Fort McHenry Tunnel - Construction

Fort McHenry Tunnel - Construction - 1983

The following 20 photos are of various stages of the construction of the Fort McHenry Tunnel in Baltimore, Maryland.

Click the small image to link to a larger image (they range from 90K to 180K).

This group of 11 photos was taken of the West Approach construction, on same day in February 1983, in the same photo session.

	West end of the sunken tubes, and west approach construction. This is on the Locust Point Peninsula. A trench has been excavated for cut-and-cover tunnel construction.
	West end of the sunken tubes, and west approach construction.
	West end of the sunken tubes, and west approach construction.
	Gravity slabs are being constructed in the foreground, and cut-and-cover tunnel is being constructed in the background.
	Gravity slabs are being constructed in foreground, and cut-and-cover tunnel is being constructed in the background. Same vantage point as previous photo, but with a 135mm (2.7x) telephoto lens instead of the 50 mm (1.0x) regular lens used in the previous photo.
	Cut-and-cover tunnel is being constructed in the background.
	Cut-and-cover tunnel is being constructed. West end of the sunken tubes is in background.
	Cut-and-cover tunnel is being constructed. West end of the sunken tubes is in background. Same vantage point as previous photo, but with a 135mm (2.7x) telephoto lens instead of the 50 mm (1.0x) regular lens used in the previous photo.
	Cut-and-cover tunnel is being constructed. West end of the sunken tubes is in the background.
	Elevated viaduct construction. Much of I-95 on the Locust Point Peninsula is on elevated bridge structure. This is looking west, and the viaduct will transition to ground level near where I am standing, and then the roadways will descend below ground level into the West Approach and then to the Fort McHenry Tunnel portals.
	West approach construction. Near where the West Approach begins at ground level, looking east toward excavation underway to build the depressed approaches to the tunnel.

The Fort McHenry Tunnel construction method is described in detail in this linked document: Construction of I-95 Fort McHenry Tunnel, Baltimore, Maryland, by Maryland Department of Transportation, and City of Baltimore, and U.S. Department of Transportation. This six-page folder was widely distributed to the public while the project was under construction. I utilized Adobe Acrobat 5.0 to create the .pdf document. The resolution is a tad lacking in a few places, but overall the document reproduced fairly well, and at 1,789 KB, it is large but a lot smaller than if I had scanned it as images. The files are in Adobe Acrobat format. If you do not have Adobe Acrobat Reader, please click here to download a free copy of the program.

The 5,400-foot-long immersed tube portion of the Fort McHenry Tunnel was built with the same construction method as that of the Ted Williams Tunnel in Boston, which was opened to traffic in 1995. The Central Artery/Tunnel Project - Ted Williams Tunnel website has a detailed description of the immersed tube construction method on the page CA/T Project - Ted Williams Tunnel - How was it built?

Excellence in Highway Design - Ted Williams Tunnel, Category 1 - Urban Highways Award of Merit, Federal Highway Administration, 1996. Quote (blue text): The Ted Williams Tunnel doubles Boston's traffic capacity under Boston Harbor to Logan Airport from four lanes to eight. The 2.6 km (1.6 mile), $1.3 billion tunnel, includes a 1.2 km (3/4 mile) underwater section consisting of tubes placed in a trench dredged on the harbor floor. The tunnel was initially only opened to commercial traffic while local highway connections are completed. When the connection to the Massachusetts Turnpike is finished (expected in 2001) the tunnel will complete 1-90 from coast to coast.

This group of 9 photos taken of the East Approach and West Approach construction, on same day in July 1983, in the same photo session.

East Approach construction. Looking east toward toll plaza construction. I-95 rises onto an elevated viaduct, visible in the top left of the photo. The existing viaduct in the top right of the photo is the Harbor Tunnel Thruway.

East Approach construction. East end of the sunken tubes.

West approach construction. I'm standing on top of the constructed cut-and-cover tunnel, looking west. Open approaches are visible in the distance. The tunnel portal is just beyond the red crane.

West approach construction. I'm standing on top of the constructed cut-and-cover tunnel, looking west. Open approaches are visible in the distance. The tunnel portal is just beyond the red crane. Same vantage point as previous photo, but with a 135mm (2.7x) telephoto lens instead of the 50 mm (1.0x) lens used in previous photo. I-95 grade rises upward from the tunnel portal, and continues to rise up onto the elevated viaduct visible in the distance.

West approach construction. Similar vantage point to previous photo, but standing over eastbound tunnels (in previous photo I am standing over the westbound tunnels). Notice the concrete gravity slabs as they get thicker as the roadway descends downward toward the tunnel; the one on the right is close to where the roadway will be, and the Jersey Barrier roadside barrier is visible at the right edge of the gravity slab.

West approach construction. This presently open space is between the four cut-and-cover tunnels and the sunken tube tunnels, and the west ventilation building and its foundation structures will be constructed in the open space.

West approach construction. Cut-and-cover tunnel is being constructed. West end of the sunken tubes is in the background. I'm standing on top of the constructed tunnel, near the portal of the cut-and-cover tunnel (the portal is just behind me).

West end of the sunken tubes, and west approach construction. Cut-and-cover tunnel construction and and construction of the foundations of the west ventilation building is underway near the connection to the sunken tubes. Fort McHenry is in the background.

West end of the sunken tubes, and west approach construction. Cut-and-cover tunnel construction and construction of the foundations of the west ventilation building is underway near the connection to the sunken tubes.

Notice the massive concrete gravity slabs under construction in some of the photos. They will range from 7 to 20 feet thick, designed to resist the hydrostatic pressure below sea level; the thickness increases as the tunnel grade slopes downward toward the harbor, reaching about 30 feet below sea level where the sunken tube tunnel begins. The gravity slabs extend for the full width of the approach tunnel and open depressed approach, and they literally serve as an "anchor" by providing enough weight to prevent the structure from "floating" upward from the pressure of the ground water. The I-395 Mall Tunnel in the District of Columbia and the I-95 "bathtub" project in downtown Philadelphia used gravity slabs too, for the same reasons, where tunnels and open approaches were below sea level.

Next: Fort McHenry Tunnel - Construction - 1984

All photos taken by Scott Kozel.

Copyright © 2003 by Scott Kozel. All rights reserved. Reproduction, reuse, or distribution without permission is prohibited.

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By Scott M. Kozel, Roads to the Future

(Created 1-1-2003)

	East Approach construction. Looking east toward toll plaza construction. I-95 rises onto an elevated viaduct, visible in the top left of the photo. The existing viaduct in the top right of the photo is the Harbor Tunnel Thruway.
	East Approach construction. East end of the sunken tubes.
	West approach construction. I'm standing on top of the constructed cut-and-cover tunnel, looking west. Open approaches are visible in the distance. The tunnel portal is just beyond the red crane.
	West approach construction. I'm standing on top of the constructed cut-and-cover tunnel, looking west. Open approaches are visible in the distance. The tunnel portal is just beyond the red crane. Same vantage point as previous photo, but with a 135mm (2.7x) telephoto lens instead of the 50 mm (1.0x) lens used in previous photo. I-95 grade rises upward from the tunnel portal, and continues to rise up onto the elevated viaduct visible in the distance.
	West approach construction. Similar vantage point to previous photo, but standing over eastbound tunnels (in previous photo I am standing over the westbound tunnels). Notice the concrete gravity slabs as they get thicker as the roadway descends downward toward the tunnel; the one on the right is close to where the roadway will be, and the Jersey Barrier roadside barrier is visible at the right edge of the gravity slab.
	West approach construction. This presently open space is between the four cut-and-cover tunnels and the sunken tube tunnels, and the west ventilation building and its foundation structures will be constructed in the open space.
	West approach construction. Cut-and-cover tunnel is being constructed. West end of the sunken tubes is in the background. I'm standing on top of the constructed tunnel, near the portal of the cut-and-cover tunnel (the portal is just behind me).
	West end of the sunken tubes, and west approach construction. Cut-and-cover tunnel construction and and construction of the foundations of the west ventilation building is underway near the connection to the sunken tubes. Fort McHenry is in the background.
	West end of the sunken tubes, and west approach construction. Cut-and-cover tunnel construction and construction of the foundations of the west ventilation building is underway near the connection to the sunken tubes.