M7 - Nenagh to Limerick

Berty

For them to bypass it they would have to purchase new land but the NRA is going to pay for it and the contractor is not allowed enter into this scheme and offer to buy the land for infrastructure needs.

Anyway they cannot bypass it to the East because the bog heads all the way over towards the R503.

They cannot go the other way because it would have to go through Castleconnel or cross the Shannon and cross back again.

So for me I assume they MUST fix the problem because there is no way around it.

crucamim

Berty wrote: »

So for me I assume they MUST fix the problem because there is no way around it.

Can the problem be fixed without taking a new route?

murphaph

crucamim wrote: »

Can the problem be fixed without taking a new route?

With enough money, yes.

123easy

murphaph wrote: »

With enough money, yes.

Absolutley, every engineering problem can be solved but it the cost might probably be prohibitive!

Blazer

Berty wrote: »

They cannot go the other way because it would have to go through Castleconnel or cross the Shannon and cross back again.

.

Castleconnel's a shíthole...bulldoze it and build through

Berty

crucamim wrote: »

Can the problem be fixed without taking a new route?

murphaph wrote: »

With enough money, yes.

123easy wrote: »

Absolutley, every engineering problem can be solved but it the cost might probably be prohibitive!

People scoffed at the idea of digging a tunnel under the English Channel but Sir Edward Watkin took up the challenge in the late 1800's.

Never say never.

gryff

Berty wrote: »

People scoffed at the idea of digging a tunnel under the English Channel but Sir Edward Watkin took up the challenge in the late 1800's.

Never say never.

I have it!.. I fckn have it.... tarmac over the dodgy bit...a good shlap of tarmac mind you... put in a 100 kph limit for the 600m of dodgy bit... and
ban trucks artics etc...send them off at birdhill... cars only on the m-way..
meanwhile... on the castleconnell side of the boggy section rebuild the road...but with much deeper and denser piles this time...
easy !

D.L.R.

gryff wrote: »

I have it!.. I fckn have it.... tarmac over the dodgy bit...a good shlap of tarmac mind you... put in a 100 kph limit for the 600m of dodgy bit... and
ban trucks artics etc...send them off at birdhill... cars only on the m-way..
meanwhile... on the castleconnell side of the boggy section rebuild the road...but with much deeper and denser piles this time...
easy !

No thinking outside the box please, this is Ireland. Everyone remain in the box at all times for your own safety.

Stark

Ah yes, what engineering problem can't be solved with a 100km/hr limit?

AlanD

A 600m bridge over the bog will do the trick.....easy peasy. Pity the man building the road is broke!

The solution he may come up with is we have to stop, get out of our cars, push them 600m and start off again

Berty

It is a bridge essentially.

A bridge has piers/columns - The road has piles driven into the bog.

A bridge has a deck made with concrete and rebars - The road has this also.

The road also has rubber to create a barrier between the piles and the concrete surface. On top of this there are a number of layers of aggregate and then some blacktop.

A bridge essentially would carry less weight but it would have to be two bridges like the Fermoy bypass.

The issue I see with this is the uncertainty of the bog and the chance of the bridge shifting and moving and therefore the potential of it collapsing / falling over.

The Limerick Post today reported that the road "should" be open by the end of the year and they are NOT going to try another route. What the exact solution is nobody is sure.

AlanD

Berty wrote: »

The issue I see with this is the uncertainty of the bog and the chance of the bridge shifting and moving and therefore the potential of it collapsing / falling over.

What if they anchored the bridge on the sound land either side of the magic bog? So the driving deck floats over the dodgy bit.....

roosterman71

Have you ever seen a bog?? I fear that the "sound land" either side could be miles from the problem

AlanD

roosterman71 wrote: »

Have you ever seen a bog?? I fear that the "sound land" either side could be miles from the problem

you are probably right.

How about draining the bog?

Berty

AlanD wrote: »

How about draining the bog?

Free Peat. Warm up your house for FREE.

However, it might be easier to say PEAT ONLY €1 per block meaning people will simply steal it emptying the bog much quicker.

cjpm

It was never invisaged that the bog would be so deep, a massive mistake by those who selected the route IMHO. Once the contractor was on site he had to follow the selected route, and naturally they would look at the cheapest solution to accomplish this.

Berty wrote: »

It is a bridge essentially.

A bridge has piers/columns - The road has piles driven into the bog.

A bridge has a deck made with concrete and rebars - The road has this also.

The road also has rubber to create a barrier between the piles and the concrete surface. On top of this there are a number of layers of aggregate and then some blacktop.

A bridge essentially would carry less weight but it would have to be two bridges like the Fermoy bypass.

The issue I see with this is the uncertainty of the bog and the chance of the bridge shifting and moving and therefore the potential of it collapsing / falling over.

Unfortunately, some of the piles used were over 30m long and still never hit solid ground. Therefore a lot of the piles are friction piles and not end bearing. A bridge would need a really solid foundation at each pier, so those friction piles would have been useless as the are liable to move slightly (or more significantly!!)when loaded.

At least with a load of piles, all capped, and then covered with fill, together the risk of movement is less critical as they should move together and not cause too much of a problem. Or so the theory goes.....

However from what i understand on this scheme some of the piles moved more than others thus creating a huge problem. I think in hindsight maybe the contractor should have capped groups of the piles together, maybe by creating narrow concrete ground beams which transverse the roadway. At least this would ensure that the piles on the edge would be prevented from displacing away from the road.

AlanD wrote: »

you are probably right.

How about draining the bog?

Massive environmental implications i'm afraid. Also bogs tend to be a low point so draining it would also be extremely difficult and costly, also bogs can be up 90% water!

lukejr

cjpm wrote: »

Unfortunately, some of the piles used were over 30m long and still never hit solid ground.

Where did you hear this? My understanding is that all the piles went down to the bed rock. There would be no point sticking them in without grounding them in the bed rock.

The issue will be fixed, I just hope they get it done soon.

Sponge Bob

cjpm wrote: »

It was never invisaged that the bog would be so deep, a massive mistake by those who selected the route IMHO. Once the contractor was on site he had to follow the selected route, and naturally they would look at the cheapest solution to accomplish this.

It will go down in the history of UK Geotechnical Engineering as an epic fail. Some serious international expertise was used to figure out how to get across the Mire of Gloom in Annaholty and it is probably safe to say they did not deliver.

also bogs can be up 90% water!

I believe this one to be THE soggiest and also more or less the deepest bog ever found here and then after penetrating the bog there is up to 20m more of gloop before they hit something solid with the piles.

The stories about the piles disappearing clean into the bog ( see this thread in Jan/Feb) and how they cautiously spaced the machinery apart for fear that were they close together they would all be swallowed be the Mire of Gloom is rather amusing I thought

cjpm

lukejr wrote: »

Where did you hear this? My understanding is that all the piles went down to the bed rock. There would be no point sticking them in without grounding them in the bed rock.

The issue will be fixed, I just hope they get it done soon.

I read it in some geological presentation if i remember correctly, i think the link was posted somewhere in this thread.

There are 2 types of piles, friction and end bearing. Friction are only used for moderate loading when the bed rock is too deep.

phog

cjpm wrote: »

Unfortunately, some of the piles used were over 30m long and still never hit solid ground.

I heard that they met solid ground but because of their lenght that some of them sheared and this wasn't noticed until the road began to sink. I also heard that they have found a solution but that they have to monitor the road before, during and after the solution is being put in place thus dragging the opening out.

When??????? I wasn't told.

Deedsie

phog wrote: »

I heard that they met solid ground but because of their lenght that some of them sheared and this wasn't noticed until the road began to sink. I also heard that they have found a solution but that they have to monitor the road before, during and after the solution is being put in place thus dragging the opening out.

When??????? I wasn't told.

Would you consider it a reliable source that you heard it from? Someone involved in the project?

crucamim

Does anyone know just how deep this bog is?

Sponge Bob

I think the bog of doom had 50m onsite cast piles ( you basically could not move them by road) but the mire of gloom used shorter piles than that.

All in links jan/feb time in this thread somewhere, search for LLoyd or lloyd acoustics

L1011

Stark wrote: »

Ah yes, what engineering problem can't be solved with a 100km/hr limit?

Those that require a 60km/h limit, of course.

Sponge Bob

Here it is

http://www.lloydacoustics.com/lasite.nsf/0/CC641EC7EFCFE77B802576C800480E97

Read the whole article carefully.

In photos of the DIFFERENT rigs used in Drominboy and Annaholty (below) you will see the Drominboy piles were MUCH longer and were dropped and driven down in one piece and then cut to size. The Piles were 40m or 50m long in places and hit ground within 40 and 50m and were then cut off.

But Annaholty bog was much softer than Drominboy. The platform the piledrivers used wobbled like a mad jelly.

The Annaholty piles were jointed ( segmented). The bog was so soft that the piledriver would have sunk into it after lifting the pile upright ......had the pile been long enough to reach bottom....c 40m down in places. So they used shorter piles.

Pages 13 and 14 of this 'presentation' clearly show the difference in the piling plant.

http://www.geolsoc.org.uk/webdav/site/GSL/shared/pdfs/specialist%20and%20regional%20groups/TVGS_IGS_presentation_Jan2008.pdf

Drominboy appears to be solid enough now but has anyone had a look at it recently by any chance ????

freighter

The N5 between tarmonbarry and strokestown had the same problem when it was built about 10 years ago maybe its less... I remember wills done the job but they dug out most of the bog i remember. I seen track machines there, they were like insects below in the bog.... They made better progress than this scheme though

phog

Deedsie wrote: »

Would you consider it a reliable source that you heard it from? Someone involved in the project?

From someone who knows one of the LA engineers.

crucamim

Sponge Bob wrote: »

Here it is

The Piles were 40m or 50m long in places and hit ground within 40 and 50m and were then cut off.

But Annaholty bog was much softer than Drominboy. The platform the piledrivers used wobbled like a mad jelly.

The Annaholty piles were jointed ( segmented). The bog was so soft that the piledriver would have sunk into it after lifting the pile upright ......had the pile been long enough to reach bottom....c 40m down in places. So they used shorter piles.

Drominboy appears to be solid enough now but has anyone had a look at it recently by any chance ????

You seem to be saying that its depth was not the only aspect of the problem which the bog posed and that its softness also posed a problem in that it was unable to support a piledriver platform big enough to cope with piles long enough and strong enough for the purpose. Have I understood you correctly?

P.S. If the bog is very soft, what keeps the piles upright? Are they connected to each other to give each other strength - like trees in a forest?

I read something (in the link which you provided) about "sacraficial anchors". Are these blocks of concrete dropped into the bog to thinken it up and so support the piles? Or is a "sacraficial anchor" a block of concrete with holes in it which is let slide down a pile to help stabilise it? Or is it a block of concrete with many holes in it which is let slide down several piles simultaneously in order to bind them to each other and so stabilise the structure?

Sponge Bob

Read this so ....carefully note the dates

http://www.nce.co.uk/fully-instrumented-rigs-are-installing-piles-over-two-bogs-as-part-of-a-major-road-scheme-in-ireland/169699.article

31/10/2007

Annaholty is a peat bog down to a maximum 12m, overlying sand. Piles are being driven to an average depth of 30m, with pile loads of between 49t and 80t, and pile spacings of 2.5m on a herringbone grid pattern.

Each pile is finished with a 600mm deep reinforced cap either 1m2 or 1.2m2. Each pile is a stand alone element of the works because pile caps are independent of one another.

A geotextile layer spans the pile caps supporting the 3m to 8m high embankment to create a load transfer platform.

Such is the scale and programme of the works that the subcontractor has set up a pile casting yard on site, where 12 site workers are employed. This enables the team to fabricate much faster and more cost-effectively than transporting 120,000m of piles 354km from the contractor's yard at Lisburn, just outside Belfast.

Casting began at the end of May with an average 80 piles per day – about 800m per day and a total of 4000m per week. The maximum number it can produce on site is 960m per day, or 4800m per week.

The contractor began installing the first working piles at Annaholty in July using two Junttan PM20 hydraulic piling rigs, each driving up to 600m a day. The rigs are fully instrumented and produce a computerised read out for each individual pile installed, which can be analysed for quality control purposes.

"Although not in real time, the instruments provide a range of data including information on pile reference numbers, the total number of blows struck, the hammer drop height and the final set, as well as giving an indication of the ultimate load bearing capacity and the type of pile modules used," says FK Lowry managing director Mark Walsh. "They also provide important graphical information for rate of penetration, drop height, set, driving resistance and driving stresses."

Piling at Annaholty is expected to complete in December. (2007) Following this, piling work will begin at Drominboy Bog. Options for this second phase are still being discussed with the client due to different pile sizes and pile loads required. However, the contractor anticipates being on site in November to complete all works by February next year. (= Feb 2008 in Drominboy)

It's what ??? May 2010 now ???

freighter

I travelled from limerick today from nenagh. Is it quicker to use the motorway from birdhill or the old road. I went up the old road and it was empty still has 100 kph speed limit but the guards had a checkpoint at the overbridge where the traffic lights are...

I came down the motorway it seemed longer..