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| Location of The Straits of Mackinac |
The Straights of Mackinac are a narrow, relatively shallow waterway connecting Lake Huron and Lake Michigan. The shortest distance across the Straits from Michigan’s Lower Peninsula to the Upper Peninsula (UP) is about five miles. It’s across this stretch of water that The Mackinac Bridge was built.
During the seventieth, eighteenth, and nineteenth centuries, people traveling from one peninsula to the other used canoes or boats to cross. The crossing was dangerous and during winter, almost impossible until the waterway completely froze over.
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| Algonquin Indians in dugout |
As early as 1880, Michigan Legislators began discussing the construction of a bridge spanning the Straits of Mackinac. Then in July 1888, on Mackinac Island, during a meeting of the board of directors of the Grand Hotel, Cornelius Vanderbilt II introduced a plan to build bridge across the Straits. His goal was to expand business in the area and help lengthen the resort season of his hotel. The design he proposed was similar to one under construction across the Firth of Forth in Scotland. Though plans for a bridge were ahead of their time, ways to make crossing the waterway more efficient continued to pass through Michigan Legislation and discussed among local businesses.
By 1923 cars had become common place in the United States. The Michigan State Highway Department began a car ferry system to transport people and their vehicles across the Straits. As the ferry system became more popular it
also became more expensive for the state to maintain.
After only five years of ferry service, Governor Fred Green ordered that the same agency that ran the ferry system to research the possibility of building a bridge. Their findings were positive. The estimated cost was 30 million dollars. There were steps taken to get the project underway but soon the project was dropped until 1934 when Michigan Legislature formed the Mackinac Straits Bridge Authority of Michigan.
At this time, The Bridge Authority conducted another study of bridge feasibility. Their findings were similar to the 1923 study, and it was concluded that the bridge could be built for approximately 32,400,000.
For the next ten years the Mackinac Straits Bridge Authority worked diligently to raise funds and obtain federal grants, but unfortunately due, in part, to World War Two, the Bridge Authority was abolished and all plans for a bridge across the Straits were put on hold.
Soon after the war ended The Mackinac Bridge Authority of Michigan was reinstated and exists to this day. It took another ten years of fundraising and planning before bridge construction took place. Ground breaking ceremonies were held on May 7th, 1956 in Saint Ignace (Upper Peninsula side) and on May 8th in Mackinaw City (Lower Peninsula side).
Mackinac Bridge construction began with the erecting the pillars. Caissons (footing) were built off site then floated into position and sunk to provide a foundation for the two main towers. Cables would be connected to the two towers and would serve to support the center span of the bridge. Creeper derricks (crane type machines) were added, to raise materials for construction. Truss sections were built in sections and floated into position then raised into place.
Right on schedule, the Mackinac Bridge opened to traffic on November 1, 1957. The auto ferry service discontinued runs on the same day. On June 25, 1958, the Bridge was formally dedicated.
The following facts and figures are quoted from David Steinman's book "Miracle Bridge at Mackinac".
LENGTHS
Total Length of Bridge (5 Miles) - 26,372 Ft.
Total Length of Steel Superstructure - 19,243 Ft.
Length of Suspension Bridge (including Anchorages) - 8,614 Ft.
Total Length of North Approach - 7,129 Ft.
Length of Main Span (between Main Towers) - 3,800 Ft.
HEIGHTS AND DEPTHS
Height of Main Towers above Water - 552 Ft
Maximum Depth to Rock at Midspan - Unknown
Maximum Depth of Water at Midspan - 295 Ft.
Maximum Depth of Tower Piers below Water - 210 Ft.
Height of Roadway above Water at Midspan - 199 Ft.
Under-clearance at Midspan for Ships - 155 Ft.
Maximum Depth of Water at Piers - 142 Ft.
Maximum Depth of Piers Sunk through Overburden - 105 Ft.
CABLES
Total Length of Wire in Main Cables - 42,000 Miles
Maximum Tension in Each Cable - 16,000 Tons
Number of Wires in Each Cable - 12,580
Weight of Cables - 11,840 Tons
Diameter of Main Cables - 24 1/2 Inches
Diameter of Each Wire - 0.196 Inches
WEIGHTS
Total Weight of Bridge - 1,024,500 Tons
Total Weight of Concrete - 931,000 Tons
Total Weight of Substructure - 919,100 Tons
Total Weight of Two Anchorages - 360,380 Tons
Total Weight of Two Main Piers - 318,000 Tons
Total Weight of Superstructure - 104,400 Tons
Total Weight of Structural Steel - 71,300 Tons
Weight of Steel in Each Main Tower - 6,500 Tons
Total Weight of Cable Wire - 11,840 Tons
Total Weight of Concrete Roadway - 6,660 Tons
Total Weight of Reinforcing Steel - 3,700 Tons
RIVETS AND BOLTS
Total Number of Steel Rivets - 4,851,700
Total Number of Steel Bolts - 1,016,600
DESIGN AND DETAIL DRAWINGS
Total Number of Engineering Drawings - 4,000
Total Number of Blueprints - 85,000
MEN EMPLOYED
Total, at the Bridge Site - 3,500
At Quarries, Shops, Mills, etc. - 7,500
Total Number of Engineers - 350
IMPORTANT DATES
Mackinac Bridge Authority Appointed - June 1950
Board of Three Engineers Retained - June 1950
Report of Board of Engineers - January 1951
Financing and Construction Authorized by Legislature - April 30, 1952
D.B. Steinman Selected as Engineer - January 1953
Preliminary Plans and Estimates Completed - March 1953
Construction Contracts Negotiated - March 1953
Bids Received for Sale of Bonds - December 17, 1953
Began Construction - May 7, 1954
Open to traffic - November 1, 1957
Formal dedication - June 25-28, 1958
50 millionth crossing - September 25, 1984
40th Anniversary Celebration - November 1, 1997
100 millionth crossing - June 25, 1998
By 1923 cars had become common place in the United States. The Michigan State Highway Department began a car ferry system to transport people and their vehicles across the Straits. As the ferry system became more popular it
also became more expensive for the state to maintain.
At this time, The Bridge Authority conducted another study of bridge feasibility. Their findings were similar to the 1923 study, and it was concluded that the bridge could be built for approximately 32,400,000.
For the next ten years the Mackinac Straits Bridge Authority worked diligently to raise funds and obtain federal grants, but unfortunately due, in part, to World War Two, the Bridge Authority was abolished and all plans for a bridge across the Straits were put on hold.
Soon after the war ended The Mackinac Bridge Authority of Michigan was reinstated and exists to this day. It took another ten years of fundraising and planning before bridge construction took place. Ground breaking ceremonies were held on May 7th, 1956 in Saint Ignace (Upper Peninsula side) and on May 8th in Mackinaw City (Lower Peninsula side).
Mackinac Bridge construction began with the erecting the pillars. Caissons (footing) were built off site then floated into position and sunk to provide a foundation for the two main towers. Cables would be connected to the two towers and would serve to support the center span of the bridge. Creeper derricks (crane type machines) were added, to raise materials for construction. Truss sections were built in sections and floated into position then raised into place.
Right on schedule, the Mackinac Bridge opened to traffic on November 1, 1957. The auto ferry service discontinued runs on the same day. On June 25, 1958, the Bridge was formally dedicated.
The following facts and figures are quoted from David Steinman's book "Miracle Bridge at Mackinac".
LENGTHS
Total Length of Bridge (5 Miles) - 26,372 Ft.
Total Length of Steel Superstructure - 19,243 Ft.
Length of Suspension Bridge (including Anchorages) - 8,614 Ft.
Total Length of North Approach - 7,129 Ft.
Length of Main Span (between Main Towers) - 3,800 Ft.
HEIGHTS AND DEPTHS
Height of Main Towers above Water - 552 Ft
Maximum Depth to Rock at Midspan - Unknown
Maximum Depth of Water at Midspan - 295 Ft.
Maximum Depth of Tower Piers below Water - 210 Ft.
Height of Roadway above Water at Midspan - 199 Ft.
Under-clearance at Midspan for Ships - 155 Ft.
Maximum Depth of Water at Piers - 142 Ft.
Maximum Depth of Piers Sunk through Overburden - 105 Ft.
CABLES
Total Length of Wire in Main Cables - 42,000 Miles
Maximum Tension in Each Cable - 16,000 Tons
Number of Wires in Each Cable - 12,580
Weight of Cables - 11,840 Tons
Diameter of Main Cables - 24 1/2 Inches
Diameter of Each Wire - 0.196 Inches
WEIGHTS
Total Weight of Bridge - 1,024,500 Tons
Total Weight of Concrete - 931,000 Tons
Total Weight of Substructure - 919,100 Tons
Total Weight of Two Anchorages - 360,380 Tons
Total Weight of Two Main Piers - 318,000 Tons
Total Weight of Superstructure - 104,400 Tons
Total Weight of Structural Steel - 71,300 Tons
Weight of Steel in Each Main Tower - 6,500 Tons
Total Weight of Cable Wire - 11,840 Tons
Total Weight of Concrete Roadway - 6,660 Tons
Total Weight of Reinforcing Steel - 3,700 Tons
RIVETS AND BOLTS
Total Number of Steel Rivets - 4,851,700
Total Number of Steel Bolts - 1,016,600
DESIGN AND DETAIL DRAWINGS
Total Number of Engineering Drawings - 4,000
Total Number of Blueprints - 85,000
MEN EMPLOYED
Total, at the Bridge Site - 3,500
At Quarries, Shops, Mills, etc. - 7,500
Total Number of Engineers - 350
IMPORTANT DATES
Mackinac Bridge Authority Appointed - June 1950
Board of Three Engineers Retained - June 1950
Report of Board of Engineers - January 1951
Financing and Construction Authorized by Legislature - April 30, 1952
D.B. Steinman Selected as Engineer - January 1953
Preliminary Plans and Estimates Completed - March 1953
Construction Contracts Negotiated - March 1953
Bids Received for Sale of Bonds - December 17, 1953
Began Construction - May 7, 1954
Open to traffic - November 1, 1957
Formal dedication - June 25-28, 1958
50 millionth crossing - September 25, 1984
40th Anniversary Celebration - November 1, 1997
100 millionth crossing - June 25, 1998
Thank you for joining me here at Hero, Heroines, and History.
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Award
winning author, Michele Morris’s
love for historical fiction began when she first read Laura Ingalls Wilder’s
Little House book series. She grew up riding horses and spending her free time
in the woods of mid-Michigan dreaming of days-gone-by
and knights-in-shining-armor. Therefore, it only makes sense that she now
writes historical romance with a touch of suspense. Married to her high school
sweetheart, they are living happily-ever-after with their six children, three
in-loves, and six grandchildren in Florida, the sunshine state. When not
spending time with her large brood or writing,
Michele enjoys photography, genealogy, and cooking.
Interesting history about the Mackinac Bridge. A friend who grew up there has shared her stories with me, which I've enjoyed.
ReplyDeleteThank you for the comment, Marilyn. It's a beautiful bridge, although a little scary to cross!
ReplyDelete