stuving
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« Reply #2100 on: August 29, 2013, 13:57:04 » |
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Yes - some kind soul evidently wanted to stop our endless speculations. The one thing I did miss was about the dollies. Having worked out that long legs would allow the panels to be manoeuvred above the gateline, I had not spotted they have no bracing - so they can pass through the gateline.
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« Last Edit: August 29, 2013, 17:26:00 by stuving »
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Electric train
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« Reply #2101 on: August 29, 2013, 16:54:25 » |
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Yes - some kind could evidently wanted to stop our endless speculations. The one thing I did miss was about the dollies. Having worked out that long legs would allow the panels to be manouevred above the gateline, I had not spotted they have no bracing - so they can pass through the gateline.
Remarkable. Confirms nearly all of our accumulated guess work - just a shame no-one noticed the pics a week ago! Paul Its all been a bit like the manager of the England football team
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Starship just experienced what we call a rapid unscheduled disassembly, or a RUD, during ascent,”
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Phil
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« Reply #2102 on: August 29, 2013, 18:15:00 » |
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Surely allowing long legged dollies through the gateline is discriminatory though? I thought that sort of thing only went on at night-clubs. Tsk.
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grahame
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« Reply #2103 on: August 29, 2013, 18:27:00 » |
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Surely allowing long legged dollies through the gateline is discriminatory though?
I thought you said long legged doggies for a moment there, Phil
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Coffee Shop Admin, Chair of Melksham Rail User Group, TravelWatch SouthWest Board Member
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stuving
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« Reply #2104 on: August 29, 2013, 18:38:49 » |
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Surely allowing long legged dollies through the gateline is discriminatory though? I thought that sort of thing only went on at night-clubs. Tsk.
Well, it was at night. And in a place the public have to buy a ticket to enter, though it was closed at the time. I guess it's in the nature of mechanical engineering to be just stuffed full of double entendres.
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TonyK
Global Moderator
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The artist formerly known as Four Track, Now!
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« Reply #2105 on: August 29, 2013, 19:20:06 » |
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I guess it's in the nature of mechanical engineering to be just stuffed full of double entendres.
My secretary asked if I could think of an example of a double entendre, so I gave her one.
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Now, please!
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stuving
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« Reply #2106 on: August 30, 2013, 20:07:51 » |
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The delivery last night included quite a lot of hardware in addition to the long beams, so the final canopies (those for the gap in the support beams?) are going to be assembled in place.
You will probably have seen that the bare frames (just two spars and two cross-members) of six sections have been assembled, the last two of which are still sitting outside. The other four are in place on their support beams, so I suspect that the reason for fitting them in that form is weight. Being lighter, they can be lifted by the crane over a bigger radius. So, the question is: where is the crane for this lift? I can't work it out from seeing its jib on camera 02/2. It is sill being kept in the middle of P8/9, but then we know it can drive under the support beams. It appears that the sections have always been bolted to the beams, but the spars are still not fixed to each other at their tips, and there are gaps of several cm. Maybe there is a sneaky method of shimming them to spread any gaps more evenly when they are finally bolted through the holes provided.
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paul7575
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« Reply #2107 on: August 30, 2013, 22:39:15 » |
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Here's an idea then... Perhaps once the polystyrene block 'bridge' is in place the crane can operate from on top of it? That would possibly mean that they'd be lifting the sections 'endways on', rather than 'across' the line of the jib, so the load capacity might be reduced?
As I say, just a thought. Unless anyone is daft enough to go down there in the middle of the night I don't suppose we'll find out...
Paul
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stuving
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« Reply #2108 on: August 30, 2013, 23:23:27 » |
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Well, we know the crane drove across the styro-causeway, but that's not the same. The remarkable strength of this soft material depends on its being evenly loaded, so relying on it to stay level when the weight on it tries to tilt would be risky. It would take a lot of effort to calculate its strength, and the consequences of the crane toppling would be so expensive, I doubt it would be worth even thinking about.
The orientation of the load can't affect the load on the crane - its centre of gravity lies in line with the vertical cable. Its weight dictates the maximum radius. Afterthought - being end-on does place the load's centre further out - which maybe you meant - but that's already true anyway.
Looking at the pictures again, it looks as if the crane is the far side of P9 - which makes no sense to me.
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« Last Edit: August 31, 2013, 00:45:34 by stuving »
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paul7575
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« Reply #2109 on: September 03, 2013, 16:28:25 » |
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I had a look at the canopy sections from platform level today, and I think the answer might be that the crawler crane could still operate through the gaps between the sections as they came together. In other words, I'm thinking that even with only one section missing there would still be a gap big enough for the crane jib to have been used. Then it is noticeable that the pair of long 'side members' of what would have effectively been the final section are not yet connected together by 'cross pieces'. So it is possible that they were either craned in separately, or craned in joined to the sections either side.
I've attached a phone picture to show where I mean...
Paul
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paul7575
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« Reply #2110 on: September 03, 2013, 16:48:21 » |
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Couple of photos here showing work on platform edges.
First one is the London end of P8. Coping slabs along this section are being replaced with modern equivalents after building up the existing platform walling to a revised level. This suggests to me that, if that is the solution all the way round the P8/P9 island, there might not be as much upheaval as sometimes thought. The engineering access statement suggests that the platforms will have reduced operational length at certain stages, presumably when they do the middle sections?
The second picture shows the initial stages of building up the concrete foundation strip for the new wall for platform 10, continuing eastward from the short length of block walling previously built alongside the 'coffee shop'. I'd assume that some shuttering will appear next. Still wondering if they'll remove those redundant sleepers visible on the left, or if they'll just be buried...
Paul
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stuving
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« Reply #2111 on: September 03, 2013, 19:37:55 » |
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I had a look at the canopy sections from platform level today, and I think the answer might be that the crawler crane could still operate through the gaps between the sections as they came together. In other words, I'm thinking that even with only one section missing there would still be a gap big enough for the crane jib to have been used. Then it is noticeable that the pair of long 'side members' of what would have effectively been the final section are not yet connected together by 'cross pieces'. So it is possible that they were either craned in separately, or craned in joined to the sections either side.
I've attached a phone picture to show where I mean...
Paul
Yes, I did wonder about that. The difficulty would be limited luffing angle, but maybe modern cranes - presumably the latest ones are all digital now - can change their jib extension as well as luff and hoist in a coordinated manouevre. It may even be possible to input some motion limits and the desired load path and have the crane tell you if it is possible, and then just do it. Mind you, their chosen method still seems a lot of trouble to go to to do it the easy way.
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ellendune
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« Reply #2112 on: September 03, 2013, 19:42:17 » |
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Mind you, their chosen method still seems a lot of trouble to go to to do it the easy way.
So what would you have said was the easy way?
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Jason
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« Reply #2113 on: September 06, 2013, 13:23:42 » |
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There is activity taking place at various locations at the moment.
Clearance of the old depot on the triangle has started, sections of track south of the main shed have disappeared.
The rest of the temporary P10 has gone, workers were constructing the reinforced steel cages for concreting sections earlier this morning.
I noticed that the last vestiges of the old canopy at the eastern end of P7 have been removed too along with the shanty town style corrugated iron temporary section. Does anyone know what the plans are for what used to be the access to the old bridge. That section of the building has been largely stripped down to a shell and sections of the roof were gone as of yesterday evening.
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stuving
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« Reply #2114 on: September 06, 2013, 14:34:55 » |
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Does anyone know what the plans are for what used to be the access to the old bridge. That section of the building has been largely stripped down to a shell and sections of the roof were gone as of yesterday evening.
I was surprised by how long it has taken to remove this part - last time I looked the escalators were still there. As we've not seen them come out on the cameras, presumably they still are there. The plans show the whole of this structure being cleared, leaving the shops next to the heritage station building and what I guess we call the ground level concourse much as they are. The gateline will be straighter and closer to the platforms, and the current roof over will be extended and extra bits added to fill the gaps between it and the new canopies.
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