1

Dennis L. Edwards Dennis L. Edwards TunnelTunnel

Constructability ReviewFebruary 5, 2010

East Portal looking west circa 1940

East Portal looking west circa 2001

Nathan K. Potter, PEProject Manager

Oregon Department of Transportation

Randy G. Hinderer, PESenior Project Manager

LOCHNER

2

AgendaAgenda

• Introduction • Project Overview • Constructability Review Agenda

3

Dennis L. Edwards TunnelDennis L. Edwards Tunnel

Originally called the Sunset Tunnel, construction was completed by the Works Progress Administration (WPA) in 1940.

The tunnel was renamed after Dennis Edwards, a member of the District 2A staff who was killed during inspection activities in January 1999 when part of the tunnel collapsed. Closure and detour duration was approximately 5 weeks.

Technical DataUS26 (Sunset) (Highway No. 047)Mile point: 40.9Bridge No. 02552Posted Speed: 55 MPHAverage Daily Traffic (ADT): 6,700Average Daily Truck Traffic (ADTT): 12% (804)

4

Dennis Edwards Tunnel(MP 40.90)

5

Project ObjectivesProject Objectives

• Reline the tunnel• Lighting Improvements• Drainage Improvements• Freight industry has asked to ODOT

to consider vertical improvements• Bicycle/Pedestrian Improvements

6

Historic ConsiderationsHistoric ConsiderationsModel of the West Portal

The builders

East Portal looking west

The completed masonry portal

7

1

2

Tillamook Railroad Over Crossing (MP 42.50)

Dennis EdwardsTunnel(MP 40.90)

Tim

ber

Ro

ad10

mile

s

11 Miles

OR

47

16 Miles

Timber RoadColumbia CountyWashington County

Oregon 47Length Restricted65’ Truck-tractor and Semi-trailer

Total Detour Route = 26 MilesDistance on US 26 = 11 Miles

Additional Distance = 15 Miles

Local Tunnel DetourLocal Tunnel Detour

1

2

8

Regional DetoursRegional Detours (Seaside to I-405)(Seaside to I-405)

US 26 = 79 MilesUS 30 = 115

Miles

Difference 36 Miles

9

Tunnel ProfileTunnel Profile

10Edwards Tunnel, West Portal, March 2000

11Edwards Tunnel, STA 0+00 Looking East, March 2000

12Edwards Tunnel, STA 0+50 Looking East, March 2000

13Edwards Tunnel, STA 1+00 Looking East, March 2000

14Edwards Tunnel, STA 1+50 Looking East, March 2000

15Edwards Tunnel, STA 2+00 Looking East, March 2000

16Edwards Tunnel, STA 2+50 Looking East, March 2000

17Edwards Tunnel, STA 3+00 Looking East, March 2000

18Edwards Tunnel, STA 3+50 Looking East, March 2000

19Edwards Tunnel, STA 4+00 Looking East, March 2000

20Edwards Tunnel, STA 4+50 Looking East, March 2000

21Edwards Tunnel, STA 5+00 Looking East, March 2000

22Edwards Tunnel, STA 5+50 Looking East, March 2000

23Edwards Tunnel, STA 6+00 Looking East, March 2000

24Edwards Tunnel, STA 6+50 Looking East, March 2000

25Edwards Tunnel, STA 7+00 Looking East, March 2000

26Edwards Tunnel, STA 7+71.5 North Side, March 2000

27Edwards Tunnel, East Portal, March 2000

28Edwards Tunnel, Looking East from East Portal, March 2000

29Edwards Tunnel, North Side of East Portal, March 2000

30

System DrainageSystem Drainage

31

Alternative 1: Lining OnlyAlternative 1: Lining Only

• Replaces the tunnel lining• Replaces / rehabilitates the tunnel PCC floor

and drainage system• Installs new lighting system • Existing portals and stone masonry will remain

untouched.

32

Alternative 2: Floor LoweringAlternative 2: Floor Lowering

• Clearance achieved by removing the existing lining consisting of steel and timber sets, removing the rubble and gravel behind the existing liner, and replacing the liner with rock bolted shotcrete directly to the exposed siltstone bedrock.

• Roadway elevation will be lowered throughout the tunnel approximately 2.5 feet to achieve vertical clearance, transitioning back to existing grade approximately 700 feet on both tunnel approach sections.

• Existing portals and stone masonry will remain intact, however underpinning the portal masonry and associated concrete wall structure with new footings will be necessary.

33

Alternative 3: Portal RaisingAlternative 3: Portal Raising

• Clearance achieved by removing the existing lining consisting of steel and timber sets, removing the rubble and gravel behind the existing liner, and replacing the liner with rock bolted shotcrete directly to the exposed siltstone bedrock.

• Existing portals will be raised approximately 2.5 feet to achieve vertical clearance.

• RequireS specialized work for the historic portal stone masonry, which will be removed and replaced on a new portal wall structure at a higher elevation.

34

Constructability Review AgendaConstructability Review AgendaGOAL: What is the highway closure duration?

• Equipment– Dimensions– Location– What equipment will be

required to raise the portals, excavate, etc., will it fit in the tunnel

• Methods – Contingency plans for

unknowns – Roadway undercutting– What protection / shoring

methods will be required for the portals?

– Lowering the tunnel floor and roadway:

– Historic Stone Portal Removal and Reconstruction

– Specialty work required to maintain material integrity during removal and reconstruction

– Timber Lining Demolition– Shotcrete Lining Demolition

• Materials– Concrete– Masonry materials – Historic Stone Portal

Underpinning• Staging

– Raising Portals– Re-Lining – Is it feasible to lower the

tunnel floor, construct temporary ties into existing roadway, and stage approach roadway construction with single lane closures?

– Is there any methodology to keep the highway partially open?

• Durations– Existing lining removal– Roadway lowering– Rising portals: reconstruction

verses lifting– Full closure versus partials

35

Tunnel ProfileTunnel Profile