OT The Forth Bridge

Mike Tomlinson wrote:
En el artÃ*culo , Tim+
escribió:

What have the cables got to do with the current problem? Nothing!

Jesus.

Everything. It's a 50 year old bridge which has carried far beyond its
designed amount of traffic for many years and now is showing signs of
its age and workload. In other words, it's almost worn out.

Ever heard of context?


Yes, but you said that the bridge was closed because of snapping cable
strands. Whilst indirectly that may be related, that is not the reason the
bridge was closed.

Tim

On 05/12/2015 10:11, Martin wrote:

They could sell it to the USA to bridge the Grand Canyon.

As long as it's not held together with metric nuts and bolts ?



--
Mark
Please replace invalid and invalid with gmx and net to reply.

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.

On Sat, 05 Dec 2015 10:35:42 +0100, Martin wrote:

No it's the First Forth Road Bridge.

But it's the Second Forth Bridge.

Sounds like the answer to a riddle: "What can be described as first,
second or Fo[u]rth but not third?". (You'd have to ask it out loud
because of the spelling).

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.

Nowadays it is partially falling to pieces.
Using microphones attached to the supporting cables they can hear the individual
wires, that make up the cables, snapping

And yet the Brooklyn bridge is still standing, and has been standing a
lot longer, despite some of the strands in its cables having been made
from substandard steel (thanks to dishonest suppliers). They say it
was "overdesigned" to allow for a certain mumber of breakages. Don't
we do this any more?

Rod.

In article ,
"Dave Plowman (News)" writes:
In article ,
Brian-Gaff wrote:
I do often wonder about more modern bridgees and exactly how long they
might be expected to last. The old Severn Bridge has had to have
significant work done to it to keep it safe after all.

Very true. I went on a school trip to see the Forth Road bridge being
built. Seems odd it has had such a short life.

It looks like it will last almost exactly half its original design
life of 120 years, assuming they manage to get this problem repaired,
and less if they decide to give up on it a few years early.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

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

On Sat, 05 Dec 2015 11:30:12 +0000, Roderick Stewart
wrote:

And yet the Brooklyn bridge is still standing, and has been standing a
lot longer, despite some of the strands in its cables having been made
from substandard steel (thanks to dishonest suppliers). They say it
was "overdesigned" to allow for a certain mumber of breakages. Don't
we do this any more?

No, the clueless bean-counters have filtered out that sort of 'gross
inefficiency'.

"Graham Murray" wrote in message
...
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

but elf and safety would forbid anybody from actually using it

tim

There have been some daft suggestions on repair methods. There is only one
way - some Dexion and self tapping screws - but make sure suitable sized
washer are used so that the screw heads don't pull through the Dexion.
Finish off with Hammerite to keep the damp out.

"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