Assigning Pier and Spandrel Labeling in ETABS


Wall piers are typically assigned in the model to the wall over height of floor (as in Figure d below).

Often, it is more appropriate to assign the pier to the height of wall adjacent to opening (Figure a or c), resulting in better calculations of shear/moments from the area object directly above/below the opening.
Unlike wall pier elements, a single wall spandrel element can include area
objects from two adjacent story levels. For Spandrel labeling you can follow the following figure

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Collapse of Tacoma Narrow Bridge

Watch the amazing “Gallopin’ Gertie” November 7, 1940 film clip.
1940 Tacoma Narrows Bridge.

Slender, elegant and graceful, the Tacoma Narrows Bridge stretched like a steel ribbon across Puget Sound in 1940. The third longest suspension span in the world opened on July 1st. Only four months later, the great span’s short life ended in disaster. “Galloping Gertie,” collapsed in a windstorm on November 7,1940.

The bridge became famous as “the most dramatic failure in bridge engineering history.” Now, it’s also “one of the world’s largest man-made reefs.” The sunken remains of Galloping Gertie were placed on the National Register of Historic Places in 1992 to protect her from salvagers.

A dramatic tale of failure and success
The story of the failure of the 1940 Narrows Bridge and the success of the Current Narrows Bridge is a great American saga. When Galloping Gertie splashed into Puget Sound, it created ripple effects across the nation and around the world. The event changed forever how engineers design suspension bridges. Gertie’s failure led to the safer suspension spans we use today.