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Posted: Wed Aug 01, 2012 9:04 am
by mikec1972
Does anybody have any experience of using these precast headwall units by by athlon etc, there's also the coventional cast in-situ mini concrete headwall arrangement or maybe sandbags, it's a rural area and the headwall is for a mainly dry ditch with very little flow, 600dia conc pipe,GL to base of ditch is circa 1m deep.
Posted: Wed Aug 01, 2012 8:38 pm
by Dave_L
Sounds expensive, for such a low-flow environment, what about building your own, forming it with concrete/stone?
Posted: Wed Aug 01, 2012 9:18 pm
by haggistini
Or slabs in a wide u type shape laid on lean mix concrete
Posted: Thu Aug 02, 2012 7:37 am
by GB_Groundworks
Not so much here but a mate uses them
Lots in the states, they need seating then concreting in all around then a lot of rip rap or large sugar stone surrounding them to stop them washing out and being undercut.
Are you discharging into another water course or lake/pond?
The few times we've done them we have just formed a shutter and mass poured a big lump of concrete to hold the 600mm pipe.
They look like a good bit of kit, is it a private job? As I bet they cost a bit, and if you are working within 8 metres of a river you have to contact environment agency and get permission from them, been there and got a stern telling off from them in the past. We own about 400m of the river goyt and had a few run ins with them about doing work.
Edited By GB_Groundworks on 1343889755
Posted: Tue Aug 07, 2012 2:25 pm
by mikec1972
Thanks for the replies, was thinking of going for the flag stones laid on concrete option, had prices come in from althon at £2k a pop! Like you say its only a private job so something fairly cheap/simple but with a little durability, was going to bed the 450 dia culvert pipe on 150 sub-base then surround in 150 concrete with concrete flag stones on edge forming a u around each of the inlets and outlets
Have a detail for one here but not sure how to post images, anyone any ideas:), btw thanks for all your replies, this is a great site!