The Mackinac Bridge, or "Big Mac" (below), is one of the most impressive suspension bridges in the world. It is the "Great" susupension bridge. As the largest bridge of its type, this bridge is important in that it connects the two penninsulas of Michigan, and thereby provides an easier route for travel from any direction from the north or northwest by allowing a southernly route down Interstate 75.  Below are some statistics on this mighty engineering structure. See the links to web pages about the bridge in the "Related Links" part of the GEO 333 page.

LENGTHS
Total Length of Bridge: 5 Miles, or 26,372 feet
Total Length of Steel Superstructure: 19,243 feet
Length of Suspension Bridge (including Anchorages): 8,614 feet
Length of Main Span (between Main Towers): 3,800 feet

HEIGHTS AND DEPTHS
Height of Main Towers above Water: 552 feet
Maximum Depth to Solid Bedrock at Midspan: unknown
Maximum Depth of Water at Midspan: 295 feet
Maximum Depth of Tower Piers below Water: 210 feet
Height of Road above Water at Midspan: 199 feet
Underclearance at Midspan for Ships: 155 feet
Maximum Depth of Water at Piers: 142 feet

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

Source: Unknown

The Blue Water Bridge connects Port Huron, MI (left) with Sarnia, Ontario.Since 1938, this international bridge has served as the main artery of transportation across the St. Clair River. It also provides for one of the four shortest routes of land travel between the eastern seaboard and the central US. Today, another, more modern bridge stands next to the original Blue Water bridge. The new bridge is the one that carries traffic on I-69.

One of only two suspension bridges linking the United States and Canada, the Ambassador Bridge (below) spans the Detroit River between Detroit, Michigan and Windsor, Ontario. Only the center span is suspended from the main cables. The two side spans are supported by bridge piers. The Ambassador Bridge was opened in 1929 as the world's longest suspension bridge, a title lost with the opening of New York's George Washington Bridge in 1931.

Parts of this page were contributed by former GEO 333 student Mark Gordon.

This material has been compiled for educational use only, and may not be reproduced without permission.  One copy may be printed for personal use.  Please contact Randall Schaetzl (soils@msu.edu) for more information or permissions.