sites and sales centers in more than 50 countries and achieved sales of €2.2 million with approximately 7,500 employees in 2006.
BASF is the world’s leading chemical company: The Chemical Company. Its portfolio ranges from chemicals, plastics, performance products, agricultural products and fine chemicals to crude oil and natural gas. As a reliable partner to virtually all industries, BASF’s high-value products and intelligent system solutions help its customers to be more successful. BASF develops new technologies and uses them to meet the challenges of the future and open up additional market opportunities. It combines economic success with environmental protection and social responsibility, thus contributing to a better future. BASF has approximately 95,000 employees and posted sales of €52.6 billion (approximately $66.1 billion) in 2006. Further information on BASF is available on the Internet at www.basf.com