Runnymede Bridge, M25 & A30, London Orbital Motorway. I think I can count 14 lanes!
1961: Bridge built for A30
1978: Bronze Age Site found. A Late Bronze Age waterfront site with exceptional preservation of deposits buried under the flood silts of the Thames - The foundations of a Late Bronze Age enclosure stockade set in the edge of the contemporary river channel
The ancient river bank had been revetted with a
double row of vertical pile-driven timbers set a short
distance into the channel. ...
Many of the river channel silts yielded occupation refuse which belongs consistently to the Late Bronze Age and is comparable with that on the river bank. ...
The waterfront structure is envisaged more as a wharf than a purely defensive work ...
A minimal reconstruction might see the piles extending upwards to support a series of horizontal timbers level with the crest of the river bank, and perhaps tied in to post-set timbers there.
For a functioning wharf capable of accommodating river craft, the contemporary river level would have been fairly critical ...
A cusping plan evident for the waterfront would have provided a framework for division in terms of function or moorings allocations, even if this form originated in the attainment of greater structural rigidity.
An inclined layer of brushwood on the riverbed overlain by a few branches was enclosed by one ‘bay’ and is tentatively interpreted as a beaching ramp, or hard, usable in times of low water.
Outlying posts recovered further into the river channel could have been mooring posts or supports for narrow walkways or for fences.
1983: Second bridge added for M25
The design of the new bridge to carry M25 across the River Thames alongside the crossing
designed by Sir Edwin Lutyens at Runnymede presented particular aesthetic and engineering
problems. This crossing was built in 1961 as part of A30 Staines Bypass and the original
bridge is a low and wide arch bridge with brick spandrels.
For M25, it was decided at an early stage, that merely to provide an even wider replica alongside would have been wrong visually as well as being difficult and expensive to construct.
The solution chosen appears as an open spandrel arch of the same basic shape, but the construction is in fact a series of parallel concrete frames, each one made up of two trapezoidal portal rings which ensure that loads are transferred vertically to the ground to avoid disturbing the foundations of the older bridge. The open spandrels allow light to penetrate and thus avoid an undesirable tunnel effect.
The design, by Ove Arup and Partners, has been much praised for producing a pleasing new bridge which preserves and enhances the integrity of the original.
Right bank. Dearsley Island up brook
Site of Wraysbury Ferry
Ferry Lane on Right bank above Colne Brook below Bell Weir Lock
1890: Wraysbury Ferry, Francis Frith -
Wraysbury Ferry, Francis Frith
Left bank above Runnymede Bridge