Wednesday, February 1, 2017

US-67 Old and New Bridge over Mississippi River in Alton, IL

(Bridge Hunter Old, Bridge Hunter New, no Historic Bridges, John Weeks III New, PBS Nova TranscriptBirds-Eye View)

HAER IL-31-36 from IL0555
DETAIL VIEW OF HIGHWAY BRIDGE, SHOWING RAILROAD BRIDGE AND LOCK AND DAM IN BACKGROUND, LOOKING NORTHEAST (UPSTREAM) 

HAER IL-31-37 from IL0555
DETAIL VIEW OF HIGHWAY BRIDGE, SHOWING RAILROAD BRIDGE AND LOCK AND DAM IN BACKGROUND, LOOKING NORTHEAST (UPSTREAM) 

This bridge was replaced not only because more traffic and pedestrian/bike lanes were needed, but the spans were short and presented a significant navigation hazard after the new #26 Lock and Dam was built.

John Weeks III
John explains that this bridge is unusual because cables from both sides use the same tower.

John Weeks III
John explains that it is also unusual because all of the cables go over a saddle on top of the tower rather than attach to the sides of  the tower. "While this is an innovative design, the saddle design has proven to have a serious problem, and is not likely to be attempted again in the near future." (I could not find any details on the problem.)
The new Tappan Zee Bridge is an example of the more traditional H tower design where each cable attaches to the side of the tower. (Although I think the flaring outwards of the H is a new wrinkle of the cable-stay design.)

New York State Thruway Authority from hdrinc

20150509 1066c
Parallel towers being built for the new I-65 bridge at Louisville, KY
Often called the "Super Bridge," the Clark Bridge links Highways 367 and 67 in Missouri to Alton, Illinois. It replaced the old Clark Bridge that served the area from 1928 to 1994. Design work on the new cable-stayed bridge was started in 1985, and construction began in 1990. The bridge, which has four traffic lanes and two bike lanes, spans 4,260 feet across the Mississippi River. It is made of 8,100 tons of structural steel, 44,100 cubic yards of concrete and more than 160 miles of cable wrapped with four acres of yellow plastic piping. Pilings that support the bridge were driven more than 140 feet below bedrock. Design criteria based on wind testing and geological studies were used to help make the bridge earthquake resistant. Total cost of the bridge was 118 million dollars, including the demolition of the old bridge. [GreatRiverRoad]
Update:  During the 2017 flood, water covered the fixed part of the dam and was on part of the road on the levee on the MO side. On the Illinois side, the Great River Road and railroad by the bluffs were under water. And water was up to the mill.
Screenshot from 5/4/2017 video posted by KMOV
It turns out, quite a bit of this area is under water at normal river levels.
Birds-Eye View

No comments:

Post a Comment