Spring at pier no. 20 of the Mackinac Bridge (3 of 4)

Pumping grout at pier 20 caisson, Electronic reproduction of photograph.  The Mackinac Bridge 1954 - 1958. Mackinac Bridge Authority
Abstract/Description: Pumping grout at pier 20 caisson
Subject(s): Bridges--Design and construction
St. Ignace (Mich.)
Mackinaw City (Mich.)
Mackinac Bridge (Mich.)
Date Created: 1955 (approximate)