Housing estate refuses to come down without a struggle
Lower Ngau Tau Kok Estate may have been built more than 40 years ago, but its designers used what one engineer describes as 'a very modern approach'.
It is this approach that is posing a challenge to the workers who are now pulling it down.
Five of the seven 16-floor buildings were made with prefabricated components.
And instead of being able to simply crush the concrete, the workers are having to remove these components piece by piece.
Engineers have to check how the components were put together and workers have to cut the cables that attach the pieces to one another.
Holes are then drilled in the components and tower cranes are used to take them away.
Lower Ngau Tau Kok is the first of Hong Kong's old public housing estates to be demolished in this way.
'It was a very modern approach for its time,' Housing Department chief structural engineer Martin Tsoi Wai-tong said of the construction method.
The demolition, started in May and due to finish in September 2012, is costing HK$105 million, 20 to 30 per cent more than other projects of the same scale. Demolition of one floor takes four days, half a day longer than average.
If the usual concrete-crushing approach was used, the structure would become unstable and the building might gradually collapse, Tsoi said. Metal columns are being used to support the structure.
The estate's Block 10 was the first building to be torn down in this way and work on Block 11 has just started.
But the method has its advantages - it is quieter and more of the waste can be reused.
The project will generate 160,000 tonnes of waste and Tsoi said they were trying to reuse most of it. Components like stairs will be crushed to build roads or transferred to other construction sites.
Demolition of the estate is part of the Comprehensive Development Programme, a Housing Authority project aimed at improving tenants' living conditions.
Lower Ngau Tau Kok Estate is the 57th and last estate to be demolished under the project.
The estate housed 3,800 families, and 80 per cent have moved into the upper estate and other areas.
After the demolition, a 33-floor building with 570 flats and a cultural centre will be built, due for completion in April 2015.