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Posted to uk.d-i-y
Tim Downie
 
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Default Fixing a roof truss

Hmm.. how would you fix this?

http://www.zen31010.zen.co.uk/images/1.jpg

It looks like the wooden beams were just glued into the metal parts without
any through-bolting. Given their differences in expansion coefficients,
seems a bit dodgy to me. What would have happened if one of the joints at
the top had given way?

Tim


  #2   Report Post  
Posted to uk.d-i-y
Alistair Riddell
 
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Default Fixing a roof truss

On Fri, 3 Mar 2006, Tim Downie wrote:

Hmm.. how would you fix this?

http://www.zen31010.zen.co.uk/images/1.jpg

It looks like the wooden beams were just glued into the metal parts without
any through-bolting. Given their differences in expansion coefficients,
seems a bit dodgy to me. What would have happened if one of the joints at
the top had given way?


I get a 404 not found at that URL.

You aren't perhaps talking about the Scottish "Parliament" are you?!

--
Alistair Riddell - BOFH
Microsoft - because god hates us
  #3   Report Post  
Posted to uk.d-i-y
Andrew Gabriel
 
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Default Fixing a roof truss

In article ,
"Tim Downie" writes:
Hmm.. how would you fix this?

http://www.zen31010.zen.co.uk/images/1.jpg


Well, you could fix it by either uploading an image to that
URL, or saying where the image really is.

--
Andrew Gabriel
  #4   Report Post  
Posted to uk.d-i-y
S Viemeister
 
Posts: n/a
Default Fixing a roof truss

Alistair Riddell wrote:

On Fri, 3 Mar 2006, Tim Downie wrote:

Hmm.. how would you fix this?

http://www.zen31010.zen.co.uk/images/1.jpg

It looks like the wooden beams were just glued into the metal parts without
any through-bolting. Given their differences in expansion coefficients,
seems a bit dodgy to me. What would have happened if one of the joints at
the top had given way?


I get a 404 not found at that URL.

You aren't perhaps talking about the Scottish "Parliament" are you?!

It certainly sounds like that. I was amazed when I saw the photos - I had
assumed that the beams would be held by more than just their tapered shape,
and glue, but there was no sign of a bolt.
  #5   Report Post  
Posted to uk.d-i-y
 
Posts: n/a
Default Fixing a roof truss


Andrew Gabriel wrote:
In article ,
"Tim Downie" writes:
Hmm.. how would you fix this?

http://www.zen31010.zen.co.uk/images/1.jpg


Well, you could fix it by either uploading an image to that
URL, or saying where the image really is.

--
Andrew Gabriel


Oh b*gger! Should have been
http://www.zen31010.zen.co.uk/images/1.jpeg

(Yes, it is the Scottish paliament)

Tim



  #6   Report Post  
Posted to uk.d-i-y
The Natural Philosopher
 
Posts: n/a
Default Fixing a roof truss

S Viemeister wrote:
Alistair Riddell wrote:
On Fri, 3 Mar 2006, Tim Downie wrote:

Hmm.. how would you fix this?

http://www.zen31010.zen.co.uk/images/1.jpg

It looks like the wooden beams were just glued into the metal parts without
any through-bolting. Given their differences in expansion coefficients,
seems a bit dodgy to me. What would have happened if one of the joints at
the top had given way?

I get a 404 not found at that URL.

You aren't perhaps talking about the Scottish "Parliament" are you?!

It certainly sounds like that. I was amazed when I saw the photos - I had
assumed that the beams would be held by more than just their tapered shape,
and glue, but there was no sign of a bolt.


All the joints are in compression, so no need to cope with any shear
force at all.

Probably don;t even need teh glue.

A reasonable flexible polyurethane glue should be entirely adequate.
BUT what a complete load of old ******** that structure is. Obviously
designed by architects and structural engineers with too much time and
public money to spend. Its engineering for the sake of it. Not for any
PURPOSE.


  #7   Report Post  
Posted to uk.d-i-y
 
Posts: n/a
Default Fixing a roof truss


The Natural Philosopher wrote:
S Viemeister wrote:


It certainly sounds like that. I was amazed when I saw the photos - I had
assumed that the beams would be held by more than just their tapered shape,
and glue, but there was no sign of a bolt.


All the joints are in compression, so no need to cope with any shear
force at all.


Don't you mean "All the joints *should* be in compression". If it had
been in compression it's hard to see how it could have come undone.

I think if the metal tie bars that run across beneath the joints have
stretched or are insufficiently tensioned, then the joint could
potentially be in tension.

Probably don;t even need teh glue.

A reasonable flexible polyurethane glue should be entirely adequate.


But demonstrably not in this case.

Tim

  #8   Report Post  
Posted to uk.d-i-y
Roger Mills \(aka Set Square\)
 
Posts: n/a
Default Fixing a roof truss

In an earlier contribution to this discussion,
S Viemeister wrote:

Alistair Riddell wrote:

On Fri, 3 Mar 2006, Tim Downie wrote:

Hmm.. how would you fix this?

http://www.zen31010.zen.co.uk/images/1.jpg

It looks like the wooden beams were just glued into the metal parts
without any through-bolting. Given their differences in expansion
coefficients, seems a bit dodgy to me. What would have happened if
one of the joints at the top had given way?


I get a 404 not found at that URL.

You aren't perhaps talking about the Scottish "Parliament" are you?!

It certainly sounds like that. I was amazed when I saw the photos -
I had assumed that the beams would be held by more than just their
tapered shape, and glue, but there was no sign of a bolt.


I'm not so sure about any glue! I reckon the "designers" relied on the
wooden beams always being in compression, and thus holding themselves
together. Seems they were wrong!
--
Cheers,
Roger
______
Please reply to newsgroup.
Reply address IS valid, but is disposable in the event of excessive
spam.


  #9   Report Post  
Posted to uk.d-i-y
 
Posts: n/a
Default Fixing a roof truss


The Natural Philosopher wrote:
S Viemeister wrote:
Alistair Riddell wrote:
On Fri, 3 Mar 2006, Tim Downie wrote:

Hmm.. how would you fix this?

http://www.zen31010.zen.co.uk/images/1.jpg

It looks like the wooden beams were just glued into the metal parts without
any through-bolting. Given their differences in expansion coefficients,
seems a bit dodgy to me. What would have happened if one of the joints at
the top had given way?
I get a 404 not found at that URL.

You aren't perhaps talking about the Scottish "Parliament" are you?!

It certainly sounds like that. I was amazed when I saw the photos - I had
assumed that the beams would be held by more than just their tapered shape,
and glue, but there was no sign of a bolt.


All the joints are in compression, so no need to cope with any shear
force at all.

Probably don;t even need teh glue.

A reasonable flexible polyurethane glue should be entirely adequate.
BUT what a complete load of old ******** that structure is. Obviously
designed by architects and structural engineers with too much time and
public money to spend. Its engineering for the sake of it. Not for any
PURPOSE.


The architect is dead but was known as "el collapso" after the roof of
a building he designed in his native Spain collapsed. Apperently the
builders were at fault that time but I see a pattern forming...

MBQ

  #15   Report Post  
Posted to uk.d-i-y
S Viemeister
 
Posts: n/a
Default Fixing a roof truss

"Roger Mills (aka Set Square)" wrote:

Is he dead because the previous building collapsed on *him*?

I believe it was a brain tumour of some sort. He died before the building
was anywhere near complete.


  #16   Report Post  
Posted to uk.d-i-y
Brian Sharrock
 
Posts: n/a
Default Fixing a roof truss


wrote in message
oups.com...

The Natural Philosopher wrote:
S Viemeister wrote:
Alistair Riddell wrote:
On Fri, 3 Mar 2006, Tim Downie wrote:

Hmm.. how would you fix this?

http://www.zen31010.zen.co.uk/images/1.jpg

It looks like the wooden beams were just glued into the metal parts
without
any through-bolting. Given their differences in expansion
coefficients,
seems a bit dodgy to me. What would have happened if one of the
joints at
the top had given way?
I get a 404 not found at that URL.

You aren't perhaps talking about the Scottish "Parliament" are you?!

It certainly sounds like that. I was amazed when I saw the photos - I
had
assumed that the beams would be held by more than just their tapered
shape,
and glue, but there was no sign of a bolt.


All the joints are in compression, so no need to cope with any shear
force at all.


According to today's 'Telegraph (so it must be true ...) the oddly shaped
beams were 'reminiscent' of the Fife Oak beams in the original Scottish
Parliament building .... that'd be the one they used before the Scottish
King took over the English (&Wales) throne and the Scottish parliament voted
to disband itself and be over-repreented in the Westminster place. {BTW: the
exchange rate between the Scottish Pound and the English Pound was adjusted
too - rather like the 'Ost'Mark and the 'Deutchmark'}.
One can only presume that it was all the hot air from the MSPs that
displaced the beam.I mean; surely the have Building Control Officers in
Edingburgh? [One knows they didn't count the bawbees ... but !]

--

Brian



Probably don;t even need teh glue.

A reasonable flexible polyurethane glue should be entirely adequate.
BUT what a complete load of old ******** that structure is. Obviously
designed by architects and structural engineers with too much time and
public money to spend. Its engineering for the sake of it. Not for any
PURPOSE.


The architect is dead but was known as "el collapso" after the roof of
a building he designed in his native Spain collapsed. Apperently the
builders were at fault that time but I see a pattern forming...

MBQ



  #17   Report Post  
Posted to uk.d-i-y
Ed Sirett
 
Posts: n/a
Default Fixing a roof truss

On Fri, 03 Mar 2006 08:54:01 -0500, S Viemeister wrote:

Alistair Riddell wrote:

On Fri, 3 Mar 2006, Tim Downie wrote:

Hmm.. how would you fix this?

http://www.zen31010.zen.co.uk/images/1.jpg

It looks like the wooden beams were just glued into the metal parts without
any through-bolting. Given their differences in expansion coefficients,
seems a bit dodgy to me. What would have happened if one of the joints at
the top had given way?


I get a 404 not found at that URL.

You aren't perhaps talking about the Scottish "Parliament" are you?!

It certainly sounds like that. I was amazed when I saw the photos - I had
assumed that the beams would be held by more than just their tapered shape,
and glue, but there was no sign of a bolt.


My guess is that for some reason that strut was in tension when it shoudl
have been in compression.

Perhaps it was a little short.
Perhaps the tie bars below are not in enough tension keep it in
comrpession.

Wild guess mode:
If I had to be responsible for fixing it I'd slacken the tie bars a
little. Replace the strut with a thickness or two of card to 'shim it
out'. Then tighten the tie rods to bring it into compression.





--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html


  #18   Report Post  
Posted to uk.d-i-y
S Viemeister
 
Posts: n/a
Default Fixing a roof truss

Brian Sharrock wrote:

One can only presume that it was all the hot air from the MSPs that
displaced the beam.

Well, it WAS right over the Conservative benches.........
  #19   Report Post  
Posted to uk.d-i-y
Ophelia
 
Posts: n/a
Default Fixing a roof truss


"S Viemeister" wrote in message
...
Alistair Riddell wrote:

On Fri, 3 Mar 2006, Tim Downie wrote:

Hmm.. how would you fix this?

http://www.zen31010.zen.co.uk/images/1.jpg

It looks like the wooden beams were just glued into the metal parts
without
any through-bolting. Given their differences in expansion
coefficients,
seems a bit dodgy to me. What would have happened if one of the
joints at
the top had given way?


I get a 404 not found at that URL.

You aren't perhaps talking about the Scottish "Parliament" are you?!

It certainly sounds like that. I was amazed when I saw the photos - I
had
assumed that the beams would be held by more than just their tapered
shape,
and glue, but there was no sign of a bolt.


They spent a fortune of our money on that heap of junk


  #20   Report Post  
Posted to uk.d-i-y
Ophelia
 
Posts: n/a
Default Fixing a roof truss


"S Viemeister" wrote in message
...
Brian Sharrock wrote:

One can only presume that it was all the hot air from the MSPs that
displaced the beam.

Well, it WAS right over the Conservative benches.........


LOL




  #21   Report Post  
Posted to uk.d-i-y
Tim Downie
 
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Default Fixing a roof truss

S Viemeister wrote:
Alistair Riddell wrote:

You aren't perhaps talking about the Scottish "Parliament" are you?!

It certainly sounds like that. I was amazed when I saw the photos -
I had assumed that the beams would be held by more than just their
tapered shape, and glue, but there was no sign of a bolt.


Does anyone see how this story
http://www.theherald.co.uk/politics/57828.html can fit in any way with this
image http://www.zen31010.zen.co.uk/images/1.jpeg?

Not only can't you see any bolts, you can't see any bolt holes in the free
end of the beam.

I'm puzzled.

Tim


  #22   Report Post  
Posted to uk.d-i-y
Guy King
 
Posts: n/a
Default Fixing a roof truss

The message
from "Tim Downie" contains these words:

Not only can't you see any bolts, you can't see any bolt holes in the free
end of the beam.


I'm puzzled.


It looks like all the wood is always supposed to be in compression.
Those metal tension rods will be pulling up on the bottom of each group
of struts. In theory fine but obviously the designer had more
familiarity with theory than real life.

I'd suspect that though it should have worked nicely the tolerances
involved are such that any uneven contraction in the wood would leave
one strut under much lss compression than the others - enough to slip
sidways out of the jaws intended to hold it.

I'll bet it happens again soon, too. They'll probably end up putting a
coachscrew in from each face on each strut to retain it in situations
when the load's not behaving itself.

--
Skipweasel
Pay no attention to the man behind the curtain.
  #23   Report Post  
Posted to uk.d-i-y
Tim Downie
 
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Default Fixing a roof truss

Guy King wrote:
The message
from "Tim Downie" contains these
words:

Not only can't you see any bolts, you can't see any bolt holes in
the free end of the beam.


I'm puzzled.


It looks like all the wood is always supposed to be in compression.
Those metal tension rods will be pulling up on the bottom of each
group
of struts. In theory fine but obviously the designer had more
familiarity with theory than real life.

I'd suspect that though it should have worked nicely the tolerances
involved are such that any uneven contraction in the wood would leave
one strut under much lss compression than the others - enough to slip
sidways out of the jaws intended to hold it.


That's exactly the theory that was touted in the papers last week but...

I'll bet it happens again soon, too. They'll probably end up putting a
coachscrew in from each face on each strut to retain it in situations
when the load's not behaving itself.


....the story in the papers today is that it was a missing bolt (one of two)
that caused the problem. My puzzlement is over the fact that it looks like
there never were *any* bolts, so how can one be missing?

Tim


  #24   Report Post  
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Roger
 
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Default Fixing a roof truss

The message
from "Tim Downie" contains these words:

It certainly sounds like that. I was amazed when I saw the photos -
I had assumed that the beams would be held by more than just their
tapered shape, and glue, but there was no sign of a bolt.


Does anyone see how this story
http://www.theherald.co.uk/politics/57828.html can fit in any way with this
image http://www.zen31010.zen.co.uk/images/1.jpeg?


Not only can't you see any bolts, you can't see any bolt holes in the free
end of the beam.


It could have been an interference fit in the shoe but it seems more
than a little careless to design something that will come apart like
that. Or even to design something that on the face of it is a
substantial strut but which must have attempting to be a tie when it
came apart.

I'm puzzled.


So am I. Does any of the gubbins (TM) in the roof serve any purpose
other than to have added to the grotesque overspend?

--
Roger Chapman
  #25   Report Post  
Posted to uk.d-i-y
Roger Mills \(aka Set Square\)
 
Posts: n/a
Default Fixing a roof truss

In an earlier contribution to this discussion,
Roger wrote:


So am I. Does any of the gubbins (TM) in the roof serve any purpose
other than to have added to the grotesque overspend?


Presumably not, if it couldn't even hold itself - let alone anything else -
up!
--
Cheers,
Roger
______
Please reply to newsgroup.
Reply address IS valid, but is disposable in the event of excessive
spam.




  #26   Report Post  
Posted to uk.d-i-y
Terry
 
Posts: n/a
Default Fixing a roof truss


"Roger Mills (aka Set Square)" wrote in message
...
In an earlier contribution to this discussion,
Roger wrote:


So am I. Does any of the gubbins (TM) in the roof serve any purpose
other than to have added to the grotesque overspend?


Presumably not, if it couldn't even hold itself - let alone anything
else - up!
--
Cheers,
Roger
__________________________________________________ _____

Agree. Seems typical of these 'Too bl**dy clever by half ' architectural
'masterpieces'!
Marginally or riskily engineered, maybe, if the loss of a single bolt is
crucial?
Anyway; with temps rising above freezing, must go and clear some snow off
the roof of this wood trussed house. Not sure what snow load the trusses
were engineered for, 36 years ago when I and two carpenters built it!
So far, at least, the roof hasn't blown away or shown any signs whatever of
caving in, in a climate very similar to say, Scotland! i.e. occasional snow
load three times in 36 years.
But then of course this roof is just a plain old wood trussed, lumber roof
built in much the same method used here for the last several hundreds of
years.


  #27   Report Post  
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Grimly Curmudgeon
 
Posts: n/a
Default Fixing a roof truss

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Tim Downie"
saying something like:

S Viemeister wrote:
Alistair Riddell wrote:

You aren't perhaps talking about the Scottish "Parliament" are you?!

It certainly sounds like that. I was amazed when I saw the photos -
I had assumed that the beams would be held by more than just their
tapered shape, and glue, but there was no sign of a bolt.


Does anyone see how this story
http://www.theherald.co.uk/politics/57828.html can fit in any way with this


"Around 3in long, similar "socket head cap screw" bolts can be bought on
the internet for 1.50."

Humph. I'll bet the actual charge was a tenner a bolt.

--

Dave
  #28   Report Post  
Posted to uk.d-i-y
Guy King
 
Posts: n/a
Default Fixing a roof truss

The message
from Grimly Curmudgeon contains
these words:

Humph. I'll bet the actual charge was a tenner a bolt.


And the fuss about fixing it. Before all these stupid rules someone
would have just arrived with a ladder and run up it and screwed it back
into place.

--
Skipweasel
Pay no attention to the man behind the curtain.
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