A team of experts and government officials has begun examining the construction materials used to build the 13-story apartment house that toppled over on Saturday in Shanghai's Minhang District, killing a worker who was inside.

The district government said last night that the emergency rescue phase of the operation had been completed and the focus was now on finding what went wrong at the nearly completed structure. Officials did not say when they expected to finish their probe.

Meanwhile every half hour, inspectors were monitoring the other buildings in the complex, nearby homes, a flood-control wall and area pipes to prevent possible problems.

Investigators took samples of the building's key construction materials such as concrete and steel bars for laboratory analysis.

Architectural experts who examined photographs of the wreckage said they suspected that the collapse occurred because of the excavation of a garage area under the building and the use of substandard materials for the structure's foundation.

Meanwhile, hundreds of people who bought apartments in the 10-building complex where the mishap occurred - Lotus Riverside - were waiting for answers about what will happen to their investments. More than 70 percent of them had submitted a request to get their money back by 5:00 PM on Monday.

Owners posted a statement at the developer's office, appealing for a refund and mortgage loan interest compensation within the next month.

"The price gap of purchasing a similar apartment nearby should also be addressed," said one of the buyers surnamed Sheng.

The government gave no direct response to the request, saying only that "all investors' money is safe."

The community has 629 apartments, with 489 of them sold.

District authorities said earlier they had put nine people from the developer, construction contractor and supervisor "under control," without elaborating. The developer's bank account was also "under control," the district said.

At the collapse site on Monday, six digging machines were working to refill the underground garage area with earth.

Reconstruction was also under way on a flood wall that collapsed the day before the building fell. It was apparently damaged by a huge pile of earth that had been removed from the garage site and placed near it.

The Shanghai construction authority published a notice on its Website, saying that it would launch tougher testing of reinforcing steel bars used in local building construction.

(Shanghai Daily June 30, 2009)