Tower caisson for the Mackinac Bridge (36 of 45)

Adding the next double walled steel ring.  As rings were added the space between the two walls was filled with aggregate and the center was dredged.  This action caused the caisson to cut its way through the overburden and eventually reach bedrock.  Aggregate was added where needed to keep the caisson  plumb as it descended.., Electronic reproduction of photograph.  The Mackinac Bridge 1954 - 1958. Mackinac Bridge Authority
Abstract/Description: Adding the next double walled steel ring. As rings were added the space between the two walls was filled with aggregate and the center was dredged. This action caused the caisson to cut its way through the overburden and eventually reach bedrock. Aggregate was added where needed to keep the caisson plumb as it descended..
Subject(s): Bridges--Design and construction
St. Ignace (Mich.)
Mackinaw City (Mich.)
Mackinac Bridge (Mich.)
Date Created: 1954 (approximate)