Groundworks contractor: Strandhill
Type of works: installation of ACO Qmax® drainage system in vehicle yard.
ACO Qmax®, ACOs breakthrough high capacity flow and attenuation linear drainage system, has just had its first installation commissioned in the UK.
Used to manage surface run-off in the vehicle yard at a new strategic distribution warehouse for retailer, Matalan, the site showcases the many benefits the system delivers for designers, contractors and operators. Matalan is the rising star of UK retail. Pioneering out-of-town, low-cost shopping techniques that mirror those developed in the USA, the company has grown rapidly since its launch in 1985. Today, it is the countrys fifth largest fashion retailer with over 180 stores and a turnover exceeding £1billion.
As part of a £25million expansion programme, Matalan has transformed a disused plastics factory in Corby into a strategic distribution centre that will serve its new stores in the south of England. Each of the centres two trailer handling areas a dock-levelling area and a high-bay warehouse/trailer storage yard has had a single straight run of ACO Qmax® installed to manage the drainage of surface run-off and to control the discharge to the main sewer serving the site.
Originally due for commission in late 2004, the project was completed ahead of schedule, becoming fully operational in the late summer. Early completion was due, in part, to the ease of installing the ACO Qmax® system. A total of 358m of Qmax 900 has been used across the two runs - one 222m, the second 136m - with both discharging separately, via petroleum separators, into an existing main drain outside the site perimeter. The shorter 136m run drains an area of approximately 10,500m2. As this is a straight
refurbishment of the sites original dock-levelling yard, with no increase in drained surface area, no planning consent was required to discharge surface run-off into the main drain.
The longer run serves a new area of hardstanding adjacent to the high-bay warehouse which was formerly derelict land. Totalling 13,300m2, it is used for trailer storage and includes a truck refuelling island. Run-off from the island is isolated from that of the main area by a separate installation of 60m of ACO RoadDrain.
At the design rainfall for the site 50 mm/hr the outflow from the new yard would be 185 l/s. However, planning consent restricted the flow to main drain to just 17 l/s. ACOs in-house design team were able to achieve the desired discharge by combining the high storage capacity of the ACO Qmax® run with the energy release provided by a single vortex flow controller or HydroBrake installed between the ACO Qmax® outlet and the main drain connection.
Design of the hardstanding slabwork in both areas has benefited significantly from ACO Qmaxs unique pavement beam feature, which permits the total integrity of the surrounding reinforcement bars, and the channels inherent high load-bearing capacity up to load class F900 with reinforcement of the concrete surround. However, no additional reinforcement was necessary for the channel to support a 20 tonne pneumatic wheel load (typical value for distribution centre applications), and the consulting engineer, BurksGreen, was able to design a single slab detail for the entire site, greatly simplifying the groundworkers task.
Delivered to site in standard 2m lengths that weigh only 58kg, the groundworks contractor, Strandhill, found that a three man gang was capable of installing up to 100m of ACO Qmax® channel in a single day, without any disruption to the ongoing construction of the surrounding slabwork. We found ACO Qmax® really easy to install compared with other more cumbersome high capacity channels as fast as it arrived on site, it went into the ground, says Strandhill Director, Pat Gallagher. Being so lightweight, we could simply drop in sections as the trench was excavated and seal it straight away using the two locking bolts that sit each side of the channel section stopping any dirt ingress. We became familiar with the product very quickly it needs few specialist tools and we saved a lot of time getting it in the ground.
Cleaning and routine maintenance for each run is carried out via a simple hatchway directly above the main channel. Each allows access for high-pressure jet washers and visual inspection, if required. Access to the HydroBrake too is via a manhole on the site boundary. We are tremendously pleased with the initial outcomes of this first installation, comments Peter Ridgway, Market Development Manager at ACO UK.
Overwhelmingly positive feedback from both the design engineers and site have only served to reinforce the complete faith that we have had in ACO Qmax® right from the early stages of its conception. The ease with which the groundworking teams took to installing the channel was remarkable and we are all confident that, operationally, the system will prove equally impressive.