Nearly completed high-rise collapses in Shanghai
Nearly completed high-rise collapses in Shanghai
(OP)
HONG KONG (Reuters) – A 13-storey residential building under construction in Shanghai collapsed Saturday, killing one worker and highlighting the dangers of shoddy building in fast-urbanising China.
The building, in the outskirts of the city, collapsed at around 6 a.m. (6 p.m. ET) with one construction worker killed, the official Xinhua news agency reported.
The block of high-rise residential flats was shown toppled onto its side in a muddy construction site, in footage from Hong Kong's Cable Television. Exposed pilings stood in the remains of the building's foundations.
It appeared to be almost complete with fitted windows and a finished, tiled facade. Other similar-looking blocks in the same property development were still standing nearby.
Shoddy construction and the use of sub-standard materials is a concern in China's construction sector as the country scrambles to build out cities and finish massive infrastructure projects to keep pace with fast economic growth.
Construction-related accidents last year included the collapse of a steel arch on a new railway bridge, which killed at least seven and a crane which fell on a kindergarten killing five.
The collapse of dozens of schools during last year's Sichuan earthquake, sometimes when buildings around them withstood the tremor, also led to a wave of public outrage about corrupt officials and construction firms.
Source: http://ne ws.yahoo.c om/s/nm/20 090627/wl_ nm/us_chin a_building
Pictures:
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The building, in the outskirts of the city, collapsed at around 6 a.m. (6 p.m. ET) with one construction worker killed, the official Xinhua news agency reported.
The block of high-rise residential flats was shown toppled onto its side in a muddy construction site, in footage from Hong Kong's Cable Television. Exposed pilings stood in the remains of the building's foundations.
It appeared to be almost complete with fitted windows and a finished, tiled facade. Other similar-looking blocks in the same property development were still standing nearby.
Shoddy construction and the use of sub-standard materials is a concern in China's construction sector as the country scrambles to build out cities and finish massive infrastructure projects to keep pace with fast economic growth.
Construction-related accidents last year included the collapse of a steel arch on a new railway bridge, which killed at least seven and a crane which fell on a kindergarten killing five.
The collapse of dozens of schools during last year's Sichuan earthquake, sometimes when buildings around them withstood the tremor, also led to a wave of public outrage about corrupt officials and construction firms.
Source: http://ne
Pictures:
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Clansman
If a builder has built a house for a man and has not made his work sound, and the house which he has built has fallen down and so caused the death of the householder, that builder shall be put to death." Code of Hammurabi, c.2040 B.C.






RE: Nearly completed high-rise collapses in Shanghai
RE: Nearly completed high-rise collapses in Shanghai
Have any engineering details been published?
RE: Nearly completed high-rise collapses in Shanghai
RE: Nearly completed high-rise collapses in Shanghai
Besides I think the construction isnot shoddy.
RE: Nearly completed high-rise collapses in Shanghai
The rest of the building looks fine, how many buildings are capable of falling over and remaining in one piece?
PSlem,
It is unlikely that the building was pushed to failure by the soil as the soil is only very low and the weight of the building will be many times this. I would expect that the soil you see is from a circular rotation failure of the soil resulting from the building toppling over.
As always, these things are never clear cut. It would be interesting to see the results of the investigation.
RE: Nearly completed high-rise collapses in Shanghai
Anything we have is purely speculation, but would look at bearing failure on leading edge.
Piles look short...obviously didn't have enough tension capacity for overturning moment.
RE: Nearly completed high-rise collapses in Shanghai
RE: Nearly completed high-rise collapses in Shanghai
BA
RE: Nearly completed high-rise collapses in Shanghai
RE: Nearly completed high-rise collapses in Shanghai
No "slab" or floor structure in the lowest building basement: The building entry floor appears to be resting directly on the mud itself.
RE: Nearly completed high-rise collapses in Shanghai
RE: Nearly completed high-rise collapses in Shanghai
This is the Chinese version of "rollovers".
It looks like there was no basement - the grade beams appear to have been at grade. Consequently, the building CG was much higher, amplifying any settlements and associated OTM due to gravity loads that never should have occurred.
Mike McCann
MMC Engineering
RE: Nearly completed high-rise collapses in Shanghai
RE: Nearly completed high-rise collapses in Shanghai
RE: Nearly completed high-rise collapses in Shanghai
The pile adopt the high-strength prestressed pipe pile.
attached for you information
RE: Nearly completed high-rise collapses in Shanghai
The pile adopt the high-strength prestressed pipe pile.
attached for you information
RE: Nearly completed high-rise collapses in Shanghai
RE: Nearly completed high-rise collapses in Shanghai
RE: Nearly completed high-rise collapses in Shanghai
They were lucky it fell into an empty lot with no people, and not backwards into the roadway.
RE: Nearly completed high-rise collapses in Shanghai
RE: Nearly completed high-rise collapses in Shanghai
But they have others to work with !
RE: Nearly completed high-rise collapses in Shanghai
RE: Nearly completed high-rise collapses in Shanghai
RE: Nearly completed high-rise collapses in Shanghai
the prestressed reinforcements is too smaller to see.
i draw a figure for you all information
RE: Nearly completed high-rise collapses in Shanghai
But the photo's are clear enough, are in close enough detail, and absolutely confirm that no steel was ever inserted in the concrete pile before the concrete was poured. Any steel - no matter how "small" would be pulled and twisted at the break, would be pulled out and be linkning the twp pile sections. I can state absolutely that in that particular photograph of that particular pile at that particular break point, there is no reinforcing steel.
RE: Nearly completed high-rise collapses in Shanghai
At least there is no reinforcement in that broken pile in that photo.
RE: Nearly completed high-rise collapses in Shanghai
RE: Nearly completed high-rise collapses in Shanghai
Mike McCann
MMC Engineering
RE: Nearly completed high-rise collapses in Shanghai
Thanks for the explanation. Is that your sketch or did it come from an investigation?
RE: Nearly completed high-rise collapses in Shanghai
The piles are reinforced as shown on Itdog's drawing.
I don't think that the collapsed riverwall as shown in the first photo coincides with the collapse.
It does, however, show the extent of the development (and the extent of the demolition that may be required).
RE: Nearly completed high-rise collapses in Shanghai
The sketch comes from I discuss with chinese structural egineers in the internet http://
Jack1977 and racookpe1978,
From the below photo, we can see the thin prestressed reforcement.
The dia 500 pipe pile compression capacity is 2000kn
but the shear capacity only 30kn.
RE: Nearly completed high-rise collapses in Shanghai
I believe that the is reinforcement but I believe it is far less that what we would use in the western world.
With a small amount of reinforcement, the concrete tensile stress is dominant. So when the concrete cracks the small reinforcement is subject to high local strains at the crack resulting in it snapping off with very little of it exposed.
In the western world, with minimum reinforcement rules, this type of failure does not usually occur and it is usually a bond failure as well as a tensile failure.
We must be careful about being too opinionated on this one.
RE: Nearly completed high-rise collapses in Shanghai
The wrapped "spool" radial wire shown in the drawing is not clear (also only coat-hanger-wire thin) - if it is present at all. (I would think they would have specified two radial wires, one clockwise, one counterclockwise.) Wire dia? Again, about 1/2 diameter, maybe 7/16.
Further, that spool wire should be spanning the gap between the two broken pile pieces, clearly pulled and distorted out the two ends of the concrete. None (no remnants) is visible in any of the other piles that have separated.
Doubt whether it is there? Get close and look. But that is what the defense/offense lawyers and a good investigating team should be doing now.
Not a observer (me!) off site speculating and scaling from web pictures.
RE: Nearly completed high-rise collapses in Shanghai
It consists of driving a steel casing within a casing. Both are driven simultaneously. Theres a donut shape shoe that's used on the casing. The soil between the casings is forced out during driving; then the space is filled with concrete; then the casings are vibrated out. Light reinforcement is sometimes used. It's supposed to be a quick, economical method of pile installation.
RE: Nearly completed high-rise collapses in Shanghai
Really??
http://dcnonl.com/article/id34398
RE: Nearly completed high-rise collapses in Shanghai
RE: Nearly completed high-rise collapses in Shanghai
The intact structure reminds me of the Kawagishi-Cho apartment building that fell over in the 1964(?) Niigata EQ when the foundation liquefied and lost most of its strength. Structural designer did fine; foundation designer didn't (although in the latter's defense, liquefaction wasn't really part of standard practice then).
RE: Nearly completed high-rise collapses in Shanghai
RE: Nearly completed high-rise collapses in Shanghai
Seems quite possible that the excavation and softening of ground on that side removed lateral support allowing the piles to buckle simply due to compression force. In the picture with the firefighters, the piles appear to have fairly small diameter, therefore small EI. It is far from certain that the dirt pile was the triggering cause.
Photo here is the aforementioned apartment building in Niigata, Japan.
RE: Nearly completed high-rise collapses in Shanghai
Then, look at the breaks of those piles. They all are typical of a diagonal shear failure, upper part moving toward the excavation near the building. No evidence of compression failures. Better reinforcing might have helped, but unlikely would have saved things.
Is vertical reinforcing designed for shear resistance? I doubt it.
Sequence of failure would indicate the piles near the excavation failed first.
This would show the "down-hill" part of the slip moved first towards the open hole there.
RE: Nearly completed high-rise collapses in Shanghai
Hey, at least tower held together even after the impact! Wow!
RE: Nearly completed high-rise collapses in Shanghai
Also, are we able to see the southernmost row of piles exposed? They would be the ones I would check for buckling. I'm under the impression that they are buried and out of sight, and that what we can see are the ones that failed primarily in tension or pulled out.
RE: Nearly completed high-rise collapses in Shanghai
Instead it's likely the excavation was inadequately shored and the front row of piles buckled or were hit, especially considering how under-reinforced they are for a building of this A.R. in a potentially seismic area and that clay soil.
The building should've been able to remain standing even if 20 feet of soil sloughed from under it into the excavation, but the report, done by the architect (conflict of interest)
is so flawed it would make Terzaghi roll over in his grave.
RE: Nearly completed high-rise collapses in Shanghai
We'll probably never know the exact mechanism of initial failure of the piles, for reasons both technical and human.
RE: Nearly completed high-rise collapses in Shanghai
Right about the shear plane not necessarily a circle. Could have been a horizontal weak plane in a weak sediment.
Question comes up about which part of a slippage plane moves first.
I see many slips where an excavation started it and the stuff up-hill them progressively slips.
Here the excavation probably triggered it causing buckling or loss of lateral pile support on the excavation side.
RE: Nearly completed high-rise collapses in Shanghai
NO
012] Building Collapsed In Shanghai (06/27/2009) (Daqi)
At around 5:30am on June 27, an unoccupied building still under construction at Lianhuanan Road in the Minhang district of Shanghai city toppled over. One worker was killed. According to information, a 70 meter section of the flood prevention wall in nearby Dianpu River and that may have something to do with this building collapse.
But the high-resolution photos are really amazing.
(China Daily)
Improper construction methods are believed to be the reason of last Saturday's building collapse in Shanghai, according to a report from the investigation team. The investigation team's report said that workers dug an underground garage on one side of the building while on the other side earth was heaped up to 10 meters high, which was apparently an error in construction, according to a report on eastday.com, Shanghai's official news website. "Any construction company with common sense would not make such a mistake," said an expert from the investigation team.
Earlier this week, there were also reports saying that cracks on the flood-prevention wall near the building, as well as the special geological condition in the water bank area, may be part of the reason for the collapse. "These factors are not the basic reason of this accident," said the expert.
Nine people linked to the building collapse, including the real estate developer, contractor and the supervisor for the project, have been put "under appropriate control", said the official Xinhua News Agency Sunday evening.
(SCMP) Firm's ignorance led to toppling of Shanghai building, report says By Will Clem and Lillian Zhang. July 4, 2009.
An official investigation into the collapse of an unfinished building in Shanghai has said that the accident was due to the construction company's "ignorance", rather than flaws in the design or building materials. However, the report stopped short of apportioning blame, and has been criticised for failing to address key issues.
The report said the collapse was caused by earth, excavated to make a 4.6-metre deep pit for an underground car park alongside the building, being piled to depths of up to 10 metres on the other side of the structure. The weight of the pile created a "pressure differential" which led to a shift in the soil structure, eventually weakening the foundations and causing them to fail. This situation "may" have been aggravated by several days of heavy rain leading up to the collapse, but investigators would not say whether this was a crucial factor. The report said the construction company - Shanghai Zhongxin Construction - "did not consider clearly" that the earth pile could have such a devastating effect.
Investigators stopped short of saying whether the company's errors were negligent or easily avoidable. However, they stressed that the building's foundations and construction materials all complied with the city's building regulations.
Huang Rong , director of the Shanghai Urban Construction and Communications Council, said inspections had shown that none of the remaining 10 apartment blocks was in immediate danger. "The surrounding buildings are now stable," he said. "The safety inspection of these homes will be the second phase of our professional team's work."
Jiang Huancheng , an architect and a lead investigator for the report, said it had been an "enormous shock" to see the site for the first time. "In my 46 years in the industry, I have never seen or heard of this," he said. "To put it simply this was ignorance leading to rashness. We need to take this accident as an important lesson ... and ensure that it does not happen again."
Several days before the release of the report, Wu Hang , Mr Jiang's assistant, accused the construction company of incompetence and lacking "common sense". Mr Wu said the investigation had found there had been no structures to support the walls of the car park pit, and this had been a key factor contributing to the accident.
(1) An underground garage was being dug on the south side, to a depth of 4.6 meters
(2) The excavated dirt was being piled up on the north side, to a height of 10 meters
(3) The building experienced uneven lateral pressure from south and north
(4) This resulted in a lateral pressure of 3,000 tonnes, which was greater than why the pilings could tolerate. Thus the building toppled over in the southerly direction.
(Sina.com)
First, the apartment building was constructed. Then the plan called for an underground garage to be dug out. The excavated soil was piled up on the other side of the building. Heavy rains resulted in water seeping into the ground. The building began to shift and the concrete pilings were snapped due to the uneven lateral pressures.
The building began to tilt.
And thus came the eighth wonder of the world.
RE: Nearly completed high-rise collapses in Shanghai
BA