Manhole Rehabilitation: Understanding The Core Concepts & The Replacement Process

By Author: Danniel Kollen
Total Articles: 24
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A smooth, long drive feels pleasant until and unless the wheels cross old and damaged manholes. It’s a nuisance to those who drive vehicles for work or pleasure. Not only do they act as road hazards but also create safety issues and sewer blockages. Natural disasters like earthquakes, root intrusions, water erosion, asphalt deterioration and weather; and manmade invasions are solid reasons for manhole deterioration. Fortunately, manhole rehabilitation takes care of them, leaving behind freshly benched manholes with a proper cover enclosing it.

Signs of Manhole Deterioration
Now, every manhole over time surrenders to the external elements – both natural and manmade. As more time passes by, those magnify. But for a layperson, it’s easy to identify the signs. Look for the following to plan a manhole benching or repair:

• Cracks appearing around manholes
• Ill-fitted covers
• Water pooling above
• Visible damages

If you come across any of the mentioned, go straight for manhole repair. When you do so, you will encounter three techniques popular across Ireland. ...
... Let’s check them out below and explore their specialities.

Manhole Rehabilitation Techniques

Without beating around the bush, let’s hear from the horse’s mouth.
1. Lining
This method aims at structural reinforcement to block groundwater runoff, besides safeguarding people from gas leaks off sewer. The process is a bit gripping with specialists cleaning its interior first, emptying loose debris and laying a custom-fit liner within. As the liner expands, it creates a new interior, adding integrity to the manhole.

2. Grouting
This technique takes care of water runoff and is not as intensive as the prior. Specialists, under this method, quickly prepare a chemical solution and injects it into the fissures to seal them. Everything is done, keeping in mind the manhole’s materials, the pavement surrounding it and the local soil. The ultimate aim is to reinforce the manhole structure, and grouting proves quite effective here.

3. Polyurethane spray
Groundwater and corrosive gases often corrode manholes. Urethane materials cure them, leaving behind zero leakages. Applied with a spray, the coating acts a barrier, thickening the lining for a reinforced structure. While this might sound time-consuming, the reality is entirely different. The process completes in about 8 seconds with the manhole and sewer resuming to a workable condition within just an hour.

Manhole Replacement Process
Sometimes the rehabilitation techniques seem insufficient, convincing all to go for a quick replacement. Wet concrete hardening underwater or along the sides create such a scenario, leaving behind professionals only one way to resolve the blockage. Unlike the rehabilitation techniques, the method is intensive, with specialists taking quite a few days to finish the task.

The process starts with excavation, all the way down to the sewer mains. New structures replace manholes following a sewer bypass installation. Sometimes, professionals build up a fresh manhole to facilitate sewer line maintenance and at other times, abandon that step when it’s no longer needed.

A final word of advice will be to involve a sewer line expert or a manhole repair specialist for that professional finish and of course, for your safety.

Author Bio:
The author takes a keen interest in civil engineering projects of which manhole benching, replacement and rehabilitation are common concepts. She spreads awareness about those to readers and keeps them updated with innovative trenchless techniques.