Dennis L. Edwards Tunnel Constructability Review February 5, 2010 East Portal looking west circa 2001 Nathan K. Potter, PE Project Manager Oregon Department of Transportation Randy G. Hinderer, PE Senior Project Manager LOCHNER East Portal looking west circa 1940

Agenda Introduction Project Overview Constructability Review Agenda

Dennis 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 Data US26 (Sunset) (Highway No. 047) Mile point: 40.9 Bridge No. 02552 Posted Speed: 55 MPH Average Daily Traffic (ADT): 6,700 Average Daily Truck Traffic (ADTT): 12% (804)

Dennis Edwards Tunnel (MP 40.90)

Project Objectives Reline the tunnel Lighting Improvements Drainage Improvements Freight industry has asked to ODOT to consider vertical improvements Bicycle/Pedestrian Improvements

Historic Considerations The completed masonry portal Model of the West Portal The builders East Portal looking west

Local Tunnel Detour Timber Road Oregon 47 Columbia County Washington County Oregon 47 Length Restricted 65’ Truck-tractor and Semi-trailer Total Detour Route = 26 Miles Distance on US 26 = 11 Miles Additional Distance = 15 Miles Timber Road 10 miles 16 Miles OR 47 1 11 Miles 2 Dennis Edwards Tunnel (MP 40.90) 1 Tillamook Railroad Over Crossing (MP 42.50) 2

Regional Detours (Seaside to I-405) US 30 = 115 Miles US 26 = 79 Miles Difference 36 Miles

Tunnel Profile

Edwards Tunnel, West Portal, March 2000

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Edwards Tunnel, East Portal, March 2000

Edwards Tunnel, Looking East from East Portal, March 2000

Edwards Tunnel, North Side of East Portal, March 2000

System Drainage

Alternative 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.

Alternative 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.

Alternative 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.

Constructability Review Agenda GOAL: 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

Tunnel Profile