OT The Forth Bridge

tim..... wrote:

"Chris Hogg" wrote in message
...
On Fri, 4 Dec 2015 18:44:40 -0500, S Viemeister
wrote:

On 12/4/2015 3:09 PM, Roderick Stewart wrote:

I'm sure they'll manage without it for a while. I remember using the
ferry on the way to our holidays before there was a bridge, and still
have a few seconds of 9.5mm movie film of it partially built.

Have they reinstituted the ferry?

Ceefax said they were thinking about it. But it won't be able to carry
anything like the traffic that the bridge did.

There were hour-long queues to use it in the 50s when "normal" roads ran
virtually empty

that's why they built the bridge

It doesn't have a hope of being a useful replacement

tim





They should just sling out a long pontoon bridge across the Forth. ;-)

In article ,
Martin wrote:
On Sat, 05 Dec 2015 08:31:02 +0000 (GMT), charles
wrote:

In article ,
Chris Hogg wrote:
On Fri, 4 Dec 2015 18:44:40 -0500, S Viemeister
wrote:

On 12/4/2015 3:09 PM, Roderick Stewart wrote:

I'm sure they'll manage without it for a while. I remember using
the ferry on the way to our holidays before there was a bridge, and
still have a few seconds of 9.5mm movie film of it partially built.

Have they reinstituted the ferry?

Ceefax said they were thinking about it. But it won't be able to carry
anything like the traffic that the bridge did.

It will probably take a year or so to build suitable boats.

Believe it or not there are unused surplus car ferries available.

Car ferries for 1hr plus crossings take so long to load and unload. Where
would they dock? A Rosyth to Leith ferry route might work, but it would
probably end up as a 2+ hour journey.

--
Please note new email address:

On Sat, 05 Dec 2015 13:11:19 +0000, Graham Murray
wrote:

Bill Wright writes:

I think they're over reacting! Just because of a few cracks in the
metalwork they've closed the bridge.

Where are the Royal Engineers when you need them? If it been a war and
a bridge was blown up by the enemy to stop the tanks and troops
crossing, the Royal Engineers could have constructed a Bailey (or other
type of) Bridge in a couple of days

I very much doubt it. The Forth Road Bridge is 2.5 km long. That length
would require many Bailey bridge trusses with many vertical piers
supporting them. The piers would need to be built on foundations on the
river bed. The alternative would be to use floating pontoons to support
the trusses (spans). That would be a very far from trivial engineering
task.

Each Bailey truss is up to 60 metres long. So unless modern ones are
longer that would mean up to 42 trusses supported by 41 piers and/or
pontoons.

As far as I know Bailey Bridges were never used to bridge such a wide
stretch of river/estuary.

According to this:
https://en.wikipedia.org/wiki/Bailey...Bailey_bridges

Modern Bailey bridges

Bailey bridges are in regular use throughout the world in the 21st
century. Some exceptional examples include:

The longest Bailey bridge was put into service in October 1975.
This 788 metres (2,585 ft), two-lane bridge crossed the Derwent
River at Hobart, Australia. It was opened around a year after
the Tasman Bridge disaster destroyed the only river crossing and
effectively divided the city in two.

788 metres is a bit less than a third of the length of the Forth Road
Bridge.

Any temporary replacement for the existing bridge would need *not* to
block boats and ships going up and down the river. That would include
vessels to and from the Rosyth Dockyard.

--
Peter Duncanson
(in uk.tech.digital-tv)

On Sat, 05 Dec 2015 09:36:38 +0000, Chris J Dixon
wrote:

Tim Watts wrote:

On 04/12/15 18:16, Peter Duncanson wrote:
It looks like a job for No More Nails.

No - definitely ali mesh and some structural Isopon - kept my Maxi
passing MOTs even after most of the door bottoms and sills had disappeared.

http://www.nedmartin.org/v3/amused/e...ge-repair-team

Chris

smile

--
Peter Duncanson
(in uk.tech.digital-tv)

On 05/12/2015 08:12, Tim Watts wrote:
On 04/12/15 18:16, Peter Duncanson wrote:
It looks like a job for No More Nails.

No - definitely ali mesh and some structural Isopon - kept my Maxi
passing MOTs even after most of the door bottoms and sills had disappeared.


I once had a new windscreen fitted by the insurance and the guy said
there wasn't really enough metal left to fit it to. But he did it, I
added some parcel tape and aerosol paint, and it passed the MOT.

Bill

On 05/12/2015 08:31, charles wrote:

It will probably take a year or so to build suitable boats.

ebay.

Bill

On 05/12/2015 09:41, Martin wrote:

Believe it or not there are unused surplus car ferries available.


Give McBraynes a ring.

Bill

Bill Wright wrote:
On 05/12/2015 09:41, Martin wrote:

Believe it or not there are unused surplus car ferries available.


Give McBraynes a ring.

Bill


Can't see any ferry service providing useful level of transport for that
route. Wouldn't surprised me if they give up on the idea.

Tim

On 05/12/15 11:12, lid wrote:
On Sat, 5 Dec 2015 08:14:08 +0000, Tim Watts
wrote:

On 04/12/15 19:16, Mike Tomlinson wrote:
En el artículo , Bill Wright
escribió:

I think they're over reacting! Just because of a few cracks in the
metalwork they've closed the bridge.

It's not that, individual strands of cable are snapping in the main
stays (the horizontal runs that span the bridge). Because snapped
strands are hard to detect, they can't tell how many have gone.

The problem is caused by the Scottish weather - the cables are corroding
and snapping on the inside. Eventually, you're going to have the outer
(painted, protected) cable with a rotten core.

There's supposedly a proposal in place to blow low-humidity air into the
gaps in the cable to reduce the speed of corrosion but I haven't been
able to find out more. I have a feeling it's too late to save the
bridge now.


Steel ropes used for offshore work were packed with grease during
assembly - I wonder if these were originally?

So are cables supporting TV masts, and the grease has to be reapplied
at intervals.


I have it on good authority that once the grease have come out of the
core, it's impossible to adequately apply more - even immersing the rope
in heated liquid grease is not enough[1]. However, I suppose applying
more outside may stop the inside grease washing/leeching out.

[1] Reading Uni Mech Eng dept, specialist in wire ropes.

On 05/12/2015 22:22, Tim Watts wrote:
On 05/12/15 11:12, lid wrote:
On Sat, 5 Dec 2015 08:14:08 +0000, Tim Watts
wrote:

On 04/12/15 19:16, Mike Tomlinson wrote:
En el artículo , Bill Wright
escribió:

I think they're over reacting! Just because of a few cracks in the
metalwork they've closed the bridge.

It's not that, individual strands of cable are snapping in the main
stays (the horizontal runs that span the bridge). Because snapped
strands are hard to detect, they can't tell how many have gone.

The problem is caused by the Scottish weather - the cables are
corroding
and snapping on the inside. Eventually, you're going to have the outer
(painted, protected) cable with a rotten core.

There's supposedly a proposal in place to blow low-humidity air into
the
gaps in the cable to reduce the speed of corrosion but I haven't been
able to find out more. I have a feeling it's too late to save the
bridge now.


Steel ropes used for offshore work were packed with grease during
assembly - I wonder if these were originally?

So are cables supporting TV masts, and the grease has to be reapplied
at intervals.


I have it on good authority that once the grease have come out of the
core, it's impossible to adequately apply more - even immersing the rope
in heated liquid grease is not enough[1]. However, I suppose applying
more outside may stop the inside grease washing/leeching out.

[1] Reading Uni Mech Eng dept, specialist in wire ropes.

But they can dehumidify them...

http://www.bbc.co.uk/news/uk-scotlan...-fife-21522376

And the cables aren't wire ropes, so far as I can tell. More parallel
bundles. But I could be wrong.

https://en.wikipedia.org/wiki/Forth_...ge_Chamber.jpg

--
Rod