Retrofitting San Diego’s “People’s Bridge” to be Seismically Safe
Shrouded by eucalyptus in Maple Canyon is one of San Diego’s most impressive bridges. This #seismicsaturday we feature the 1st Avenue Bridge. The 463-foot bridge was built in 1931, and is nicknamed “The People’s Bridge” as it was funded by San Diego’s first public infrastructure tax. The bridge was actually assembled first in Ohio, before…
How do you use bedrock and octagons to build a strong bridge?
This #seismicsaturday, we feature the Black Canyon Arch Bridge, built in 1913 Northeast of Ramona in Eastern SD County. An arch relies on its foundations to push both upward and inward. The shallower the arch, the more sideways force is needed (fig. 2). For the Black Canyon Bridge, the arch is built directly into the bedrock…
Richmond San-Rafael Retrofit: “The most complex single retrofit program ever attempted by Caltrans”
“Mr./Ms. Engineer, your mission, should you choose to accept it, is to retrofit the Richmond-San Rafael ‘roller coaster’ Bridge. The bridge, measuring 22,000 ft, has 4 different steel structural systems along its length. Most spectacular are the two 1070 ft spans over active shipping channels – each made by two 535 ft-long cantilever arms that…
The Carbon Fiber Cable-Stayed Bridge that Could Have Been…
The bridge that could have been… For #seisimicsaturday we feature the proposed (but never built) carbon fiber/fiberglass Gilman Street Bridge. With UC San Diego expanding east in the 90s, there was need for a bridge across highway 5 at Gilman Drive. Several UCSD professors, among them prof. Van Den Einde and Frieder Seible, designed an innovative cable-stayed…
Can You Make a Bridge Out of Telephone Poles?
This #seismicsaturday we feature a 150ft long bridge over the Ausable River in the Adirondacks Mountains of New York. The bridge foundation is built from stones piled on top of one another, with cement in between (pic 2). The foundation is built in a hydrodynamic shape with a pointed front, making it look similar to a boat…
Sweetwater Bridge: a Beautiful and Historic Steel Bridge in Eastern San Diego
Figure 1: The Sweetwater Steel Truss Bridge in Eastern SD County Nestled in the Sweetwater River Valley along Highway 94 is the 1929 Sweetwater River Bridge. For #seismicsaturday , we feature this wonderful example of an old steel truss bridge. The design of the bridge is a Pratt Truss (fig. 2). This means that the diagonal members…
Rebuilding the Historic Georgia Street Bridge
Would you fight CalTrans to save historic arches? This #seismicsaturday we feature the Georgia St Bridge in the Hillcrest neighborhood of San Diego. In the early 1900s, city planners in a rapidly-expanding San Diego wanted a streetcar line down University Ave to connect the new suburb of North Park with the city. The biggest roadblock…
Quince Street Bridge: The Oldest Functioning Bridge in San Diego
What is the oldest functioning bridge in San Diego? This #seismicsaturday we feature the Quince Street Bridge. The Quince St. Bridge was built in 1905 to connect residents of the then fast-growing Bankers Hill neighborhood to the trolley line in 4th avenue. The bridge is 263 ft long and 60 ft tall. It cost just…
UC Santa Cruz Pedestrian Bridge: A Bridge Strong in 3 Directions
How do you build a 200 ft long wooden bridge over a ravine just 10 miles from the San Andreas fault? This #seismicsaturday we feature a beautiful glu-laminated wooden pedestrian bridge at UC Santa Cruz. The bridge deck is supported by three thick glu-laminated beams (fig. 2). These “glu-lam” beams are made by gluing many…
Smolen-Gulf Bridge: 613 ft-long and Made of Wood!
What did bridges look like before steel and reinforced concrete? This #seismicsatueday we feature the Smolen-Gulf Bridge in Ashtabula, Ohio. Measuring 613 ft, the bridge is the longest wooden truss covered bridge in the US. Popular in the 1800s, a “covered bridge” is a wooden truss bridge with a truss roof. The roof protects the bridge deck…
Susquehanna River Bridge: A Wonderfully Redundant and Riveted Historic Railroad Bridge
This #seismicsaturday is riveting! We feature a 1904 railroad bridge across the Susquehanna River near Cooperstown, NY, which your Seismic Saturday correspondent spotted while canoeing. In late 19th century and the early 20th century, when Cooperstown and surrounding areas were manufacturing hubs, the bridge was part of a bustling train route that brought raw goods…
Saul Chaplin 