Tacoma Suspension Bridge

On November 7th, 1940, the Tacoma Bridge collapsed into the Tacoma Narrows straight in Washington State. The bridge connected the town of Tacoma and the Kitsap Peninsula, and was one of the first major suspension bridges in the western United States. Unlike other suspension bridges constructed around this time, the Tacoma Bridge failed to withstand wind speeds over 40 miles per hour, due to unequal stress on parts of the bridge. The construction of a suspension bridge must include geometric shapes and and have some sort of symmetry to stay up. These shapes can include triangles (from the anchors of the bridge the towers), rectangles (the towers), squares, and other shapes, depending on the bridge. Bridges also have right angle measures, straight angle measures, line segments, rays, and parallel and perpendicular lines. Also, a suspension bridge can only stay up if it can hold its own weight (dead load), and the traffic crossing it (live load). The loads create 2 forces called compression and tension. The compression pushes down on the suspension bridges deck, and the bridge’s cables move the compression to the towers. Then, the compression dissolves in the ground, where the …show more content…
Also, the Mackinac Bridge has stiffer trusses, allowing to reduce wind resistance and to support the weight of the bridge’s deck. The deck of the Mackinac Bridge is slightly more curved and provides lift in a cross wind (allowing more vertical airflow), making the roadway stable up to wind speeds of 150 miles per hour. At the time the Tacoma Bridge was built, little was known about aerodynamics and wind dynamics, which may have lead to the falling of the bridge. The Tacoma Bridge was known to have some aerodynamic instability after construction, but the architects failed to notice this during the bridge’s