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BRIEFING DOCUMENT ACTIVE BRIEF: THE SECOND DARTFORD BRIDGE CROSSING

BRIEFING DOCUMENT
ACTIVE BRIEF:
THE SECOND DARTFORD BRIDGE CROSSING
thebrief.net
Closing date:
19/03/07
19th March 2007
your chance to go beyond the conventional.
BRIEF:
THE SECOND DARTFORD BRIDGE CROSSING
LOCATION:
Across the River Thames between West Thurrock and Dartford to the east of London
The M25 London orbital motorway is to be widened to four lanes in each
direction under a 30 year private finance deal from 2008 which it is hoped will
dramatically reduce delays on the infamous stretch of road. One of the worst
bottlenecks and causes of delay to vehicles is the River Thames Crossing to
the east of the capital. Despite the construction of a new four carriageway
bridge in 1991, which doubled the previous capacity provided by twin tunnels,
the crossing has struggled to meet peak capacity. The proposed M25
widening will add two extra lanes of traffic approaching the crossing and so
necessitate construction of an additional four lane bridge.
Description:
A contemporary structure - a technological tour de force - which speaks for its
generation and complements the existing high level cable stayed River Thames
crossing between West Thurrock and Dartford to the east of London. It should
provide four motorway standard traffic lanes while maintaining a 55m navigation
clearance envelope to the river.
Location:
London, England.
Area available for build:
The new structure must cross the River Thames within 500m of the existing bridge and
must be sited so as to enable connection to the existing motorway infrastructure.
Design constraints:
A minimum clearance envelope below the bridge deck of 55m is required over a
100m wide central navigation channel. The height of the towers shall not exceed
148m above ordnance datum (Newlyn) (ODN).
Ground conditions:
The river bed is made up from alluvial river deposits overlying clay, peat and gravel
strata on chalk bedrock. River is approx 20m deep with a tidal range of 6.4m
between -2.8m ODN and +3.6m (ODN).
Climate:
‘British Weather’ with prevailing winds from the west.
Bridge feel:
No preconceived ideas. Must complement the existing structure
Planning for the future:
It is not envisaged that the structure will be modified in the future - but who knows!
Type of engineer:
It’s a unique opportunity, the only criteria is a creative mind.
Judging criteria:
Your submission will be judged against:
Engineering vision
Demonstration of innovation
Pragmatism – a ‘within the realms of possibility’ solution
Design innovation
The quality of the sketch
BRIEF:
THE SECOND DARTFORD BRIDGE CROSSING
LOCATION:
Across the River Thames between West Thurrock and Dartford to the east of London
Key areas for focus:
By 2016 the M25 motorway will be widened to four lanes across its entire length. This will include the approaches to the
River Thames crossing at Dartford to the east of the capital, infamous for its peak hour traffic jams. The Highways
Agency has concluded that a new high level bridge crossing is needed to provide an additional four traffic lanes of
capacity at this pinch-point and provide a structural statement to complement the existing bridge.
Location History
120000BC
The Thames was a tributary of the river Rhine
6500BC
The British Isles separated from the rest of central Europe
50BC
The Romans began building forts along the Thames
18th Century
Thames water quality substantially diminished
1857
The Thames Conservancy Act
1879
Long stretches of the river were raised and protected with
river walls and embankments
19th Century
The Port of London became the largest port in the world
1929
Kent and Essex Councils promoted a Bill for a Dartford to West Thurrock
tunnel crossing
1938
Pilot tunnel completed
1963
First Dartford tunnel constructed at a cost of £13M
1980
Second Dartford tunnel constructed at a cost of £45M
1988
Construction of a high level cable stayed bridge started by the Cementation
Cleveland Dartford Consortium
1991
Queen Elizabeth II Bridge opens at a cost of £114M
2005
Highways Agency confirms M25 widening scheme
2006
Review of Dartford crossing capacity launched by the Highways Agency
The existing structure and natural habitat:
The M25 motorway is one of the busiest stretches of road in Europe with average peak flows reaching 180,000 vehicles
a day approaching the existing crossing.
The River Thames has a tidal range of 6.4m between -2.8m ODN and +3.6m (ODN).
The existing bridge has an 812m cable stayed section with a 450m central span and two 1km viaduct approaches. It has
four 84m pylons mounted on 53m high concrete piers. Two mass concrete gravity caissons with a river bed floor area of
850m2 support the pylons.
The existing bridge has a 2m thick steel deck on an asymmetric vertical curve.
The Thames is one of the cleanest city estuaries in Europe, is of international importance for wading birds and wildfowl
contains 119 fish species.
Sea level is expected to rise between 25 - 50cm by 2050
BRIEF:
THE SECOND DARTFORD BRIDGE CROSSING
LOCATION:
Across the River Thames between West Thurrock and Dartford to the east of London
1. General location map
2. Location
3. Precise location - Google Earth
4. Existing Bridge
BRIEF:
THE SECOND DARTFORD BRIDGE CROSSING
LOCATION:
Across the River Thames between West Thurrock and Dartford to the east of London
Timetable:
Your entry for the Second Dartford Bridge Crossing must arrive by 01/02/2007
Rules - The Brief competition
1
To enter the competition, you must have successfully completed the competition registration form. This only needs
to be completed once, even if submitting an entry for more than one brief.
2
There is no restriction to the number of entries a competitor can submit for each brief, however each entry must
have a unique email address.
3
Registrations will only be confirmed with the inclusion of a valid, operating email address for the applicant.
4
The competition is free to enter and open to anyone aged 18 years and over as of 26 May 2006.
5
Relevant entries must be submitted (and have been received) within the time schedule for each brief.
6
All entries must be original work created by the registered competitor.
7
To be judged, all submitted entries must be accompanied by registered competitors name and contact details.
8
All competition entries, be they hand drawn sketches or digital images, will only be accepted if submitted in the
specified formats (see ‘Enter Your Sketch’ below).
9
All winners will be notified by email.
10
The judges’ decision, in regard to all elements of the competition, is final.
Enter your Sketch - The Brief Competition
All entries should be submitted via the website:
• Submit a Jpeg (.jpg) File
log on to the website and choose ‘upload’ from the main menu, follow the on-screen instructions.
You can submit your entry as a free-hand drawing or as a digital image, judging criteria does not favour one approach
over the other. You can use any media you like to create your sketch we just ask to ensure you end up with a Jpeg
image of around A4 (W297 x H210mm landscape, approx 4MB) in size and any hand drawn entries should be scanned
to this size - you can enter hand-drawn sketches through the post if you do not have the facility to scan your image. Your
name, address and registration email address must be sent along with your sketch, preferably written on the reverse.
Also any notes or other information should be included with the sketch.
Postal entries
The Brief Competition
The Studios
Mansell Road
Wellington
Shropshire
TF1 1QQ
BRIEF:
THE SECOND DARTFORD BRIDGE CROSSING
LOCATION:
Across the River Thames between West Thurrock and Dartford to the east of London
Extra downloads
SketchUp and Google Earth
To enable you to use these powerful creative tools you will need to download both SketchUp and Google Earth and in
order to get the very best results and to submit the most visually appealing work we recommend that you follow some of
these tips;
•
When using Google Earth be sure to have the terrains option ticked, this will allow you to view the terrain on which
you will build in its most realistic view. Once you have that ticked use the rotate, zoom and tilt controls to view the site
and its surrounding area.
•
Before you export your selected view make sure that you have tilted the Google Earth view so that you looking at the
site from a "top down" perspective. This will ensure that you take the truest view of your site into SketchUp.
•
Before you start creating your SketchUp model on top of your chosen Google Earth view or before you place your
completed SketchUp model onto your Google Earth view make sure that you have the "terrains" turned on in
SketchUp. This will allow you to place your model on the ground and not beneath it, so that when you send your
completed model back to Google Earth that it is not vertically land locked.
Download SketchUp
Download the free version or pro version of SketchUp to create your Sketch at www.sketchup.com
Download Google Earth
Make sure that you have the latest release of Google Earth, download it from http://earth.google.com/download-earth.html