Seattle’s Problem: Replacing the Viaduct

As we all know, the Viaduct must eventually be torn down.

There have been three proposals to deal with

this problem

• Build a new Viaduct• Build a tunnel• Replace the Viaduct with a surface road

Two of these methods are very costly.

• Costly Construction by 2009– Viaduct replacement: $3.0 Billion– Tunnel-Bulkhead: $4.9 Billion

• Costly Disruption– Waterfront commerce shut down

And the surface road option?

• doesn’t make any sense for traffic flow

• doesn’t make any sense for commerce

We submit that there is another way to replace the

Viaduct

The benefits of this method include

• Affordable Construction: $3.8 Billion*

• Very little downtown disruption

• Arterial flow maintained throughout the project

• No land acquisition required

*Based on current FST modular type construction methods from 1993 European source data. Data extrapolated to present day Washington State costs.

Engineering criteria, and technology have

been developed

• There are several ongoing engineering projects, and there are construction projects using this technology.

A proposal

We propose that the FHWA, WSDOT, and the City of Seattle, jointly fund an engineering

and cost feasibility study based on the following concept.

The ELLIOT BAY

SUBMERGED FLOATING TUNNEL

Like a floating bridge

The ELLIOT BAYSUBMERGED

FLOATING TUNNEL (EBSFT) is

anchored to the bottom.

Unlike a floating bridge

EBSFT is protected from storms

Like a tunnel

EBSFT uses traditional tunnel ventilation methods

South entranceventilation and

service structure

Unlike a tunnel

EBSFT requires minimal digging and commercial disruption.

Like a traditional suspension bridge

EBSFT issuspended.(off of the bottom)

Unlike a traditional suspension bridge

EBSFT is in an environment

where loads are substantially

less than bridges.

In this example we propose building the EBSFT using plastic composite methods

• Not like modular construction STF approach used to date.

• Flexible mono-structure– eliminates joints under water– can be towed into place– flexible enough to handle underwater and seismic

stresses – recycled flotation and ballast components can be

used

Step1

• Build a facility on the northern tip of Harbor Island

Step 2

• Weave cables, or other appropriate materials to create flexible tube tunnel structures.

• These tunnel structures are coated and covered with a flexible composite.

Step 3

• Install deck beams. These beams act as foundation for the road beds.

Step 4

• Add additional structural components• Build a composite filler with integral structural

flotation and ballast. (This filler connects the tunnels)

Step 5

• As EBSFT is constructed, it is flooded and towed into place with tugs.

Step 6

• EBSFT is anchored to the bottom and supplied with enough positive buoyancy to support the weight of traffic

EBSFT cross section

South boundBallast tanks,bilges and pumps

Service and ventilation

Bilges

Integral composite flotationNorth bound

Integral composite ballast

More Commerce

Other submerged floating tunnels could be produced at the Harbor

Island facility, and be towed to site.

EBSFT Placement Options

EBSFT starts at Harbor Island

It could startat other

locations too

Recap

• The benefits of Submerged Floating Tunnel Technology in Seattle– Affordable– Very little downtown disruption– Arterial flow maintained – No land acquisition required– New industry for the region

• The technology is ready and waiting

We Request that the FHWA, WSDOT, and

the City of Seattle

jointly fund an engineering and cost feasibility study for the

ELLIOT BAY SUBMERGED FLOATING TUNNEL

Source Documents

• http://www.fehrl.org/?m=32&id_directory=58– including: Forum of European National Highway Research

Laboratories Analysis of the submerged floating tunnel concept, Transport Research Laboratory Crowthorne, Berkshire, RG45 6AU, 1996 p10

• http://www.wsdot.wa.gov/BIZ/CONSTRUCTION/CostIndex/CostIndexPd f/constructioncosts.pdf

• http://seattlepi.nwsource.com/transportation/285955_viaduct21.html• http://www.fhwa.dot.gov/bridge/frp/frp1298.cfm• http://www.jeico.co.kr/cnc57ec1.html• http://www.wsdot.wa.gov/Projects/SR520Bridge/Photos/Damage.htm• http://testcf.wsdot.wa.gov/projects/sr16narrowsbridge/photolibrary/19

40/enlarged/?image=1940_2.jpg&description=desc2.htm• http://www.fhwa.dot.gov/bigdig.htm

EBSFT

Sometimes ideas just need to get out there!

Art & Invention focuses on creative consultancy and mechanical product development.Contact: Mark Adams, artandinvention@clearwire.net

P.O. Box 11278 Bainbridge Island, WA 98110

EBSFT

THANK YOU