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stuving
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« on: October 19, 2016, 12:58:37 » |
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From the BBC» : Investigation after Manchester Victoria Station roof tearA new roof at Manchester's Victoria Station that had a panel cave in, injuring two people, is being inspected as an investigation gets under way. The panel tore above Platforms 1 and 2 on Tuesday afternoon amid heavy rain. Witnesses said "gallons of water" fell on people standing on a platform. Two people suffered minor head injuries. The station remains open with services running normally and a full roof inspection is under way, Northern Rail said on Wednesday.  The damage caused by heavy rain to the roofContractors for Northern Rail have secured the roof panels that were damaged but the area below remains cordoned off. The main concourse, which was sealed off over fears other parts of the roof could collapse, has now reopened a spokesperson for Northern said. The station underwent a £44m upgrade last year, which included the new roof. The 15,000 square metre roof was added as part of a £44m upgrade completed in October 2015 The roof comprises about 400 translucent, plastic panels used to bring in light to the station concourse The panels are made of ethylene tetrafluoroethylene (ETFE) - a light but strong plastic that has become popular in construction It is the same material used to make the domes at the Eden Project in Cornwall Each panel was created using computer modelling technology It was designed by architects BDP who also carried out the award-winning Piccadilly Station refurbishment So it's not a Grimshaw design (as at Reading), though these ETFE "polythene bag" roofs are his baby. Perhaps those of us who always through they were a bit of a joke have a point. |
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« Last Edit: October 19, 2016, 13:12:32 by stuving »
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Tim
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« Reply #1 on: October 19, 2016, 13:11:17 » |
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I am no great fan of ETFE for roofs in what are supposed to be permanent buildings. I wonder if NR» used the same contractors as did the leaky ETFE roof at Newport. Perhaps they should only awarded work in the dry side of the country.
A couple of points here though are that if the roof had been made of something more solid you would be looking at more serious injuries when it fails and the station would probably still be closed.
Also it strikes me as odd that ETFE despite having become a very popular material is still only available in relatively narrow widths which have to be welded together in every project it is used in.
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ChrisB
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« Reply #2 on: October 19, 2016, 13:35:16 » |
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I understand that these panels are inflated - & something went wrong with that. The panels themselves I heard are AOK.
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Tim
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« Reply #3 on: October 19, 2016, 15:04:06 » |
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I understand that these panels are inflated - & something went wrong with that. The panels themselves I heard are AOK.
I think "pillow" is probably more descriptive than "panel". AIUI▸ , they are a double layer and inflated after installation. They then need to have their internal pressure regulated to compensate for expansion of the air inside with temperature rises and loss of air through small air leaks. Typically, a roof requires air piping and a small unit pumping dehumidified top-up air into them. In a power cut situation, they will deflate in a few hours. No great problem except deflated pillows provide less insulation and shed rain less efficiently. The report and photo suggests that a large quantity of rain water had accumulated on or perhaps inside the pillow (photo suggests water-bourn muck on the lower sheet of plastic) causing a burst and drenching of those below. Apparently they can be vulnerable to peck damage by bird. I note 2 pigeons in the photo. |
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broadgage
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« Reply #4 on: October 19, 2016, 16:31:33 » |
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What a daft idea !
Am inflatable roof, that needs a continual air supply through miles of small pipes that will assuredly leak, made of a material with a limited life, and that birds can peck holes in.
What is wrong with a steel frame containing either large pieces of wire reinforced glass, or perhaps polycarbonate.
Wired glass lasts almost indefinitely, is fire resisting, and in the unlikely event of breakage, the wire holds the pieces together thereby avoiding injury to those below.
The steel frame should last centuries.
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A proper intercity train has a minimum of 8 coaches, gangwayed throughout, with first at one end, and a full sized buffet car between first and standard.
It has space for cycles, surfboards,luggage etc.
A 5 car DMU▸ is not a proper inter-city train. The 5+5 and 9 car DMUs are almost as bad.
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chrisr_75
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« Reply #5 on: October 19, 2016, 16:42:17 » |
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What a daft idea !
Am inflatable roof, that needs a continual air supply through miles of small pipes that will assuredly leak, made of a material with a limited life, and that birds can peck holes in.
What is wrong with a steel frame containing either large pieces of wire reinforced glass, or perhaps polycarbonate.
Wired glass lasts almost indefinitely, is fire resisting, and in the unlikely event of breakage, the wire holds the pieces together thereby avoiding injury to those below.
The steel frame should last centuries.
My thoughts entirely! I guess glass, steel and polycarb are a bit too old skool now...  |
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ellendune
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« Reply #6 on: October 19, 2016, 17:49:28 » |
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I suspect the weight of the Glass would significantly increase the cost of the supporting structure.
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Tim
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« Reply #7 on: October 20, 2016, 07:43:15 » |
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correct. meaning more money spent on steel and shorter spans/more pillars
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Rhydgaled
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« Reply #8 on: October 20, 2016, 08:22:09 » |
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Oh dear, I think the roof of the open space in the middle of the building I work in is made of this stuff ('Eden Plastic' as I call it, because ethylene tetrafluoroethylene is too hard to remember and everyone seems to use the Eden Project as an example when describing what it is). Mind you there were pepole walking on the roof here a few weeks back, and they didn't fall through it, so maybe it isn't the same stuff.
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Don't DOO▸ it, keep the guard (but it probably wouldn't be a bad idea if the driver unlocked the doors on arrival at calling points).
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caliwag
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« Reply #9 on: October 20, 2016, 11:56:44 » |
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It's the extremes of snow load that flat roof structures are designed for rather than material surely!
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broadgage
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« Reply #10 on: October 20, 2016, 14:21:50 » |
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I suspect the weight of the Glass would significantly increase the cost of the supporting structure.
Yes it probably would. But not insurmountably, large roofs constructed of iron or steel and glazed with either real glass or a substitute like polycarbonate are an established technology that works well and lasts well. Consider older stations like Paddington or Waterloo for example. |
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A proper intercity train has a minimum of 8 coaches, gangwayed throughout, with first at one end, and a full sized buffet car between first and standard.
It has space for cycles, surfboards,luggage etc.
A 5 car DMU▸ is not a proper inter-city train. The 5+5 and 9 car DMUs are almost as bad.
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eightf48544
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« Reply #11 on: October 20, 2016, 16:32:50 » |
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Who investigates incidents like this?
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ChrisB
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« Reply #12 on: October 20, 2016, 16:46:40 » |
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The architect/construction company as it's only been up less than a year, I would have thought - under the warranty process
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Tim
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« Reply #13 on: October 21, 2016, 09:42:08 » |
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It's the extremes of snow load that flat roof structures are designed for rather than material surely!
Possibly correct, but I wonder if standards are allowed to be lower for this kind of roof due to a failure being much less dangerous than a solid roof crashing down, |
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ellendune
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« Reply #14 on: October 21, 2016, 10:46:59 » |
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It's the extremes of snow load that flat roof structures are designed for rather than material surely!
Possibly correct, but I wonder if standards are allowed to be lower for this kind of roof due to a failure being much less dangerous than a solid roof crashing down, I once knew a person who designed a net to cover a waste transfer station that would gently lay itself down if the snow load was too much. This was on the basis that if there was that much snow the bin lorries would not be able to get out anyway. However, this is different - if it were ice it really could do very serious injury. I could not see lower standards ever passing Requirement A1 of the Building Regulations http://www.legislation.gov.uk/uksi/2010/2214/schedule/1/made |
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