D. Medway Bridge Channel Tunnel Rail Link, England (1996-2003)
Medway Bridge is the centre-piece of the over 170
bridge structures on the High Speed Channel Tunnel
Rail Link between London and the English Channel
which is now known as High Speed 1. I was the
Engineering Manager for all the bridges. Medway
Bridge crosses the River Medway near Rochester and
is very visible from it. The bridge runs parallel to the
1960s built M2 motorway balanced cantilever bridge
and the new motorway widening bridge which is
located between the 1960s bridge and the railway
bridge, Figure 20.
balanced cantilever bridge has a main span of
approximately 152m with curved haunches and a
straight in between, with constant depth approach
spans in the region of 40m, Figure 21.
The motorway authorities design for the new road
bridge was envisaged to be a balanced cantilever
main span similar to the 1960s bridge main span and
constant depth approach spans in the region of 80m.
The balanced cantilever span of the new road bridge
was going to have straight haunches and constant
depth in between.
From engineering considerations the main span of the
new railway bridge also needed to be a balanced
cantilever.
From an aesthetic and good neighbourliness
consideration we felt that the main piers of the new
road and rail bridges should align with the main piers
of the 1960s bridge, and the soffit of the main span of
the new road and rail bridges should be curved to be
visually sympathetic with the curved soffit of the
1960s bridge.
It took some persuasion to get the motorway
authority to change the straight haunch to a curved
haunch, Figure 22.
Figure 20: Location of the Bridge
For the design of the railway bridge we co-opted Jim
Eyre of Wilkinson Eyre Architects to be our
architectural adviser. From the outset it was obvious
that the railway bridge needed to be visually
compatible with the old and new road bridges,
especially as all three bridges would be seen in distant
views from Rochester and from close up. The 1960s
← Figure 21: View of the 1960s Motorway Bridge
↑ Figure22: Curved haunches of the three
bridges - model
1/2018