Testing for Mackinac Bridge construction (3 of 3)

Core drills were used to check the concrete within the pier, Electronic reproduction of photograph.  The Mackinac Bridge 1954 - 1958. Mackinac Bridge Authority
Abstract/Description: Core drills were used to check the concrete within the pier
Subject(s): Bridges--Design and construction
St. Ignace (Mich.)
Mackinaw City (Mich.)
Mackinac Bridge (Mich.)
Date Created: 1955 (approximate)