Reach to where you cannot see

"Piling and foundation engineering are really too costly to build high-rise buildings in Warsaw", a construction manager told us. However, because of land prices (e.g. USD 2,000/ sqm.) and the low supply of plots in the city centre, investors are prepared to pay. We look at two projects near the ONZ roundabout.

Construction of the Inter-Continental hotel is in progress on the plot of land between  the Warsaw Financial Centre and Warsaw Towers. According to engineer Janusz Zytomirski of Porr, (an Austrian General Contractor), with a steel fin on the roof it will reach 163 m. and become the highest reinforced-concrete skeleton building in Poland.

Protected against the elements
Because of its reinforced-concrete structure, the building is very rigid, and less susceptible to wind. The hotel, whose top storey will stand at 153 m,  will go out of plumb by no more than 14 cm. This would be 32 cm  for a  building of similar height, but built on a steel skeleton.  A reinforced concrete construction is however, heavier than one of steel, and its skeleton needs more space. The foundations of the hotel are approximately  20 m under ground level, and the securing slotted walls go 42 metres deep.

Jump lifts
The fast pace they are working at, (see quote above), ,is achieved thanks to self-erecting boarding/shuttering, the pumping of concrete to each position and the work of qualified reinforced concrete specialists. For the first time in Poland, we are using so-called jump lifts, i.e. hotel lifts, (whose cabins are suitably protected), so that there is internal transport for the numerous subcontractors doing finishing and equipping work."

Lower, but still high
The Westin Hotel, whose construction manager is Stefan Ambroziak of Skanska Polska, has - like the Inter-Continental hotel - a reinforced concrete construction. Although Inter-Continental will be twice as high, Westin can also be described as a high-rise building,  according to the Ministerial decision on Urban Development and Construction in 1994, which stipulated that such buildings are those over 55 m.

Zonal installations
"It is more difficult to build a high-rise building, not only because of the technological factors, but also because of the stricter construction regulations. Foundation engineering is different and piling is applied more often, which also increase costs", says Stefan Ambroziak.
In his opinion, an important difference between lower buildings of ,traditional size" and skyscrapers is the design of installations, which are always  zonal. At Westin, it will be enough to design two zones of water installations with a hydro-pump, pumping water to the higher storeys of the building. The sewage system  has 'choking' devices, i.e. pipes with bends which slow down the flow of water.