220 stories in 90 days how long will it last. - Page 1
Forum section: electronics / general

author: G7PSK
author_rank: Super Contributor
timestamp: June 26, 2012, 06:08:08 pm
content: The Chinese are planning to build the worlds tallest building at 838 meters high and 220 stories and all in 90 days.http://www.propertyoverseastoday.com/news_features/chinese-firm-aims-to-build-worldE28099s-tallest-building-in-just-90-daysi wonder how long it will last with all the fake materials that are quite likely to get included in it.

author: bullet308
author_rank: Frequent Contributor
timestamp: June 26, 2012, 06:18:01 pm
content: It would seem to be a viable means of building such a structure. They way they have modularized it actually seems rather overbuilt for the smaller structures I have seen using this method.This also offers up the prospect of the Chinese being able to do something else that nobody has done before...export prefab skyscrapers to anywhere in the world.

author: PeteInTexas
author_rank: Frequent Contributor
timestamp: June 26, 2012, 06:45:04 pm
content: Quote from: bullet308 on June 26, 2012, 06:18:01 pmHow will it pass local building codes in countries/states that take these things seriously? Just thinking about earthquake "proofing" in California and Hurrincane hardening in the Gulf Coast.

author: bullet308
author_rank: Frequent Contributor
timestamp: June 26, 2012, 07:13:06 pm
content: You underestimate the quality of Chinese engineering and manufacture. The Chinese collectively can achieve pretty much any level of build quality they care to and that somebody is willing to pay for, from dollar store merchandise to manned spacecraft. If they need to build those modules to meet a specific code, they can buy access to the code just like any other builder and do whatever it requires to meet it.From what I have seen of their methodology, these buildings have a metric assload of steel in them, all arranged in to tidy, relatively compact boxes that then lock together. I suspect that if they put a proper foundation under it, it will work out fine.

author: Bored@Work
author_rank: Super Contributor
timestamp: June 26, 2012, 07:23:08 pm
content: There is an upper limit how long it has to last in China.First, you get 40 or 50 year land leases in China for commercial use (I am too lazy to look up it it was 40 or 50 years). What happens after your lease expires is not really clear today, so an investor will likely not plan to erect a building that lasts 100 years, but more likely one that lasts 35, 40 years and a bit.Second, if you build in a boom region in China you probably want to replace a building after 10 to 15 years with something better, higher, more glamorous.Knowing that limited lifetime of the building you can take shortcuts.

author: SeanB
author_rank: Super Contributor
timestamp: June 26, 2012, 07:40:12 pm
content: A simple demonstration of assembly line processing. Build it all in separate factories and then bring it together in a single stage of final assembly. Kind of like a vehicle production line, where a chassis will spend a week or more going down the line, but a new one pops off every 20 minutes at the end.

author: G7PSK
author_rank: Super Contributor
timestamp: June 26, 2012, 09:18:29 pm
content: Well obviously there is no reason that the Chinese should be any more or less capable in engineering and building than any other nation.

author: Unknown
author_rank: Unknown
timestamp: June 26, 2012, 09:32:38 pm
content: Quote from: G7PSK on June 26, 2012, 09:18:29 pmThat's what these guys figured!http://gizmodo.com/5304233/entire-new-13+story-building-tips-over-in-shanghai/gallery/1

author: EEVblog
author_rank: Unknown
timestamp: June 26, 2012, 10:49:41 pm
content: I am constantly amazed at how they can construct entire buildings in often less time than it takes us EE's to design and build a board.Dave.

author: digsys
author_rank: Unknown
timestamp: June 26, 2012, 11:55:40 pm
content: QuoteSTILL looks perfectly usable to me .. just on another plane :-) Just needs the furnishings redecorated.

author: bullet308
author_rank: Frequent Contributor
timestamp: June 27, 2012, 01:22:35 am
content: Obvious problems with the foundation, but look at how friggin' strong that building was to stay intact like that.

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 27, 2012, 04:33:25 am
content: i thought this is about 1001 nights "stories". looked at the pic. yeah its friggin impossible for a building collapsed still intact like that, its an excellent engineering achievement if its a real life, or just overkill usage of materials. no engineers can outsmart nature. the way its tipped either the land is not stable (too "mild" at one side) or landslide from the side pushing the building or the building is not straight up while built. as the last one seems impossible since no idiot engineer can build a building too leaned or excessively "not up straight". now 220 "storeys" in 3 months? nearly 1km tall? let it occupied for 1 year, its another engineering achievement! deserves a "story" in history book, or that crappy "guiness stout" book of record.

author: G7PSK
author_rank: Super Contributor
timestamp: June 27, 2012, 07:33:16 am
content: Quote from: Mechatrommer on June 27, 2012, 04:33:25 amAnother win for technology (auto spell check). There are famous cases where builders have continued to build despite a bad start, most famous of all is in Italy.

author: johnboxall
author_rank: Unknown
timestamp: June 27, 2012, 11:51:40 am
content: Quote from: ErikTheNorwegian on June 27, 2012, 11:02:18 amReminds me of the old Krushchev blocks. If something goes wrong, the Chinese can always try and bury the evidence...fromhttp://blogs.crikey.com.au/planetalking/2011/07/25/china-caught-burying-crashed-train-cars-and-the-truth/

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: June 27, 2012, 02:18:33 pm
content: QuoteThey were my exact thoughts when I saw it a while ago.I saw some other photos of the same collapse, the piles had no steel reinforcing in them.

author: G7PSK
author_rank: Super Contributor
timestamp: June 27, 2012, 02:46:51 pm
content: I seem to remember that block falling some time ago in a typhoon. The building is obviously far to wide and high for its depth and would not take a lot to push over wind wise. Steel in the foundations would just shear or bend in any case in such a scenario.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: June 28, 2012, 06:37:31 am
content: I'll admit that I know squat about building construction, but I thought the steel in the piles was for it's tensile strength, and that it would help prevent the shearing of the piles.From memory the piles sheared neatly at about ground level, and I could see no reinforcing in them.Isn't it normal to put steel reinforcing into concrete piles?

author: T4P
author_rank: Super Contributor
timestamp: June 28, 2012, 07:31:47 am
content: Quote from: HackedFridgeMagnet on June 28, 2012, 06:37:31 amAt least, outside of china

author: G7PSK
author_rank: Super Contributor
timestamp: June 28, 2012, 09:19:23 am
content: It is possible that if there was a violent ground slip that the inertia of the building will cause the rebar to shear at the point of separation in the concrete pour if there was no bonding at that point due to a damp proof membrane, I have seen similar in a high wall blown over by the wind where a damp proofing membrane had been used which allowed corrosion to occur on the rebar ties such that the rebar looked like it had been cut.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: June 28, 2012, 11:46:11 am
content: QuoteSome discussion.Here are some other pictures of what seems to be the same building.

author: Architect_1077
author_rank: Regular Contributor
timestamp: June 28, 2012, 01:38:10 pm
content: Much like in electronic circuits, it all comes down to what the building has been designed to withstand and/or whether or not those specs were followed through during the construction phase. Many things can go wrong in a building, anything from the engineers miscalculating the forces involved to the contractors skimping on material quality during construction, or even unpredictable circumstances.When it comes to earthquakes, the "forces involved" part is an extremely grey and vast area, simply because earthquakes are very unpredictable forces, being a phenomenon which is not yet fully understood. In the OP example, that building collapse doesn't mean there was necessarily malpractice. It could simply be that the building code model used was not enough to guarantee that the building would withstand the forces involved inthat particular earthquake. The Kobe earthquake of 1995 was a prime example of that. The building code used up until that point was simply not enough. It wasn't malpractice, just that until that point no one really knew that an earthquake of that (relatively low) magnitude could cause the type of damage that it did. It proved that our understanding of all the natural forces is still rather incomplete.Edit: I didn't see the link that shows the article where the pictures came from when I posted my reply. After reading it, to me it is a case of irresponsible/incorrect procedures used on site. This would classify as an "unforeseen circumstance".

author: SeanB
author_rank: Super Contributor
timestamp: June 28, 2012, 03:42:16 pm
content: Looks like they just did not go deep enough, and did not use enough steel in the piles, which in any case were too small anyway. Here you basically go down to the bedrock on such a high building, which means around 30m of pile. Otherwise the building is basically floating on sand, and it will move and buckle with time.

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 28, 2012, 04:51:20 pm
content: piles are not meant to hold building from getting pulled upward, it only meant to reach the bedrock (hard ground) and avoid building from sinking, or leaning uneven to the side due to soft soil. high rise building may call for different foundation setup, but this 12 "stories" is not eligible to be called as one. now reading the link again,http://message.snopes.com/showthread.php?t=53958the later decision was to dig underground parking lot at the side, and the worsening mistake was to pile the digged soil on the other side. must not be within the calculation before it was built. decision like this usually come out from the big boss, they believe they can twist facts from impossible to "possible". engineers scratching their head. later on, peoples making "storeys", gossips and speculations.

author: G7PSK
author_rank: Super Contributor
timestamp: June 28, 2012, 05:48:57 pm
content: Piles work as much by friction as anything else and very often do not go down to bedrock. A lot of concrete piles are reinforced with man made fiber such as polypropylene and not steel.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: June 29, 2012, 12:21:17 am
content: QuoteI have been told that the tensile strength of the reinforcing will help stop concrete snapping as lateral forces are exerted, because the pile will start to bend and the outside of the piles bend is under tensile forces, while the inside of the bend is under compressive forces. Because concrete has poor tensile strength, by itself it will snap like a carrot when bent.I am still of the opinion that steel reinforcing probably should've been used here, and probably was supposed to be used, and may have prevented the building from falling.

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 29, 2012, 03:36:16 am
content: Quote from: HackedFridgeMagnet on June 29, 2012, 12:21:17 ami dont think steel will stand a chance for so long underneath the hazardous area (water salt etc) once corroded it will worsen the concrete pile strength. but i'm not civil expert so not 100% sure. but cheaper will usually win, and backed by the "specialists". we have a situation like this few years back, and the code ammended to prohibit tall construction near the hill or slope. not anything to enforce steel in a pile. i can see steel'less piles are still in use, if i'm not mistaken from the look of em and heard rumours. also with newest technology, i can see alot of "cheap" buildings going up these days, esp for low cost apartment. i call them... cupboard buildings. scary if you ask me, but so far no incident yet, hopefully keep that way.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: June 29, 2012, 03:54:32 am
content: Yes I wouldn't like to live in one for too long either.Apart from the rust, the older ones may be safer.I lived in one once that was 25 stories in Hong Kong, that was built on reclaimed swamp land.I used to worry about it quite regularly.

author: SeanB
author_rank: Super Contributor
timestamp: June 29, 2012, 04:36:05 am
content: Steel reinforcing in concrete is good if they are more than 10cm beneath the surface, where the alkaline enviroment will keep them safe for centuries. Problem comes from salt penetrating the surface and changing this alkaline environment to either a neutral or a slightly acid environment, which then causes rust.In the harbour they wanted to remove old WWII antisub barriers, and they took about 5 months longer than anticipated as the reinforcing, aside from being basically lots of old rail track, was still in near perfect condition. Lots of blasting and underwater cutting was needed to get it small enough to crane onto a barge for removal out to sea for reef building.

author: G7PSK
author_rank: Super Contributor
timestamp: June 29, 2012, 09:03:14 pm
content: In the UK the minimum cover for steel reinforcement is 25mm.

author: SeanB
author_rank: Super Contributor
timestamp: June 30, 2012, 06:05:37 am
content: Bridges and sea salt exposure need more than that for long life.