Box Culvert Applications
Precast concrete box culverts provide the ideal solution to a wide range of civil engineering and construction applications. Their traditional use is for diverting watercourses. Available in a wide variety of standard sizes, the versatility of these structures sees them increasingly used for attenuation tanks, pedestrian subways, access shafts, service tunnels, sea outfalls, road crossings and a variety of other applications. Where strength, durability and economy are of paramount importance.
Members of the British Precast Drainage Association - comprising all the leading manufacturers of box culverts in the UK - offer the capability to design and manufacture structures to meet specific application requirements and loading conditions. The British Precast Drainage Association produces a standard specification which covers materials, manufacture, tolerances, external loading, design and detailing standards. The box culvert specification also provides a check list of information required from the specifier and provides for the issue of a compliance certificate. Box culverts which are to carry highway or railway loading are designed to current standards and specification as stipulated by the client.
Proven strength and performance characteristics means long service life.
Unlike structure manufactured from alternative materials, such as steel, precast concrete culverts do not require additional treatments to prolong service life or improve performance. They do not rust and the smooth internal finish of the concrete ensures optimum flow of water.
Precast culverts meet the current design-life requirements for buried structures. This ability to provide prolonged service life with minimum maintenance makes box culverts the most economic means of diverting watercourses and providing underground access and service shafts.
Speed of construction and accuracy profile.
Culverting Watercourses and Channels
This is one of the most common uses of box culverts enabling development of land which is crossed by watercourses. It offers economy combined with the optimum flow capacity covering low gradients and headroom and/or width restrictions. Lengths in excess of 1000 metres have been culverted and where necessary skewed units can allow for changes in direction. Openings for access and pipe entry can be incorporated during manufacture and smaller diameter holes can core drilled during installation.
Channels can be provided with or without removable lids thus enabling a wide range of applications from open water course diversion, to service ducts for pipes and cables.
Single or multiple runs of box culverts provide the most economical in-line or offline storage of storm water. These can be located under car parks, grassed areas or under roads following the line of the carriageway. In this instance culverts can be supplied complete with end walls, access and pipe entry openings and are designed to carry the traffic loads or any other surcharge determined by the location.
Rectangular box sections laid side by side, with a nominal gap to allow for relative movement, provide the largest flow capacity in the minimum space.
Road Crossings and Subways
This is another common use of box culverts which offers a cost effective solution and a quick means of construction thus minimising road closure and disruption. Sections are provided with suitable headroom for use as pedestrian subways. Underpasses for cars and light commercial vehicles can be accommodated with larger units. Provision can be made for lighting, incorporation of special finishes, post tensioning if required.
Box culverts can be designed for as little as 200mm cover and, where necessary, for no side pressure relief from the ground. As such they are a perfect replacement for standard pipes maximising the available flow area.
Service and Escape Tunnels and Portals
The inherent fire protection of concrete provides an ideal solution for rapid and safe underground escape from industrial and commercial premises, car parks, shopping centres and sports arenas. Box culverts also provide an ideal solution for accommodating and maintaining underground services.
Other Applications (e.g. shafts)
Specially designed box culverts with increased cover to reinforcement and effective crack control provide the durability to resist the most extreme conditions and are ideal for this type of application. Stacked vertical box culvert access shafts can be constructed to provide access to deep utilities for the housing and servicing of ancillary valves and pipework.