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Upper Peninsula Regional Digitization Center

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  • All fields: Alpena
(8 results)



Display: 20

    • Tower caisson move

    • Mackinac Bridge (Mich) ; Bridges -- Design and construction
    • One of the completed tower caisson cutting (1st) section sits at the Alpena fabrication site while machinery digs a channel out to Lake Huron so the caisson can be towed by tug to the straights, 990 miles away
    • Caisson launch

    • Mackinac Bridge (Mich) ; Bridges -- Design and construction
    • The first section of the tower caissons were constructed at Alpena, MI, launched from the beach and towed by tugboat to the construction site 90 miles to the Northwest. The ""soil"" was so hard that dynamite was used to break it up so drag lines...
    • Tower caisson

    • Mackinac Bridge (Mich) ; Bridges -- Design and construction
    • Construction of the first section of a tower caisson. Note the wedge shaped cutting edge. These sections were fabricated in Gary, Indiana and shipped to Rockport (Alpena), MI by barge where they were assembled by Wiltse Brothers Shipyard. This...
    • Tower caisson

    • Mackinac Bridge (Mich) ; Bridges -- Design and construction
    • The first section of a tower caisson (caisson No. 20) is fabricated at Alpena, MI and ready to be towed to the construction site. But first a channel must be dug to Lake Huron (background).
    • Construction equipment

    • Mackinac Bridge (Mich) ; Bridges -- Design and construction
    • Merritt-Chapman & Scott marine construction equipment making a channel at Alpena, MI in order to float the first section of tower caisson No. 20 out of the assembly area and into Lake Huron for the 90 mile trip to the bridge site.
    • Tower caisson

    • Mackinac Bridge (Mich) ; Bridges -- Design and construction
    • Photo shows the cutting edge of the tower caisson No. 19 during fabrication at Alpena, MI. Designed to work like a cookie cutter this caisson is filled with aggregate in the double wall area which acts as weight to drive it through the...

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