Hammersmith Flyover

The Hammersmith Flyover flies over a busy gyratory in Hammersmith. In December 2011, the flyover itself was closed due to being unsafe and in desperate need of repairs.

History

The idea of a grade separated crossing of the surface streets below what is now the Hammersmith flyover was first suggested in the late 1940s, however at this point the idea was to build a tunnel under the streets. It soon became apparent, however, that this would not be possible. The main issue was that the tunnel would have to cross beneath London Underground tracks which are in a cutting in the area, and the water table was only a few metres below the level of this cutting, which rendered a tunnel unfeasible.

It was then decided that a flyover should be built, and in 1956 the Ministry of Transport announced it would provide a grant to cover the cost of building the flyover.

The flyover was designed as the first in the UK supported only by central columns. The rationale behind this was that in order to build supporting columns in the conventional fashion, far more land would have had to have been acquired which would have made the project far more expensive.

The flyover was built by Marples, Ridgeway & Partners between 29th February 1960 and 16th November 1961 when it was opened to traffic by Harold Shearman, Chairman of London County Council. Ernest Marples, Transport Minister, was in attendance and declared that it "marks a new age in road planning" and that "it is quite the nicest flyover I have seen in the world". Cost was £1.3 million.

The 2,800 yard dual 24 foot carriageway connected the adjacent sections of the Cromwell Road Extension and the 1,000 yard flyover was supported by 15 tapering columns. It involved a new type of prestressed concrete construction with the precast sections "stitched together" with 33 miles of high tensile steel strands. It had 66 miles of electric cable for de-icing buried below the road surface.

Maps

The area in 1960	The flyover shown in June 1962.

Closure and Repairs

The flyover was inspected during December 2011. This inspection found that cables within the structure were severely corroded. The flyover was closed for safety reasons and work soon began to strengthen the most damaged parts of the flyover in order for it to reopen in time for the 2012 Olympic Games.

Work is currently (As of September 2014) to strengthen the remainder of the structure.

Future

The work to strengthen the flyover will mean it can remain in use for many years. In the longer term, plans exist to transfer the flyover to a tunnel. These plans were supported by Mayor of London, Boris Johnson, in March 2014.

Routes

Route	To	Notes
A4	The WEST, Heathrow Airport
A4	Central London, Olympia
A219	Shepherd's Bush
A219	Fulham
A306	Hammersmith, Barnes
A315	Chiswick
A315	Kensington