UKC

Amazed how those flats are still standing.
Are those long concrete piles resting on bedrock?
Do you have to keep going until you reach rock when you're building?

Any structural engineers care to comment?

thanks

In reply to rubbercrumb: That's what I was wondering I'm not convinced that's the way to build foundations for something that size.

In reply to mypyrex: awfully spindly - but doing the job they were meant to I guess.

Do house builders keep going to bedrock too? <frets>

In reply to rubbercrumb:

(Roughly, because I'm sure someone will pick me up!) Three types of load bearing piles:

End bearing, where the tip of the pile rests on a supporting layer of material (your bedrock idea.)

Skin friction, where friction of the surface of the pile on the surrounding material transfers the load onto the surrounding material.

Combination of the above.

I expect and hope that the flats are on end bearing piles, as the lack of skin friction could cause failure if it is two or three. The piles are also quite slender now without the surrounding soil to support, so may fail by bending out of shape then collapsing.

When building foundations you only need to keep going until the load you are going to put on the earth will be supported without excessive settlement.

(Take this with a pinch of salt, I just finished a civ eng degree, but have no experience...)

More here, ( http://www.ehow.co.uk/list_6912389_types-foundation-piles.html ) be very careful when googleing piles, DO NOT click image search.

In reply to rubbercrumb: Speaking not as an SE, but a bricklayer with nearly 30 years of experience of foundations and construction,no,you don't have to keep going until you find bed rock. Many houses and flats are built off strip foundations,of a width and depth to suit the structure being built.
A minumum depth of 1 metre is generally stipulated in order to find load bearing subsoil,but you could go as deep as 2 metres in order to find this.
Piling,in it's many forms,generally takes place where the load bearing strata is deeper, and strip excavation would prove prohibitively expensive,and dangerous.Piles are driven down to the load bearing layer,and then a "ring beam" is cast across the top of them in concrete,to create a stable foundation.
HTH,
Structural engineers,I'm in the right area,no?

In reply to rubbercrumb:

If you think they are spindly, just look at some buildings that expose their structure. I think it just looks odd because the flats look so solid. I don't think you do have to hit bed rock - you would find this difficult in London for example, but obviously the ground 30m down tends to be a bit harder than on the surface.

In reply to jonnie3430: Took me so long to type my reply,yours was up by the time I posted! Sounds like a good honest educated man's answer to me!

In reply to rubbercrumb: What is more interesting is that the erosion was caused by a breach of a culvert causing subterainean erosion. The breach was first known about in May which is when the residents of the flats were evacuated. This is actually the latest development in a long running saga.

Now, I'm not a builder or enginner but it strikes me that buling above or very close to a culvert is asking for trouble.

In reply to stujamo:

Aye, but what is knowledge without experience?? (Though I do have experience of googleing piles....)

In reply to rubbercrumb:

These fairly modern flats were built on piles as the whole area is riddled with old mine workings. I've got a feeling that the site was an incident waiting to happen. I've had a look at the location ( Spencer Court, Newburn, Newcastle Upon Tyne) on Google Earth and something very strange was going on when the imaging was done. There are lots of pipes running past the adjacent site - looking as though they are draining what was a pond located upstream of the site. The site itself lies on the confluence of two drainage streams - and given the unprecendented rainfall event, something was likely to happen.

In reply to jonnie3430:

Indeed,but where my reply was belt and braces,yours was technically correct ;O)
Congrats on the degree,btw
(And I shan't be googling piles)

In reply to The Mole:

Not necessarily, if the piles extend below the depth of the culvert,which is after all a watercourse that has been contained in a pipe, hth

In reply to mypyrex:
I'm not convinced that's the way to build foundations for something that size.

Piles can be tenacious buggers, if you had piles that big you wouldn't be going anywhere fast

In reply to The Mole:

There are load and loads of urban areas where small brooks/ rivers have been diverted into culverts and built over. If the culvert and the earth supporting it are structurally sound it shouldn't be a problem (except that the area floods when the culvert reaches capacity).

In this case it looks like the culvert was built on a formation suffering from subsidence and the water escaping from the culvert has probably been washing away the soil beneath for a number of years!

In reply to stujamo:

I'm an architect and this is spot on... but what do we know SE do design below ground structure for us. I'm sure glad that we didn't design them and it isn't us reaching for the PI

In reply to Lukeva:

So what do you reckon? If the culvert is owned by the LA,is a long game of liabilty tennis,going to keep these people out of their homes for the forseeable?

In reply to stujamo: Sure, terrible situation for the residents without the issue of fault. I can’t see either the developers or LA accepting liability without extensive adjudication or more likely civil action, with many potentially exposed parties. Imagine trying to underpin that lot!? Can’t see how? The fact that they are still standing is a testament to the quality of modern construction.

In reply to Lukeva:

Agreed. A lot of people will fail to see this though.
(Oh no,here we go.....) ;O)

In reply to Lord of Starkness: The Google Earth image may have been taken since May when the problems first occurred. The pipes may be part of the temporary measures put in place at that time to divert water away from the breached culvert whilst it was repaired.

Your points about the confluence of the drainage systems from the higher ground above is almost certainly correct
Mark

In reply to rubbercrumb:
Scary stuff,
from folks I know: The LA deemed the culvert ok when the development was built.
The culvert partially collapsed during flooding in May, they (the LA) have been overpumping since; that’s the steel pipes that you can see in the vid.
I don’t know what was or had been done in the ongoing culvert repair, but when you get flooded out half way through repair works then, well, there you go.
The fact that it’s is still standing is more to do with the quality of our design standards/building regs/and the general overestimating that goes on in foundation design. (err well on the safe side).
I would think that if it’s not showing signs of movement/cracking then you could probably back fill it with foam concrete and it’ll be fine.
What you do with the culvert is another thing.........

In reply to The Mole:

The google earth imagery is shown on screen with a March 2012 date.

There is a fascinating feature with google earth that allows you to see the 1945 imagery. The entrance to Newburn Colliery is less that 400 metres away.
As I said earlier the whole area is riddled with old coal mine workings - hence the piling.

In reply to stujamo:

Not really. This just puts whatever work the LA was doing back to scratch.
As for the developers PI; from what I gather the culvert was there before the building (someone local may know better).
It’s usually the case that the LA has no one to blame but themselves for giving planning permission to things that are an accident waiting to happen. There’s nothing wrong with the building, or it’s foundations; evidently, it’s just in the wrong place.

In reply to daWalt:

Thanks for clearing that up for me,didn't realise that there was work going on to the culvert prior to this.

In reply to rubbercrumb:

Is it going to be possible to back-fill it?

In reply to rubbercrumb:

Could I ask for those not familiar with Newcastle or these buildings for a link in an image?
Thanks

Interesting thread BTW

In reply to rubbercrumb: I'll be interested to see what solution is decided upon

In reply to stujamo:

God,did I just say that??!!
I'm turning into my father!!

In reply to Indy:

Image 6: http://www.bbc.co.uk/news/in-pictures-19727458

In reply to Lord of Starkness:

i live just up the road from the area & grew up near the flats & culvert.
the pond that you see is not actually a pond. there is a stream or burn that runs down through a wooded valley (dene) from the fells to the north, where it reaches the "pond" it goes through a culvert for 3rd mile into the tyne, the reason for the culvert is that during the 18-1900`s the whole area was railway lines for the coalpits to the north & west (throckley & wylam) & the coal was transferred down waggonways to the tyne , where there were large marshalling yards & steelworks, railway lines need level tracks, so the stream(burn) was redirected via a brick & concrete culvert (at least100- 150 year old!!)
back in june during the last storms, the upper part of thei culvert collapsed & the water built up, creating the large "pond", the water level rose near on 40ft flooding nearby stables & spilling over & flowing thru the estate, before finding its way back into the culvert lower downstream.
mcalpine construction have been there since with heavy duty pumps (thats the large pipes you can see) pumping the pond down to the culvert lower down, to stop the burn flowing thru the estate, however after this recent storm, the waters rose again & the force of the flow washed away the road & flowed back into the culvert taking with it everything in its path, large brick retaing walls, tarmac roads, hundreds of tons of earth etc etc, this flowed down the culvert where it became well & truly jammed, again the resulting pressure built up, & simply burst the concrete roof of the culvert clean off & the resulting debris (hundreds & hundreds of tonnes!!) gushed out onto the road burying everything in its way (a car driver luckily jumped out of his car & watched it disapear under the debris).
skara.

In reply to stujamo:

In reply to stujamo:

God,did I just say that??!!
I'm turning into my father!!
............

lol

I've always been quite like my father, it's not something we can fight I don't think. ()

In reply to skarabrae: it is yet to be decided wj=ho is responsible, from what i believe, the duke of northumberland may own some of the land or the culvert (i believe he has hired mcalpine to assist in the matter)
some are blaming dunelm homes (the builder of the estate).
its to eraly to say, but its going to be a long process, thats even before the culvert can be re-built!!

In reply to rubbercrumb: At a guess the name Newburn has some past connection to a burn or water course. Has the property been built in the original burn?

In reply to auser:

see my replies above ^^

the burn runs through a culvert to one side of the estate.

In reply to skarabrae:

Thanks, interesting background. I often cycle up the hill on my way home, it's amazing what's under your feet.

In reply to Timmd:

Been quite like my mum too I should add, a bit of both plus something extra.

In reply to Timmd:

Been quite like my mum too I should add, a bit of both plus something extra.

What, a shemale?

In reply to The Mole:

There is a lot more of it than you think.
The link below shows what is under Sheffield station, the confluence of the Sheaf and Porter Brook.
http://www.28dayslater.co.uk/forums/showthread.php/21878-Megatron-Sheffield...

There are loads of similar things under many towns.

The website is well worth a look, there are some interesting bits under Sheffield