استكمالا لمشاركتي السابقة ارفق لكم رأي المهندسيين الصينيين بأسباب
Errors in construction procedure were the main cause of the 13-story building on Lianhua Road, Minhang District toppling, Shanghai government officials said Friday at a press conference.
Workers piled excavated earth up to 10 meters high on the north side of the building at Lotus Riverside complex while digging a 4.6-meter underground garage at the same time.
The pressure on both sides moved the foundations horizontally and they were unable to support the building, Huang Rong, director of the Shanghai Construction and Communication Commission, told a packed press conference.
The building toppled at about 6am on June 27. One worker was killed.
There was no problem with the geological survey, design or construction materials, officials said.
After three days of emergency work, the garage has been filled with earth and the pile of earth outside is now only half a meter high.
The surrounding apartment houses have been declared structurally sound and safe.
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.
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.