Ο ανεξάρτητος δικτυακός τόπος της σχολής Πολιτικών Μηχανικών Εθνικού Μετσόβιου Πολυτεχνείου
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SATURDAY'S deadly collapse of an apartment building in Shanghai's Minhang District was the result of "an elementary mistake," and the builder should have paid attention to "obvious" warning signs that the project was dangerously in trouble, a source close to the investigation into the mishap told Shanghai Daily yesterday.
After examining the wreckage and photos, investigative team members suspect the building toppled on its side because of an excavation project designed to create an underground garage for the nearly completed 13-story structure, the source said.
A large amount of dirt from the garage excavation was piled up alongside the building, and the weight of the dirt combined with heavy rain apparently caused the building's foundation to shift and the structure to tip over.
That preliminary accident scenario was provided by Wu Hang, an assistant to Jiang Huancheng, who is a member of a 12-person investigative team composed of architectural and government officials that was set up by the city government to find out what caused the collapse.
Jiang was the designer of Shanghai's landmark Oriental Pearl TV Tower, and Wu is his assistant at Jiang Architects & Engineers Co.
It could not be learned when the full report would be released.
The building collapsed on Saturday morning at the Lotus Riverside residential complex along the Dianpu River. The structure was part of an 11-building community developed by the Shanghai Meidu Real Estate Co Ltd and built by Shanghai Zhongxin Construction Co.
Apartment owners were scheduled to begin moving in by the end of the year.
"We believe that the cause of the collapse was technically very simple, based on what all the evidence has shown," Wu said.
"It's common sense among construction professionals that the earth from an underground pit should be removed as soon as possible to keep it from causing too much pressure."
An architectural engineering professor from Tongji University who asked to remain anonymous echoed Wu's view. He said the collapse of a flood wall next to the earth pile a day before the building fell proved the pressure from the weight of the debris had changed the underground structure of the area.
Wu said there were obvious warning signs to indicate impending danger, but they were neglected by the builder.
On Friday, local media reported cracks in the flood wall along the Dianpu River. The builder, however, continued digging the underground garage and piling the mud next to the building during the night. The building toppled shortly before 6am the next day following a heavy thunderstorm. A worker who was inside the building at the time died.
The investigation experts found that no reinforcing structures had been installed around the pit, Wu said.
"Shanghai has a soft soil structure," he said. "The builder should have been aware of that basic knowledge and used supports in the digging process. The mistake was unbelievable."
City construction authorities were continuing their round-the-clock monitoring yesterday of all the other buildings inside the Lotus complex as well as several nearby residential buildings. All were reported to be safe so far.
Πηγή ShanghaiDaily.comAccording to officials at Guangqi the builder could have saved up to seven million yuan (US$1.02 million) by keeping the excavated earth inside the construction site. It could then be used on green belts in the residential compound and there would have been no cost for transportation.
The earth excavated from an unfinished garage beneath the collapsed building was piled up to nine meters high.
The dumped earth and the empty space under the structure combined to upset the foundations of the building, and caused the collapse, Wu Hang, an assistant in the investigative team set up by the city government, said in previous reports.