The lines of this highway bridge near the Salton Sea are nothing fancy.
The structure’s lineage, however, is pure high-tech.
In a unique transfer of military technology to the civil infrastructure, the bridge is built with lightweight, advanced materials commonly used in aerospace.
Steel rebar is kept to a minimum.
Concrete is used, though the forms it is poured around stay in place once the work is done.
The companies that built the bridge components have names associated with defense contracting: North Carolina-based Martin Marietta Composites and Minnesota-based Alliant TechSystems, Inc.
The bridge carries State Route 86, a desert highway, over the Kings Stormwater Channel. It’s a project of the UCSD Jacobs School of Engineering, Caltrans and the Defense Advanced Research Projects Agency, or DARPA.
It’s actually a test of multiple technologies.
Bridge girders and deck supports are structural shells , tubes made of lightweight, carbon fiber-reinforced polymers, which are filled with concrete at the construction site.
The project also includes similar material reinforced with glass fibers.
School representatives noted the composites do not corrode like steel rebar, are up to five times lighter than steel and can be installed without heavy construction equipment.
Using carbon shells is “revolutionary,” said Gil Hegemier, who leads the UCSD/DARPA research program, looking to a day when such forms might compete in the multibillion-dollar construction market.
Frieder Seible, structural engineering department chair, designed the project.
Caltrans will now monitor how the bridge holds up to the elements, traffic, seismic activity and age.
The way Caltrans will watch the bridge makes it a trendsetter in another way.
The bridge contains a variety of sensors, letting Caltrans and university officials watch it from afar.
Watching infrastructure from a distance is a key project for the California Institute for Telecommunications and Information Technology, UCSD’s recently announced joint project with UC Irvine.
The institute will build a prototype of a new environmental monitoring infrastructure that can collect data from a wide variety of sensing devices, communicate it to a central archive, then analyze it in a control room similar to those seen in space launches.
Eventually the state may use this remote sensing concept for more than roads. It could use it to monitor things like water pollution or the depth of the Sierra snowpack , which provides both water and hydroelectric power.
