Ramped backdrop connection.

[jwill]

Got a bit of a dodgy connection to do. Not much room to play with and also got an invert difference of around 300mm from internal over-site to drain invert. Also got a storm drain running next to and at more or less same invert as foul around 1 1/2" lower. Theres a few ways to skin a cat but this seemed to make sense in my mind. I was originally planning to cut a plastic IC in but was snookered with the storm drain.

Being brave putting it on here let me know what you think.

[seanandruby]

Can't you turn the chamber longways so your backdrop is outside, coming up on a 90?. That way you can raise you concrete riser higher off those clay pipes and surround your new pipes in concrete to stop deformation. Ideally you need a stub pipe 150 ml outside chamber and 600 rockers on the existing run. Hope your not a dry lean fan?

[jwill]

I could switch the manhole but it's going to limit ability to rod back up the backdrop. You've got a 1m gap no matter which way ic is positioned or if backdrop is in chamber or earth. Don't worry the riser is just a dry fit at the moment it actually sits around 3" off those pipes with the bottom having a 4" ish foundation. I've actually had to cut a notch in the top of that riser to accommodate it coming up on the branch.

What do you think a flex coupler both sides of wall?

[jwill]

Also I have means of rodding down main run further up

[lutonlagerlout]

in my experience the back drop usually has to be outside the chamber where possible,and you core a hole in the chamber to allow for rodding
we did do 1 similar to yours but it was a lot deeper maybe 1500 mm and we had to clip the pipe every 450
it will probably work but the pipe needs to be secure
LLL

[seanandruby]

I just think the short radius 45 is asking for trouble. A longer 45 would be more acceptable.

[jwill]

I can flip the risers to have it all outside but I really don't see what benefit it achieves. If bco has a problem with it being inside the chamber I could drop a 320mm set of risers inside and concrete around! Being as less than 609 invert. I think the key is to compo that branch well where it comes into ic to secure and bench up properly.

Fair comment 're short radius 45 but a lot of the drawings online showed short rad 45. Also the difference in inverts means I'm struggling to fit long radius in there.

Thanks for comments anyway. I'm getting the not ideal but will probably work ok vibe!

[seanandruby]

No worries
It's one of those run with it jobs. I have done plenty of inside backdrops in a similar arrangement, should be ok there the grano will hold it all on place. Nice to hear the word "compo", no one uses it darn sarf :;):

[Dave_L]

It looks fine to me, you're not in an ideal situation there anyway, I don't think any reasonable BCO would have any problems with it as I see it.

[jwill]

Well got it done today. Obviously couldn't get a level invert for the same reason I couldn't just chop a pvc IC into it - the storm drain running parallel at similar invert. Taking the 45 radius comments onboard I swapped the 45 for a 30 and a 15. Not only did it give me more of a swept bend but it gave me a bit more play sweeping the slipper round in direction of flow. Helped out quite a bit. Had to cut top riser down 1 1/2". Cant believe how hard they are to cut that way!

Set everything on stiff ish concrete with benching ontop. May have said compo because all I really had for finishing was building sand! Lets hope it bonds to the concrete as they were done on same day and is strong enough! I suppose really I should have benched over all the joints on the pipe so nowhere for rats to nest. Could always go back on that I suppose. Anyway not a perfect job by any means but hey ho should perform as intended.

Go easy!

[seanandruby]

Good job will. Would have liked to grano benching, or at least one to one sharp sand and cement, yes cover pipes with a good slope. You'll never stop rats, they will find a home.

[lutonlagerlout]

yes a good job IMHO too
as Sean says bench over the pipes and a steel plug in the rodding access
those little furry fellas can jump
LLL

[jwill]

Ok over bench with sharp and sbr. Think I will show bco first

[Dave_L]

Lovely job that. Just bench over the pipe and jobs a good'un