A spectacular tower which offers views over a UK harbour town has officially opened to the public.
The Spinnaker Tower is a UK Millennium Commission sponsored project aimed at transforming the waterfront of Portsmouth and Gosport. It forms the focal point of a £200 million regeneration of the Portsmouth Harbour area and will add a new landmark to the South coast of Britain.
Designed by Scott Wilson Advanced Technology group, the tower is a concrete, steel and composite structure that rises 170m from the sea adjacent to Gunwharf Quays. It has three tourist viewing platforms at heights of 100, 105 and 110m that offer views over Portsmouth harbour.
It is constructed upon a 3m thick pile cap and founded on 84 piles, and comprises two inclined slip-formed hexagonal concrete shafts, of 6m across, which merge into a single shaft at 70m. One shaft contains an internal express lift and the other shaft carries a panoramic external lift up the seaward face.
Two elegant crossed bows, fabricated from 10.8m long and 1.5m wide structural steel box sections, rise from the ground, cross between the shafts at 35m and rise to connect with the shaft at 120m. The bow dimensions vary from 10-12m in depth at the base and top of the tower, reducing to 2.5m wide in the central region. Aerofoil shaped ribs span between the bows to give the distinctive ‘Spinnaker’ sail appearance.
A composite spire forms the needle-like top to the concrete A-frame.
The three high-level trapezoidal viewing platforms vary in size from 18m x 14m down to 12m x 4.7m for the highest open deck. A grid of I-section steel beams span between the concrete tower, steel bows and frontal rib beams at each level to support the 150mm thick concrete floor slabs.
Stretching 165 meters (542 feet) above Portsmouth on the south coast, the £35.6 million Spinnaker Tower is expected to attract around 700,000 people a year. Visitors can travel to the three viewing decks using a high speed internal lift or an external elevator. Once at the summit, a glazed floor provides a downward view of the promenade and the intertwining design of the structure itself.
More detail on the software used to check the design of the tower can be found at:
http://www.lusas.com/case/civil/spinnaker_tower.html
A live view of the Spinnaker on webcam can be found at:
