Viewing footage of the crash site on the BBC news website, it seems that
the concrete barriers (Jersey Barriers?) didn't provide much, if any,
resistance to the vehicles crossing the central reservation. I had
assumed that they would have been at least capable of doing so. Weren't
the metal armco barriers capable of this?

So what is the drive to concrete barriers for? Anyone know?

Cheers.

In article ,
David Paste writes

Viewing footage of the crash site on the BBC news website, it seems that
the concrete barriers (Jersey Barriers?) didn't provide much, if any,
resistance to the vehicles crossing the central reservation. I had
assumed that they would have been at least capable of doing so. Weren't
the metal armco barriers capable of this?

So what is the drive to concrete barriers for? Anyone know?

If you want to promote discussion on website footage, it might be an
idea to provide a link to that footage or a news article.

Unless you bolted those concrete barriers together yourself then it
would be nice if you had marked your post with an 'OT:' prefix.

--
fred
it's a ba-na-na . . . .

Unless you bolted those concrete barriers together yourself then it
would be nice if you had marked your post with an 'OT:' prefix.

or better still, post in the correct newsgroup.

In article , Andrew Gabriel
writes
Unless you bolted those concrete barriers together yourself then it
would be nice if you had marked your post with an 'OT:' prefix.

or better still, post in the correct newsgroup.

Fair comment but diy aside, this is fundamentally an engineering
newsgroup.
--
fred
it's a ba-na-na . . . .

On 09/12/2014 14:54, David Paste wrote:

Viewing footage of the crash site on the BBC news website, it seems that
the concrete barriers (Jersey Barriers?) didn't provide much, if any,
resistance to the vehicles crossing the central reservation. I had
assumed that they would have been at least capable of doing so. Weren't
the metal armco barriers capable of this?

Armco and tensioned wire barriers are designed to slow vehicles that
impact them at a shallow angle, without throwing them back into the
carriageway. They were never intended to resist a direct impact by a
heavy vehicle.

So what is the drive to concrete barriers for? Anyone know?

They take up less width. The original specification called for a central
reservation of at least 15 feet wide, which gave plenty of room for two
rows of Armco. However, as motorways are being expected to carry far
heavier traffic than many were originally designed for, central
reservations and emergency vehicles lanes (aka hard shoulder) are being
sacrificed to fit more lanes in.


--
Colin Bignell

On 09/12/2014 14:54, David Paste wrote:

Viewing footage of the crash site on the BBC news website, it seems that
the concrete barriers (Jersey Barriers?) didn't provide much, if any,
resistance to the vehicles crossing the central reservation. I had
assumed that they would have been at least capable of doing so. Weren't
the metal armco barriers capable of this?

Not especially. I have seen concrete mixers and the like go through them
like they were not there. Bad one not far from me a few years back.

A house not far away used to regularly get partially demolished by armco
penetrating muppets that entered a bend too fast. That hasn't happened
since they replaced it with a solid concrete buttress so I guess they
are more resilient. The new solid defences and livery would appear
to intimidate people into slowing down for the tight bend.

So what is the drive to concrete barriers for? Anyone know?

Stopping cars and glancing incidence events. I doubt there is anything
realistic you can do to stop a 40T HGV with a narrow central barrier if
it is travelling at the speed limit and a closing angle 30 degrees.

I did wonder if the idea is to intimidate the outside lane. The only
advantage they seem to have is that they block oncoming headlights more
effectively than the armco but that is all I can see as an advantage.

--
Regards,
Martin Brown

In article ,
Nightjar \cpb\@ insert my surname here wrote:
On 09/12/2014 14:54, David Paste wrote:

Viewing footage of the crash site on the BBC news website, it seems that
the concrete barriers (Jersey Barriers?) didn't provide much, if any,
resistance to the vehicles crossing the central reservation. I had
assumed that they would have been at least capable of doing so. Weren't
the metal armco barriers capable of this?

Armco and tensioned wire barriers are designed to slow vehicles that
impact them at a shallow angle, without throwing them back into the
carriageway. They were never intended to resist a direct impact by a
heavy vehicle.

So what is the drive to concrete barriers for? Anyone know?

They take up less width. The original specification called for a central
reservation of at least 15 feet wide, which gave plenty of room for two
rows of Armco. However, as motorways are being expected to carry far
heavier traffic than many were originally designed for, central
reservations and emergency vehicles lanes (aka hard shoulder) are being
sacrificed to fit more lanes in.

I also think that the Armco barrers were too low for many modern vehicles
where the CofG is too high. They roll over the barrier into the oncoming
carriageway.

--
From KT24

Using a RISC OS computer running v5.18

On 09/12/2014 16:31, charles wrote:
In article ,
Nightjar \cpb\@ insert my surname here wrote:
On 09/12/2014 14:54, David Paste wrote:

Viewing footage of the crash site on the BBC news website, it seems that
the concrete barriers (Jersey Barriers?) didn't provide much, if any,
resistance to the vehicles crossing the central reservation. I had
assumed that they would have been at least capable of doing so. Weren't
the metal armco barriers capable of this?

Armco and tensioned wire barriers are designed to slow vehicles that
impact them at a shallow angle, without throwing them back into the
carriageway. They were never intended to resist a direct impact by a
heavy vehicle.

So what is the drive to concrete barriers for? Anyone know?

They take up less width. The original specification called for a central
reservation of at least 15 feet wide, which gave plenty of room for two
rows of Armco. However, as motorways are being expected to carry far
heavier traffic than many were originally designed for, central
reservations and emergency vehicles lanes (aka hard shoulder) are being
sacrificed to fit more lanes in.

I also think that the Armco barrers were too low for many modern vehicles
where the CofG is too high. They roll over the barrier into the oncoming
carriageway.

Interesting page here

http://www.roadtraffic-technology.co.../feature67206/

and from it

On impact with a concrete barrier, any vehicle up to 13.5t in weight,
which includes most buses, coaches and 4x4s, will be contained and
redirected back to the highway. Steel barriers, on the other hand, are
only able to contain a 1.5t car, such as a Ford Focus.

CB wrote:

Interesting page here

http://www.roadtraffic-technology.co.../feature67206/

and from it

On impact with a concrete barrier, any vehicle up to 13.5t in weight,
which includes most buses, coaches and 4x4s, will be contained and
redirected back to the highway. Steel barriers, on the other hand, are
only able to contain a 1.5t car, such as a Ford Focus.

That would be the standard familiar "Armco". I don't think many
people realise how limited its capacity is.

There is a slightly stronger version which is an open box
section, and there are also assemblies with multiple horizontal
members, sometimes seen protecting bridge supports, or preventing
incursion onto railway tracks.

Chris
--
Chris J Dixon Nottingham UK


Plant amazing Acers.

On Tue, 09 Dec 2014 17:54:20 +0000, Chris J Dixon wrote:

CB wrote:

Interesting page here

http://www.roadtraffic-technology.co.../feature67206/

and from it

On impact with a concrete barrier, any vehicle up to 13.5t in weight,
which includes most buses, coaches and 4x4s, will be contained and
redirected back to the highway. Steel barriers, on the other hand, are
only able to contain a 1.5t car, such as a Ford Focus.

That would be the standard familiar "Armco". I don't think many people
realise how limited its capacity is.

There is a slightly stronger version which is an open box section, and
there are also assemblies with multiple horizontal members, sometimes
seen protecting bridge supports, or preventing incursion onto railway
tracks.

They built a new bypass near here a few years ago (the "New Thanet Way")
and the opening was delayed by a day when they realised they needed the
multiple one in front of a large electricity pylon! And this is a very
solid pylon - an "end of the line" one with cables down to a large
substation. Hate to think of the consequences if that were hit.


--
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £30a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor

On 09/12/2014 17:54, Chris J Dixon wrote:
CB wrote:

Interesting page here

http://www.roadtraffic-technology.co.../feature67206/

and from it

On impact with a concrete barrier, any vehicle up to 13.5t in weight,
which includes most buses, coaches and 4x4s, will be contained and
redirected back to the highway. Steel barriers, on the other hand, are
only able to contain a 1.5t car, such as a Ford Focus.

That would be the standard familiar "Armco". I don't think many
people realise how limited its capacity is....

Not really a problem in the days when few cars weighed over a ton and
there were two rows of Armco, on a wide central reservation.

Note that the concrete barrier redirects the vehicle back onto the
carriageway, while Armco was intended to keep it from doing that, to
reduce the risk of it colliding with another vehicle.


--
Colin Bignell

Wrecking more cars so they can sell new ones?
I'd imagine the cheaper the barriers can be built the better. However the
ones you mention which used to be the norm give and buckle to absorb the
energy, Concrete does not it seems.

Brian

--
From the Sofa of Brian Gaff Reply address is active
"David Paste" wrote in message
...

Viewing footage of the crash site on the BBC news website, it seems that
the concrete barriers (Jersey Barriers?) didn't provide much, if any,
resistance to the vehicles crossing the central reservation. I had
assumed that they would have been at least capable of doing so. Weren't
the metal armco barriers capable of this?

So what is the drive to concrete barriers for? Anyone know?

Cheers.

fred wrote:

or better still, post in the correct newsgroup.

Fair comment but diy aside, this is fundamentally an engineering newsgroup.

I think it's perfectly in order to post here about such things.

Bill

On 09/12/2014 19:48, Nightjar "cpb"@ insert my surname here wrote:
On 09/12/2014 17:54, Chris J Dixon wrote:
CB wrote:

Interesting page here

http://www.roadtraffic-technology.co.../feature67206/

and from it

On impact with a concrete barrier, any vehicle up to 13.5t in weight,
which includes most buses, coaches and 4x4s, will be contained and
redirected back to the highway. Steel barriers, on the other hand, are
only able to contain a 1.5t car, such as a Ford Focus.

That would be the standard familiar "Armco". I don't think many
people realise how limited its capacity is....

Not really a problem in the days when few cars weighed over a ton and
there were two rows of Armco, on a wide central reservation.

Note that the concrete barrier redirects the vehicle back onto the
carriageway, while Armco was intended to keep it from doing that, to
reduce the risk of it colliding with another vehicle.


I read somewhere that this was now seen as a benefit; Armco supposedly
slows stuff down more quickly than a glancing impact with concrete, so
that with Armco any secondary impacts are more severe, with more chance
of multiple shunts. With modern car construction and airbags, being
side-swiped by something bouncing off the concrete might be more survivable.

On 09/12/2014 15:56, fred wrote:
In article , Andrew Gabriel
writes
Unless you bolted those concrete barriers together yourself then it
would be nice if you had marked your post with an 'OT:' prefix.

or better still, post in the correct newsgroup.

Fair comment but diy aside, this is fundamentally an engineering newsgroup.

From the third photo here

http://www.bbc.co.uk/news/uk-england-essex-30391284

it looks as though they are simple gravity structures, not tied down to
the ground at all.

In article ,
newshound writes

From the third photo here

Thanks for the link.

http://www.bbc.co.uk/news/uk-england-essex-30391284

it looks as though they are simple gravity structures, not tied down to
the ground at all.

In that respect they would be similar to the tensioned cable crash
systems where the cables are only fixed and tensioned at something like
km intervals. In-between, some cables weave in and out of the relatively
light supporting poles and I think there are others that rest in deep U
shaped cups on top. They absorb the energy by dissipating it along a
long length.

I'm not familiar with the particular thin design in the pics but wider
ones in temporary use on motorway roadworks are keyed and bolted through
with multiple 20 odd mm studs to form a long continuous barrier and gain
a similar effect.

I suspect, and the pictures appear to indicate, that the individual
slabs are fixed together and that in the extreme forces of the
collision, the barrier gave way. I'd suggest that nothing short of tank
traps will stop a 32 ton artic and there needs to be some kind of cost -
benefit trade off.

I don't think other barrier types would have survived or performed any
better.

There was a documentary programme a very long time ago that showed the
testing and evaluation they carry out on new crash protection systems.
They are very thorough and do actually crash fully laden vehicles into
them at the speeds and angles that they are designed to resist.

--
fred
it's a ba-na-na . . . .

newshound wrote:

http://www.bbc.co.uk/news/uk-england-essex-30391284

it looks as though they are simple gravity structures, not tied down to
the ground at all.

Those look like the temporary type used during roadworks, rather than
the continuous slip-formed barriers.

On 09/12/2014 21:09, newshound wrote:
On 09/12/2014 19:48, Nightjar "cpb"@ insert my surname here wrote:
On 09/12/2014 17:54, Chris J Dixon wrote:
CB wrote:

Interesting page here

http://www.roadtraffic-technology.co.../feature67206/

and from it

On impact with a concrete barrier, any vehicle up to 13.5t in weight,
which includes most buses, coaches and 4x4s, will be contained and
redirected back to the highway. Steel barriers, on the other hand, are
only able to contain a 1.5t car, such as a Ford Focus.

That would be the standard familiar "Armco". I don't think many
people realise how limited its capacity is....

Not really a problem in the days when few cars weighed over a ton and
there were two rows of Armco, on a wide central reservation.

Note that the concrete barrier redirects the vehicle back onto the
carriageway, while Armco was intended to keep it from doing that, to
reduce the risk of it colliding with another vehicle.


I read somewhere that this was now seen as a benefit; Armco supposedly
slows stuff down more quickly than a glancing impact with concrete, so
that with Armco any secondary impacts are more severe, with more chance
of multiple shunts. With modern car construction and airbags, being
side-swiped by something bouncing off the concrete might be more
survivable.

Not being hit by something not bouncing off the Armco is even more
survivable.

--
Colin Bignell

On 09/12/2014 22:28, fred wrote:

I'm not familiar with the particular thin design in the pics but wider
ones in temporary use on motorway roadworks are keyed and bolted through
*with multiple 20 odd mm studs* to form a long continuous barrier and gain
a similar effect.

I suspect, and the pictures appear to indicate, that the individual
slabs are fixed together and that in the extreme forces of the
collision, the barrier gave way.

I'm thinking of Ronan Point, and I wonder whether an enquiry will find
that some/many of the bolts were not properly tightened, or even bolted
at all.

On 10/12/14 12:35, "Nightjar \"cpb\""@ insert my surname here wrote:
On 09/12/2014 21:09, newshound wrote:
On 09/12/2014 19:48, Nightjar "cpb"@ insert my surname here wrote:
On 09/12/2014 17:54, Chris J Dixon wrote:
CB wrote:

Interesting page here

http://www.roadtraffic-technology.co.../feature67206/

and from it

On impact with a concrete barrier, any vehicle up to 13.5t in weight,
which includes most buses, coaches and 4x4s, will be contained and
redirected back to the highway. Steel barriers, on the other hand, are
only able to contain a 1.5t car, such as a Ford Focus.

That would be the standard familiar "Armco". I don't think many
people realise how limited its capacity is....

Not really a problem in the days when few cars weighed over a ton and
there were two rows of Armco, on a wide central reservation.

Note that the concrete barrier redirects the vehicle back onto the
carriageway, while Armco was intended to keep it from doing that, to
reduce the risk of it colliding with another vehicle.


I read somewhere that this was now seen as a benefit; Armco supposedly
slows stuff down more quickly than a glancing impact with concrete, so
that with Armco any secondary impacts are more severe, with more chance
of multiple shunts. With modern car construction and airbags, being
side-swiped by something bouncing off the concrete might be more
survivable.

Not being hit by something not bouncing off the Armco is even more
survivable.


Way back when armco was designed, it was selected out of many contenders
because stuff dint bounce off it: It was designed to slice through car
bodywork and introduce friction to bring a vehicle to a safe halt.

Chain link fence was even better, but was rejected on the grounds of
expense.

Armco in short is designed to absorb impact, and decelerate - and not
bounce - vehicles off.




--
Everything you read in newspapers is absolutely true, except for the
rare story of which you happen to have first-hand knowledge. €“ Erwin Knoll

On 09/12/2014 14:54, David Paste wrote:

Viewing footage of the crash site on the BBC news website, it seems that
the concrete barriers (Jersey Barriers?) didn't provide much, if any,
resistance to the vehicles crossing the central reservation. I had
assumed that they would have been at least capable of doing so. Weren't
the metal armco barriers capable of this?

So what is the drive to concrete barriers for? Anyone know?

Cheers.


They will stop cars and glancing blows from lorries but you need a lot
more material to stop a 40 ton lorry.
The best way to design a motorway is to ignore the greens and build the
carriageways 50 yards apart.
The "wasted" space between would be good for wildlife.

"Dennis@home" wrote in message
web.com...
On 09/12/2014 14:54, David Paste wrote:

Viewing footage of the crash site on the BBC news website, it seems that
the concrete barriers (Jersey Barriers?) didn't provide much, if any,
resistance to the vehicles crossing the central reservation. I had
assumed that they would have been at least capable of doing so. Weren't
the metal armco barriers capable of this?

So what is the drive to concrete barriers for? Anyone know?

Cheers.


They will stop cars and glancing blows from lorries but you need a lot
more material to stop a 40 ton lorry.
The best way to design a motorway is to ignore the greens and build the
carriageways 50 yards apart.

The "wasted" space between would be good for wildlife.

For birds, sure, but the other wildlife would get run over getting there.

On 10/12/2014 20:14, Rod Speed wrote:


"Dennis@home" wrote in message
web.com...
On 09/12/2014 14:54, David Paste wrote:

Viewing footage of the crash site on the BBC news website, it seems that
the concrete barriers (Jersey Barriers?) didn't provide much, if any,
resistance to the vehicles crossing the central reservation. I had
assumed that they would have been at least capable of doing so. Weren't
the metal armco barriers capable of this?

So what is the drive to concrete barriers for? Anyone know?

Cheers.


They will stop cars and glancing blows from lorries but you need a lot
more material to stop a 40 ton lorry.
The best way to design a motorway is to ignore the greens and build
the carriageways 50 yards apart.

The "wasted" space between would be good for wildlife.

For birds, sure, but the other wildlife would get run over getting there.

We have been building wildlife tunnels under motorways since the 1970s.

--
Colin Bignell

"Nightjar "cpb"@" "insert my surname here wrote in message
...
On 10/12/2014 20:14, Rod Speed wrote:


"Dennis@home" wrote in message
web.com...
On 09/12/2014 14:54, David Paste wrote:

Viewing footage of the crash site on the BBC news website, it seems
that
the concrete barriers (Jersey Barriers?) didn't provide much, if any,
resistance to the vehicles crossing the central reservation. I had
assumed that they would have been at least capable of doing so. Weren't
the metal armco barriers capable of this?

So what is the drive to concrete barriers for? Anyone know?

Cheers.


They will stop cars and glancing blows from lorries but you need a lot
more material to stop a 40 ton lorry.
The best way to design a motorway is to ignore the greens and build
the carriageways 50 yards apart.

The "wasted" space between would be good for wildlife.

For birds, sure, but the other wildlife would get run over getting there.

We have been building wildlife tunnels under motorways since the 1970s.

Sure, but not to the wasted space between the carriageways
and there is no way to make the walking/slithering wildlife
use them even if you were that stupid.

On 10/12/2014 21:07, Rod Speed wrote:


"Nightjar "cpb"@" "insert my surname here wrote in message
...
On 10/12/2014 20:14, Rod Speed wrote:


"Dennis@home" wrote in message
web.com...
....
They will stop cars and glancing blows from lorries but you need a lot
more material to stop a 40 ton lorry.
The best way to design a motorway is to ignore the greens and build
the carriageways 50 yards apart.

The "wasted" space between would be good for wildlife.

For birds, sure, but the other wildlife would get run over getting
there.

We have been building wildlife tunnels under motorways since the 1970s.

Sure, but not to the wasted space between the carriageways

No need for the space to be wasted, if it is large enough. There is a
working sheep farm in the central reservation of the M62.

and there is no way to make the walking/slithering wildlife
use them even if you were that stupid.

Whatever you may choose to believe, they do use them.

--
Colin Bignell

"Nightjar "cpb"@" "insert my surname here wrote in message
...
On 10/12/2014 21:07, Rod Speed wrote:


"Nightjar "cpb"@" "insert my surname here wrote in message
...
On 10/12/2014 20:14, Rod Speed wrote:


"Dennis@home" wrote in message
web.com...
...
They will stop cars and glancing blows from lorries but you need a lot
more material to stop a 40 ton lorry.
The best way to design a motorway is to ignore the greens and build
the carriageways 50 yards apart.

The "wasted" space between would be good for wildlife.

For birds, sure, but the other wildlife would get run over getting
there.

We have been building wildlife tunnels under motorways since the 1970s.

Sure, but not to the wasted space between the carriageways

No need for the space to be wasted, if it is large enough.

It never is with the situation being discussed.

There is a working sheep farm in the central reservation of the M62.

Different situation entirely to the one where the accident happened.

and there is no way to make the walking/slithering wildlife use them even
if you were that stupid.

Whatever you may choose to believe, they do use them.

Only when you can fence the sides so they have no choice.

On 10/12/2014 23:57, Rod Speed wrote:


"Nightjar "cpb"@" "insert my surname here wrote in message
...
On 10/12/2014 21:07, Rod Speed wrote:
....
"Dennis@home" wrote in message
....
The best way to design a motorway is to ignore the greens and build
the carriageways 50 yards apart.
....
There is a working sheep farm in the central reservation of the M62.

Different situation entirely to the one where the accident happened....

Which was rather the point of Dennis' suggestion; if the central
reservation is wide enough, you won't get any cross-over accidents.

--
Colin Bignell

Nightjar "cpb"@" "insert my surname here wrote
Rod Speed wrote
Nightjar "cpb"@" "insert my surname here wrote
Rod Speed wrote
Dennis@home wrote

The best way to design a motorway is to ignore the
greens and build the carriageways 50 yards apart.

There is a working sheep farm in the central reservation of the M62.

Different situation entirely to the one where the accident happened....

Which was rather the point of Dennis' suggestion;

Like hell it is. It isnt even possible to have a wider separation
between the carriageways large enough to have working
sheep farm where the accident happened.

if the central reservation is wide enough,
you won't get any cross-over accidents.

Duh.

On 11/12/2014 01:50, Rod Speed wrote:
Nightjar "cpb"@" "insert my surname here wrote
Rod Speed wrote
Nightjar "cpb"@" "insert my surname here wrote
Rod Speed wrote
Dennis@home wrote

The best way to design a motorway is to ignore the greens and
build the carriageways 50 yards apart.

There is a working sheep farm in the central reservation of the M62.

Different situation entirely to the one where the accident happened....

Which was rather the point of Dennis' suggestion;

Like hell it is. It isnt even possible to have a wider separation
between the carriageways large enough to have working
sheep farm where the accident happened...

You have totally missed the point. He was talking about how motorways
should be designed, not how that particular one was built.


--
Colin Bignell

On Thu, 11 Dec 2014 09:11:11 +0000, Nightjar \"cpb\"@ wrote:

The best way to design a motorway is to ignore the greens and
build the carriageways 50 yards apart.

There is a working sheep farm in the central reservation of the M62.

Different situation entirely to the one where the accident
happened....

Which was rather the point of Dennis' suggestion;

Like hell it is. It isnt even possible to have a wider separation
between the carriageways large enough to have working sheep farm where
the accident happened...

You have totally missed the point. He was talking about how motorways
should be designed, not how that particular one was built.

If the Highways Agency bought enough land up, there could be enough
central reservation to put as much width as you like between the
carriageways...

Doing so on oooh, plucks random motorway from air the M25 might be tad
problematic, politically, especially given that many stretchs CANNOT be
widened any further without compulsory purchase of quite a few rather
expensive houses.

Nightjar "cpb"@" "insert my surname here wrote
Rod Speed wrote
Nightjar "cpb"@" "insert my surname here wrote
Rod Speed wrote
Nightjar "cpb"@" "insert my surname here wrote
Rod Speed wrote
Dennis@home wrote

The best way to design a motorway is to ignore the greens and
build the carriageways 50 yards apart.

There is a working sheep farm in the central reservation of the M62.

Different situation entirely to the one where the accident happened....

Which was rather the point of Dennis' suggestion;

Like hell it is. It isnt even possible to have a wider separation
between the carriageways large enough to have working
sheep farm where the accident happened...

You have totally missed the point.

Bull****.

He was talking about how motorways should be designed,

He wasn’t proposing that they be done like that.

not how that particular one was built.

That is a situation where separating the carriageways by
so much that its possible to have a full working sheep farm
between them is so rare that it isnt practical very often at all.

"Adrian" wrote in message
...
On Thu, 11 Dec 2014 09:11:11 +0000, Nightjar \"cpb\"@ wrote:

The best way to design a motorway is to ignore the greens and
build the carriageways 50 yards apart.

There is a working sheep farm in the central reservation of the M62.

Different situation entirely to the one where the accident
happened....

Which was rather the point of Dennis' suggestion;

Like hell it is. It isnt even possible to have a wider separation
between the carriageways large enough to have working sheep farm where
the accident happened...

You have totally missed the point. He was talking about how motorways
should be designed, not how that particular one was built.

If the Highways Agency bought enough land up, there could be enough
central reservation to put as much width as you like between the
carriageways...

Its just not feasible in most situations.

Doing so on oooh, plucks random motorway from air the M25
might be tad problematic, politically, especially given that many
stretchs CANNOT be widened any further without compulsory
purchase of quite a few rather expensive houses.

Precisely.

In article , Brian Gaff
wrote:
Wrecking more cars so they can sell new ones? I'd imagine
the cheaper the barriers can be built the better. However
the ones you mention which used to be the norm give and
buckle to absorb the energy, Concrete does not it seems.

Brian
Repair /replacement of metal barriers isn't cheap or
convenient either. - close a lane in each direction for
several hours with a team taking several hours to do the
work following even a minor incident.

I see the concrete barriers on the N340 (Med coast road) has
eveidence of many many collisions and doesn't (usually) need
remedial work

John

--
John Mulrooney
NOTE Email address IS correct but might not be checked for a while.

Give a man a fish and he will eat for a day. Teach him how to fish, and he will sit in a boat drink beer all day.

On 11/12/2014 09:19, Adrian wrote:
....
If the Highways Agency bought enough land up, there could be enough
central reservation to put as much width as you like between the
carriageways...

Put them far enough apart and they don't need to own the land between
the carriageways, as with the sheep farm in the M62 central reservation.

Doing so on oooh, plucks random motorway from air the M25 might be tad
problematic, politically, especially given that many stretchs CANNOT be
widened any further without compulsory purchase of quite a few rather
expensive houses.

The point is you don't need to widen the existing motorway. Follow the
concept of the original Ringways scheme and build another ring motorway
well outside it. However, instead of having them as two-way motorways,
use the full width of the existing M25 for traffic travelling in one
direction and build the new motorway just as wide, for traffic
travelling in the other direction. The existing M25 could even be kept
as two separate carriageways, both travelling in the same direction, but
with limited access to one carriageway, so that long distance through
traffic does not need to mix with local commuter traffic.

--
Colin Bignell

On Thursday, December 11, 2014 11:45:08 AM UTC, JTM wrote:
In article , Brian Gaff
wrote:
Wrecking more cars so they can sell new ones? I'd imagine
the cheaper the barriers can be built the better. However
the ones you mention which used to be the norm give and
buckle to absorb the energy, Concrete does not it seems.

Brian
Repair /replacement of metal barriers isn't cheap or
convenient either. - close a lane in each direction for
several hours with a team taking several hours to do the
work following even a minor incident.

I see the concrete barriers on the N340 (Med coast road) has
eveidence of many many collisions and doesn't (usually) need
remedial work

John

--
John Mulrooney
NOTE Email address IS correct but might not be checked for a while.

Give a man a fish and he will eat for a day. Teach him how to fish, and he will sit in a boat drink beer all day.

Not sure on the comparable cost/time of replacement but metal barriers always seem to be replaced pretty quickly whereas the currently damaged concrete M25 barrier is still not repaired after three days. Not sure when it's scheduled but with "40m" needing repair and "time for concrete to set" being required total disruption time seems a lot higher for damaged concrete barriers.

Nightjar "cpb"@" "insert my surname here wrote
Adrian wrote

If the Highways Agency bought enough land up,
there could be enough central reservation to put
as much width as you like between the carriageways...

Put them far enough apart and they don't need to own the land between
the carriageways, as with the sheep farm in the M62 central reservation.

There's a reason that hardly any are done like that.

Doing so on oooh, plucks random motorway from air the M25
might be tad problematic, politically, especially given that many
stretchs CANNOT be widened any further without compulsory
purchase of quite a few rather expensive houses.

The point is you don't need to widen the existing motorway. Follow
the concept of the original Ringways scheme and build another ring
motorway well outside it. However, instead of having them as two-way
motorways, use the full width of the existing M25 for traffic travelling
in one direction and build the new motorway just as wide, for traffic
travelling in the other direction.

There's a reason that hardly any are done like that.

The existing M25 could even be kept as two separate carriageways,
both travelling in the same direction, but with limited access to one
carriageway, so that long distance through traffic does not need to
mix with local commuter traffic.

There's a reason that hardly any are done like that.

In message . com,
"Dennis@home" writes
On 09/12/2014 14:54, David Paste wrote:

Viewing footage of the crash site on the BBC news website, it seems that
the concrete barriers (Jersey Barriers?) didn't provide much, if any,
resistance to the vehicles crossing the central reservation. I had
assumed that they would have been at least capable of doing so. Weren't
the metal armco barriers capable of this?

So what is the drive to concrete barriers for? Anyone know?

Cheers.


They will stop cars and glancing blows from lorries but you need a lot
more material to stop a 40 ton lorry.
The best way to design a motorway is to ignore the greens and build the
carriageways 50 yards apart.
The "wasted" space between would be good for wildlife.
You could always put a high speed train up the middle
--
bert

On Tue, 09 Dec 2014 21:13:47 +0000, newshound
wrote:


From the third photo here

http://www.bbc.co.uk/news/uk-england-essex-30391284

it looks as though they are simple gravity structures, not tied down to
the ground at all.

That's strange because I thought they were anchored by 24mm rebar. The
reason being in the 80s a welsh engineering firm that built forestry
harvesters had developed a device using compressed air for firing such
rods 7 metres into the ground and installing crash barriers was one of
the jobs touted. The other one was doing the same with well point
tubes to collect gas from landfill.

The base projector was allegedly surplus from a soft launch system
from Porton Down.

AJH

On Friday, December 12, 2014 8:17:04 PM UTC, bert wrote:
In message . com,
"Dennis@home" writes
On 09/12/2014 14:54, David Paste wrote:

Viewing footage of the crash site on the BBC news website, it seems that
the concrete barriers (Jersey Barriers?) didn't provide much, if any,
resistance to the vehicles crossing the central reservation. I had
assumed that they would have been at least capable of doing so. Weren't
the metal armco barriers capable of this?

So what is the drive to concrete barriers for? Anyone know?

Cheers.


They will stop cars and glancing blows from lorries but you need a lot
more material to stop a 40 ton lorry.
The best way to design a motorway is to ignore the greens and build the
carriageways 50 yards apart.
The "wasted" space between would be good for wildlife.
You could always put a high speed train up the middle

A goods train might make better economic sense. Perhaps design it to take truck trailers whole.


NT

wrote in message
...
On Friday, December 12, 2014 8:17:04 PM UTC, bert wrote:
In message . com,
"Dennis@home" writes
On 09/12/2014 14:54, David Paste wrote:

Viewing footage of the crash site on the BBC news website, it seems
that
the concrete barriers (Jersey Barriers?) didn't provide much, if any,
resistance to the vehicles crossing the central reservation. I had
assumed that they would have been at least capable of doing so.
Weren't
the metal armco barriers capable of this?

So what is the drive to concrete barriers for? Anyone know?

Cheers.


They will stop cars and glancing blows from lorries but you need a lot
more material to stop a 40 ton lorry.
The best way to design a motorway is to ignore the greens and build the
carriageways 50 yards apart.
The "wasted" space between would be good for wildlife.
You could always put a high speed train up the middle

A goods train might make better economic sense.

I doubt it given the immense cost of something
more sophisticated than level crossings.

Perhaps design it to take truck trailers whole.

That's unlikely to be viable in a place as small as that soggy little
island.