Current Topics

Students Fill in Missing Piece of Bay Bridge East Span

January 17, 2013

“It’s missing a piece.”

“The piece fell down.”

Kindergartners in Autumn Ayllon’s class at Shore Acres Elementary School in Bay Point immediately saw what was wrong in a picture of the San Francisco-Oakland Bay Bridge depicting the deck section on the East Span that fell during the Loma Prieta earthquake in 1989. The youngsters were looking in 3-D through old-fashioned viewfinders distributed during a presentation by the East Span outreach team.

From there, it was only a viewfinder-click away to introduce construction of the new, seismically safe East Span, scheduled to open during the 2013 Labor Day weekend. After viewing pictures of the new skyway, the Left Coast Lifter (a special crane built to lift the 700-ton deck segments into place), the 15-1/2 foot bike/pedestrian path from Oakland to Yerba Buena Island and the new self-anchored suspension system, or SAS, the kindergartners were ready to tackle a special Activity Booklet on bridge facts.

The fifth-grade class of Denise Nunally got to hear even more bridge facts during the viewfinder presentation. They learned that the bridge is asymmetrical, and that each wire in the main cable of the SAS is strong enough to hold up a military-grade tank (137 bundles of 127 wires make up the main cable). And they got to actually tackle an engineering task – putting together a model of the East Span that was created by the Lawrence Hall of Science. The model kit includes two road pieces, a base, the tower, three crossbeams, the main cable with magnets for counterweights, and falsework. It was quite a challenge for the fifth-graders to get their bridge models ready for load transfer, when the falsework was removed and the bridge deck was held up by the cable alone.

“I’m going to be an engineer,” one student proclaimed after his group had achieved the load transfer.

Outreach to students from kindergarten through college on the building of the new East Span is presented by the San Francisco-Oakland Bay Bridge Seismic Safety Projects, comprised of Caltrans, the Bay Area Toll Authority and the California Transportation Commission. For a detailed description of the load transfer, visit www.mtc.ca.gov/news/current_topics/11-12/sfobb.htm.

—Georgia Lambert