manhole

[dada]

on the approved bld gregs for my extension is a section on manholes.
it reads..
manholes to be constructed with 225mm engineering brickwork on concrete slab foundation. Concrete haunching to be provided in channels in manhole. this is pretty double dutch to me - can anyone expand/show a diagram etc plese
thanks

 

[stuart45]

Set your channels and pipe work out first, then built the brickwork up enough to do the benching. Then take the brickwork up to the required height. Which is the particular bit that you are having trouble with? How do you put a diagram on here? I'm not much good with computers.
You might be able to use a plastic manhole.

 

[noseall]

first you dig your trench and lay the pipework. any vulnerable connections or junctions will need access so these are formed with an open channel arrangement.

you then construct a chamber around these junctions.

this involves laying a 3' square pad of concrete around the pipes and channels, only up to the channel height and at about 100mm thick.

you then build the chamber walls, one brick thick, (225mm) so that the inside dimensions are 23" x 17", or so that the chamber lid just fits without falling into the manhole!

after laying about 4 courses or so you would then lay the concrete haunching or benching. this is the smooth, contoured, sloping concrete formation at the base of all manholes.

you then continue with the brickwork up to g/l. then set the frame and lid.

alternatively there are precast manhole rings or plastic chamber bottoms and risers.

http://www.miltonpipes.co.uk/products/inspection.asp

 

[stuart45]

That's a much prettier picture than the one I've just drawn noseall. I've just ripped mine up.

 

[noseall]

That's a much prettier picture than the one I've just drawn noseall. I've just ripped mine up.

yeah, but you pipped me to the post.

 

[dada]

super, thank you.