Portage Lake Lift Bridge
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| Official name | Portage Lake Lift Bridge |
| Carries | US 41 and M-26 |
| Crosses | Portage Waterway arm of Portage Lake |
| Locale | Hancock and Houghton, Michigan |
| Maintained by | MDOT |
| Design | Vertical Lift Bridge |
| Longest span | 250 ft (76 m) clearance |
| Total length | approx 500 feet (150 m) |
| Width | upper deck: - 4 lanes with no shoulders lower deck: - 4 lanes with no shoulders - single track railroad (abandoned 1982) |
| Clearance below | 4 ft (1.2 m) fully lowered, 32-36 ft raised to intermediate position (lower deck at upper roadway), about 100 ft (30 m) fully raised) |
| Opening date | 1875, 1901, 1959(current) |
| Coordinates | 47°07′26″N 88°34′29″W / 47.123768°N -88.574706°ECoordinates: 47°07′26″N 88°34′29″W / 47.123768°N -88.574706°E |
The Portage Lake Lift Bridge connects the cities of Hancock and Houghton, Michigan, USA, across Portage Lake, a portion of the waterway which cuts across the Keweenaw Peninsula with a canal linking the final several miles to Lake Superior to the northwest. US 41 and M-26 are both routed across the bridge.
The original bridge on this site was a wooden swing-bridge built in 1875. This was replaced by a steel swing-bridge built by the King Bridge Company in 1901. This bridge was damaged when a ship collided with it in 1905. The center swinging section of the bridge was replaced and a similar incident almost occurred again in 1920, but the ship was able to stop by dropping its anchor, which snagged on the bottom of the lake. In 1959, this bridge was replaced, at a cost of about 11-13 million US dollars (sources vary), by the current bridge which was built by the American Bridge Company.[1]
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As its name states, the bridge is a lift bridge with the middle section capable of being lifted from its low point of four feet clearance over the water to a clearance of 100 feet (30 m) to allow boats to pass underneath. The Bridge is the world's heaviest and widest double-decked vertical lift bridge.[2] Its center span "lifts" to provide 100 feet (30 m) of clearance for ships. The bridge is a crucial lifeline, since it is the only land based link between the north (so-called Copper Island) and south sections of the Keweenaw peninsula.[3]
The lower deck of the bridge was originally open to rail traffic, but this level is now a road and it is raised up to road level in the summer for cars. This is done so that smaller boats may pass below without needing to disrupt car traffic. It is lowered in the winter, when ice prevents boats, so that snowmobile traffic that can enter under the roadway.
Hancock and Houghton hold an annual celebration called Bridgefest to commemorate the opening of the bridge which united their two communities.[4]
[edit] Notes
[edit] External links
- Michigan Tech Bridge Cam
- Portage Lake BridgeCam
- Bridgefest Website
- Aerial photo of bridge, from Microsoft Terraserver
- City of Hancock Bridge History Page
- King Bridge Company older bridge history page
- Byways.org Claims bridge is heaviest/widest double deck lift bridge in world.
- Michigan Department of Transportation page
- Copper Range historical society information
