Blocked or collapsed culverts can cause significant safety issues for road users and adjacent land. A culvert is a drainage structure that allows water to pass beneath a roadway, and when it becomes blocked or collapses, it can cause flooding on the live carriageway or adjacent land. This can create a hazardous conditions for road users, making the road surface slippery and potentially causing vehicles to skid or aquaplane. It can also damage the road surface, and the surrounding environment, resulting in costly repairs and potentially long-term disruptions and further maintenance issues.
In addition to the safety risks posed to road users, blocked or collapsed culverts can also pose a risk of imminent failure of the carriageway or embankment above the culvert. This can cause serious structural damage to the roadway, leading to significant repair costs and potential closures.
Highways maintainers in the UK are responsible for identifying and repairing blocked or collapsed culverts as part of their maintenance duties. They use various techniques, including unblocking or clearing debris, repairing or replacing damaged sections, and performing regular inspections to ensure the culverts remain in good condition. By proactively addressing these issues, highways maintainers can help prevent accidents and damage to the road surface and surrounding environment, promoting the safety and functionality of the road network.
To mitigate the risk of blocked or collapsed culverts causing safety issues and damage to roadways, it is essential for maintainers to identify and repair these defects promptly. This involves inspecting culverts regularly and cleaning them when necessary, as well as repairing any damage or defects that are found. By doing so, maintainers can help to ensure the safety of road users and prevent costly structural damage to the roadway.
Some of the defects that can occur outside of vegetative and material blockages are;
- Concrete culverts: cracking, spalling, delamination, corrosion of reinforcing steel, erosion of concrete, leaks, and joint separation.
- Brick arch culverts: cracks in the bricks, sagging or bowing of the arch, voids or cavities in the brickwork, crumbling mortar joints, and erosion of the foundation.
- Plastic culverts: deformation, buckling, cracking, splitting, joint separation, abrasion, and crushing.
It’s worth noting that the specific defects that can occur in each type of culvert will depend on factors such as the age and condition of the culvert, the material it’s made from, and the environmental conditions it’s exposed to.
Inspecting culvert assets is an important part of ensuring that they are in good working order and condition. Here are some steps that could be taken to inspect culvert assets:
- Conduct a visual inspection: Start by conducting a visual inspection of the culvert. Look for any signs of damage, such as cracks, corrosion, or deformation in the structure, and ensure that there are no signs of wear and tear that could compromise the culvert’s structural integrity.
- Check the inlets and outlets: Check that the inlets and outlets of the culvert are clear and not blocked. Ensure that the inlets are properly connected to the road surface, and that there is no evidence of erosion around the outlets.
- Check the surrounding area: Inspect the surrounding area to ensure that there are no signs of flooding or other water damage. Check that any adjacent land is not being affected by the culvert, and that there are no signs of soil erosion or instability.
- Test the flow rate: Carry out a flow rate test to check that the culvert is capable of coping with the amount of water it is designed to handle. This can be done by pouring a known amount of water into the inlet and measuring the time it takes for the water to flow through the culvert.
- Check for debris or blockages: Look for any signs of debris or blockages within the culvert, such as sediment or leaves. This can be done by using a camera or other specialized equipment to inspect the interior of the culvert.
- Document your findings: Document your findings from the inspection and use this information to inform any necessary maintenance or repair work.
Regular inspections of culvert assets can help to ensure that they are in good working order and that any necessary maintenance is carried out in a timely manner. By taking a proactive approach to maintenance, potential issues can be identified and addressed before they become more serious problems.