West Calder based civil engineering specialist Mulholland Contracts are undertaking the complete groundworks package for the entire Cammo development, including bulk earthworks, roads and sewers infrastructure and plot works. This also includes installation of the precast attenuation tank, which consists of three main culvert runs with water entering via three 300mm pipe entry points at one end. Each run is made up of 34 individual box culvert sections measuring 4800mm wide x 1000mm high x 1660mm long. Each section has a dry weather flow channel cast into the base which then forms a continuous channel along the length of each culvert run.
To ensure the optimum performance of the box culvert tank, the engineering detail was sought in early collaboration with the FP McCann technical and design team at Weston Underwood. Other attenuation systems were considered, but the robustness and long life performance of this precast system were key determining factors.
The total length of the tank is some 57 metres and has six 675mm square access points cast into adjacent end sections for maintenance purposes. The box culvert sections have been manufactured at FP McCann’s Byley factory in Cheshire and delivered to site over a two week period. A specialist crane was utilised by the Mulholland team to unload the delivery vehicles and carefully position each box section. Once in place and prior to the jointing of each unit, a bitumen based rubber sealing strip was applied to the sloping face of each socket joint.
Commenting on the culvert installation, Kevin Cole Project Manager for Mulholland Contracts says, “Precast concrete box culvert sections have provided the ideal engineering solution to construct this offline attenuation tank. The offsite quality assured manufactured precast concrete products together with their long-life, low maintenance benefits, gives us peace of mind that we have put a very robust foul water management system in place. The units were simply and quickly installed demonstrating the flexibility that precast concrete box culvert sections can offer in such civil engineering projects.”
Also commenting, Pamela Scott Branch Manager at PDM Broxburn said, “PDM are delighted to be involved in this high profile job, working in partnership with FP McCann and Mulholland Contracts to supply the largest culvert order in Scotland which was delivered to site over the course of just 11 days; we continue working together to pursue future projects.”