SPINNAKER TOWER
The Spinnaker Tower which opened in October 2005, is situated right on the edge of Portsmouth Harbour on the waterfront of the Gunwharf Quays development.
It is higher than the London Eye, Blackpool tower and Big Ben and at 170m is the tallest publicly accessible structure in the UK.
The tower was originally conceived as part of the Millenium projects, intended to celebrate the move into the new Millenium in the year 2000.
Portsmouth applied for a lottery grant for a range of projects as part of the Portsmouth Harbour regeneration scheme with the tower as its focal point.
In 1995 the project was awarded a lottery grant of £38 million towards the project.
Three different designs for the tower were proposed the Spinnaker design, a tripod design intended to emulate ship funnels and a twin tower design holding a large glass globe at the top. The final decision of the choice of design was given to the residents of Portsmouth, exhibitions were held in various locations around the area, with visitors being able to cast their vote, 13,000 people atended and voted at these exhibitions, with more than 60% favouring the Spinnaker design.
Work on the construction of the tower began in November 2001 with a concrete dam built as protection of the site from the sea, then 84, 1m square piles were driven into the seabed that form the foundations for the tower.
The legs of the tower, constructed out of steel reinforced concrete, were formed using a process known as slip forming.
The slip form tooling was built in Austria, it involves the use of hydraulic cylinders which control the wooden shuttering and allow continuous concrete pouring.
The construction of the legs continued until September 2003.
The supporting prefabricated steelwork for the spinnaker was assembled on site, in the very restricted space available at the tower base and was lifted into position during March 2004.
The remainder of the spinnaker steelwork was then assembled and lifted into position by crane, this process continued until the summer of 2004.
Next the tower was painted, by hand, by workers often using abseiling techniques to access the tower exterior.
In January 2005 the top section of the tower was assembled, this part of the tower is constructed as a tubular steel frame, coated in glass reinforced plastic. Shortly after this the tower crane used throughout the build was removed.
During February 2005 the external lift was installed, this caused many difficulties in design and installation for the specialist lift engineers from Italy.
The development of the tower has had many technical difficulties to deal with and has been subject to various criticisms on the political front, in terms of cost and timing, but these have now been overcome, except for the external lift which is still not operational.
The tower opened for business in October 2005, offering panaramic views across Portsmouth Harbour, across the Solent to the Isle of Wight and far beyond.The viewing distances on a clear day are claimed to be 23 miles.
The tower has three viewing decks. Deck1 is at a height of 100m, has full height glass walls and is home to the largest glass floor in Europe.
Deck2 is at 105m and is home to the 'time telescopes'. Deck 3, known as the 'Crows Nest' is at 110m high and is open to the elements.
For more information visit the Spinnaker Tower Website
