Metal culverts are conduits that are placed underneath the road surface for drainage of the ditches located at the end of back slopes. These culverts are extremely important for the integrity of road structures. Without the metal culverts in place underneath roads with crowned drainage systems at specific intervals, the water flow in the ditch may build up to a critical level, which can cause sinkholes and road damage.
Though it is possible to construct the relief culvert from many types of materials, the corrugated-metal type provides durability, low maintenance, easy installation, and longevity. These factors are all crucial to keep the cost of road maintenance low. The metal pipes we supply are either arches or circular. Both the arch and circular types are very strong and able to carry heavy loads because of the strength associated with these types of designs. Add to this the corrugated surface of the metal and you have very strongly integral structures. The corrugation adds a lot of strength; essential when heavy earth loads must be carried.
Untreated metal corrodes, but when galvanised steel is used, the metal is protected against corrosion since the zinc coating protects the underlying surface against the effects of exposure to oxygen and moisture. Steel culverts have lifespan of 25 years or more. With the structures premanufactured and ready for installation, you can minimise the time it takes to install the culverts. There is no need for special assembly at the place of installation. As such, you save time and this means saving money on labour costs. Longer stretches of road can be prepared in shorter periods, helping you to complete road construction projects faster. This means a healthy bottom line and more time to spend on other parts of road construction projects.
Steel culverts are well suited for areas prone to extremely low temperatures where freezing is likely to occur, such as in the Western Cape during the cold winter months. The steel does not fracture or lose integrity when exposed to low temperatures. Metal relief culverts are used in applications ranging from drainage in erodible soils and the provision of drainage at ditches next to roads to transportation of drainage collected at the toe side of fills to the other sections. Such culverts are suited for use at steep road grades, at the low points of vertical curves, at the fill transitions, or when drainage is needed for a long time, such as more than ten years.