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Thread ID: 141816	2016-03-04 21:14:00	Darwin Rules !	Terry Porritt (14)	PC World Chat

Post ID	Timestamp	Content	User
1416907	2016-03-06 21:45:00	On the One news site, they have john Key talking bla bla bla-- BUT the interesting point, in the video, managed to capture the rear side of the balcony, Have a look at how many supports there were and their sizing, there's at least 8 -- Simply to many people on it clowning about, and everything looks like it was in good shape. 70127013	wainuitech (129)
1416908	2016-03-07 06:54:00	no , lets make relevant comparisons, instead of your stupid one. Its would be ridiculous to have a 20 seater bus & cram 100+ people into it, then have them all jump up & down as the bus goes around a corner. My small ford laser has a towbar on it. That doesnt mean I should attempt to tow a 20ft boat, and then complain when the brakes burn out down a long hill. we have max weight rules for vehicle loads and towing loads. these are listed or written on your vehicle. theres no weight limit you can find for your deck/balcony. you can't look up a manufactures listing. recent video shows only 16 people and none bouncing up and down. thats hardly even crowded. the balcony had plenty of room yet completely utterly failed without it even being full. so its very much like having a bus 3/4 full and it breaks in half.	tweak'e (69)
1416909	2016-03-07 07:00:00	On the One news site, they have john Key talking bla bla bla-- BUT the interesting point, in the video, managed to capture the rear side of the balcony, Have a look at how many supports there were and their sizing, there's at least 8 -- Simply to many people on it clowning about, and everything looks like it was in good shape. 70127013 i counted 11 joists all up. what intrigues me is that they pretty much sheered off at the pivot point on the wall. the basic design is that they are free floating and only secure right at the end of the beam, which will be 2-3m back under the floor. i would have thought they would break more like a greenstick break about half way down the joist, which would be well under the floor instead of at the wall.	tweak'e (69)
1416910	2016-03-07 07:23:00	If you go through the news reports you will find that the video only goes back 15 minutes before the balcony collapsed. There were students on it for 3 hours before that. The singer with the band earlier on saw the balcony bouncing up and down and warned the students on it who mostly left. Subsequently the balcony filled up again and the bouncing resumed. Who knows what damage was caused in that time, before the collapse. This BRANZ report is worth reading www.branz.co.nz 74fce931fbe6ce4 especially where it says that deflections can be up to 20 times static at resonance. There are various reports covering floor design and the effect of rhythmic activity on them www.steelconstruction.info www.civil.umd.edu I doubt whether apartment balconies have been designed with rhythmic dancing or jumping in mind. Key is 'blathering on' about accountability rather than finding out the engineering cause, which in itself would point the way towards accountability. He has the cart before the horse because he doesn't understand the issue. I hope he has some good engineering advisors to show him the error of his thinking.	Terry Porritt (14)
1416911	2016-03-07 09:16:00	TV3 showed a snippet of the new video. It says it starts 15 minutes before the show began, and that the balcony collapsed almost immediately after the band started playing. They said the students were not jumping up and down............well of course not because the band wasn't playing during that 15 minutes, and neither can you see anyone else dancing before the band starts. If the balcony was already weakened because of what had gone on before then just a bit of rhythmic body movement in unison could well have been the cause. It is too much of a coincidence that it collapsed just as the band started. www.newshub.co.nz	Terry Porritt (14)
1416912	2016-03-07 17:36:00	TV3 showed a snippet of the new video. It says it starts 15 minutes before the show began, and that the balcony collapsed almost immediately after the band started playing. They said the students were not jumping up and down............well of course not because the band wasn't playing during that 15 minutes, and neither can you see anyone else dancing before the band starts. If the balcony was already weakened because of what had gone on before then just a bit of rhythmic body movement in unison could well have been the cause. It is too much of a coincidence that it collapsed just as the band started. www.newshub.co.nz Well there you have it it collapsed due to the poor quality of the music the band play	gary67 (56)
1416913	2016-04-06 08:23:00	www.dunedin.govt.nz thats the report into the collapse. however i can save you some reading by quoting part of it....... "The inspections were carried out by visual means only and no opening up or testing of any kind was carried out". so no ruling out material problems, design/build problem (as 3/4 of it is in the building and would have to open up the ceiling to inspect). of interest is that it was built to the old standard and doesn't meet current standard (fail on point loading and joists where notched). also probably not current design, but wont know that cause they never looked!. even more interesting is that commercial building standard is double the weight because "loadings associated with areas where people may congregate".........."people congregating on deck". ie they build commercial decks to support people using the deck but not house decks. i find that weird.	tweak'e (69)
1416914	2016-04-06 10:06:00	The report seems to be reasonably thorough. It would have been very interesting if they had carried out load/deflection tests on the other balconies, and vibration tests to determine natural frequencies with different static masses added. Their conclusion 10.1.4 is telling in regard to exceeding the static 2kN/m² design load, and if people are going to"congregate" then the design load should be doubled to 4kN/m². With regard to the students moving: 10.1.5 Whilst the occupants were not jumping, there was a measure of movement to the beat of the music. It is graphically telling that on the third, (approximately), movement the balcony collapsed from the right hand end. The movement would add a measure of dynamic loading that amplified the static gravity loading. The report does not discuss the observed "bouncing" of the balcony during the previous 3 hours when warm up bands were playing, or whether there was any damage or weakening caused by this.	Terry Porritt (14)
1416915	2016-04-06 10:51:00	certainly would be interesting to see vibrating load testing done. especially with different designs and construction. the free float design currently used would flex more. would that be better or worse than a more rigid fixed construction. does the notching change the vibration, as its a bigger bit of timber with the end cut down for the balcony compared to modern construction of just single sized timber. its not a party without dancing out on the deck.	tweak'e (69)
1416916	2016-04-06 11:15:00	This "notching" of the joists would appear to be a bad feature though it has been widely done as far as I can see wherever balconies are built. It's to lower the deck below room floor level so that water does not get under the windows/doors. The notching is more or less at the point of maximum stress in the joists, and will be a stress raiser. The report recommends further research into this. The deck would be designed with the reduced joist depth taken into account. So, partying and dancing should indeed be taken into account when they design a balcony, the same way that they do when designing a dance floor. Quote: Design for rhythmic activity Where floors are likely to be subject to dancing and jumping activities characterised by synchronised crowd movement, the floor must be designed for ultimate limit state considerations in accordance with the requirements given in the National Annex to BS EN 1991-1-1[4]. According to these Standards: The floor may be designed to have a fundamental frequency of at least 8.4 Hz vertically and at least 4 Hz horizontally, in which case the resonant effects need not be evaluated. or The floor should be designed to resist the anticipated dynamic loads due to rhythmic activity which should be considered as an additional imposed load case. The vertical natural frequency of the floor should be evaluated for the appropriate mode of vibration for an empty structure. www.steelconstruction.info	Terry Porritt (14)
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