Innovation in Infrastructure Aquaspira FAST AND SAFE Aquaspira supplied prefabricated, multi-leg composite steel reinforce tanks to a housing development in Scotland, saving time on site and ensuring long term performance. s part of the concepts with the developer, the infrastructure required civil engineering contractor, Tough to enable a major Construction identified a series of issues new development concerning the physical construction of for Bellway Homes large concrete underground tanks in both at Broxden, on the locations and the inevitable disruption to port manifold. The inlet pipe connects outskirts of Perth, the consulting local residents and traffic. into the upstream end of the first pipe engineersA for the project, Dougal Baillie The contractor had recently utilised only, which effectively converts the first Associates (DBA) were tasked with AquaSpira Composite Steel Reinforced pipe into the primary, combined carrier providing substantial additional storage (CSR) large diameter pipes in place of and storage pipe, with the remaining six capacity within the local Scottish Water conventional concrete pipes on a number pipes functioning as secondary storage sewer network at two separate locations. of housing developments and approached pipes at times of peak discharge. The initial concept designs were based AquaSpira with a view to assessing the A key criterion was to ensure that once on traditional concrete tank structures potential for providing an alternative the project commenced, the risk which, until recently, had been the solution that would minimise deliveries, of delays to the programme were conventional method of design approved plant requirements, time and disruption minimised. A further complication was by the water company. to local residents and traffic. the fact that the site investigation report One of the challenges of the project The contractor was aware of the fact had identified ground water, which meant was that both sites are located in areas that AquaSpira is primary supplier of that tanks with insitu welded joints could with significant constraints, in terms of large diameter pipes and tanks to Scottish not be used. space, shape, access for heavy plant and Water Capital Projects, and assumed that The manifold and pipes on the delivery of materials. The only access to this would assist in the process of gaining AquaSpira system are supplied with one of the sites is via narrow residential approval for adoption with Scottish Water spigot and socket, push fit joints with streets. The other is surrounded on all Development Operations. integral ring-seals, enabling them to be three sides by two active highways, The design proposal for Tank 1 at installed in trenches where groundwater a traffic junction, and an adjacent Darnall consisted of seven parallel runs may be present. Once connected, a watercourse. of 1650mm diameter pipes, connected high performance, watertight joint is On reviewing the initial design at the downstream end by a single seven formed with no requirement for internal 68 NEW CIVIL ENGINEER | JANUARY 2019 IN PARTNERSHIP WITH AQUASPIRA welding in confined spaces, or fitting large Above: Pipes waste water standards and specifications reduces the risk of problems emanating external couplings. safely pushed manager, visited the site when work from concrete chambers constructed To maximise long-term performance home with began to see the tank components on site. The layout is much simpler and and durability, particularly at the innovative jointing first-hand and observe the start of the more efficient too, with thought given at fabricated weld seams, the manifold was frame installation. the design stage towards minimising the manufactured as a single unit from robust, Top right: Robust “This has to be the way forward,” he risk of blockage, and providing complete, stainless steel material. manifold easily said, “utilising high quality, prefabricated but not excessive, access for future Tough Construction project manager lifted into position units, produced off-site in a quality- inspection and maintenance.” Craig Lavery commented: “On arrival Bottom left: controlled factory environment, greatly Work on site for Tank 2 at Cherrybank, at site, the unit was safely offloaded Manifold quickly Broxden is scheduled to start in January and placed into position with a standard set to line and 2019. While still connecting into a single excavator. level A key criterion four port manifold at the downstream “Once in place, we immediately Bottom right: end, each leg of the tank is different in commenced the systematic process of Simple, concise was to ensure length, designed to precisely match the laying the pipes, working away from the layout of new tapered shape of the location. manifold, and progressively backfilling, storage tank that once the project Since completion of the first tank which in turn kept the size of the in January 2018, several have been excavation, and the arisings from the commenced, the designed and successfully installed for excavation to a minimum at any given risk of delays to the similar applications, clearly marking this time during the installation.” as “the way forward” in terms of design This is the first tank of this type to “ optimization, programme reduction and programme were be approved and adopted by Scottish minimising disruption to local residents Water and Martin Faulds, its water and minimise and traffic. JANUARY 2019 | NEW CIVIL ENGINEER 69.