| Name | Tower Bridge, London |
|---|---|
| Who | |
| Owner | City Bridge Trust for the Corporation of London |
| Design | John Wolfe Barry, Henry Marc Brunel |
| Architectural Design | Sir Horace James (died 1887) then George Daniel Stevenson |
| Contractor | Sir William Arrol |
| When | 1894 |
| Where | Central London over the River Thames next to the Tower of London |
| Latitude | N 51 30' 20" |
| Longitude | W 00 04' 31" |
| Why | This road bridge over the Thames is a London icon and connects Tower Hamlets with Southwark. |
| What | |
| Overall type | Bascule Bridge - bascule means ‘see-saw’. As each half of the span is rotated upwards,
its weight is balanced by a force on the opposite end (it can be opened and shut in 5 minutes). The central lifting span has two cantilever trusses and the two outer spans are suspension bridges anchored to the towers and to the ground on the river banks. The horizontal forces pulling on the towers are reacted against each other through the pedestrian high level truss walkway. |
| Width | 18.3 m. |
| Length | 286.5 m. |
| Spans | Main span 60.96 m. Side spans 82.3 m. |
| Height of footbridge between towers | 43 m. The bridge was built by cantilevering out from the towers 16.75 m. and placing a suspended span of 36.6 m. between them. |
| Materials | Steel clad in granite and stone masonry |
| Foundations | The piers support the towers but also house the machinery to operate the bascules. To build them large wrought iron boxes (caissons - 12 for each pier) were sunk about 6.5 m into the bed of the river. They were filled with concrete then clad with granite brickwork above river bed level. The towers built on the foundations consist of a steel frame faced with granite and Portland stone. The steel frame has 4 octagonal columns connected by deep beams, secondary beams and diagonal steel bracings (to resist wind laods) at 4 levels including the walkway. |
| How to read a bridge | Read more about suspension bridges..... Read more about trusses..... Read more about the book metaphor..... |
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