Local media were provided a nice tour this morning of the work being done on the “Iconic Bridge” being built over the eastbound 210 freeway for the Gold Line Foothill Extension in Arcadia. The Measure R-funded project will extend the existing Gold Line from its terminus at Sierra Madre Villa in Pasadena for 11.5 miles to the Azusa/Glendora border, a trip that will only take about 20 minutes.
The 584-foot linear bridge will carry the tracks from the median of the 210 to the south side of the freeway. The old single-track railroad bridge — at that point, long out of use — was torn down in 1997 because it needed serious seismic upgrades and was too narrow to accommodate the tracks in both directions needed for light rail. The new bridge almost sits atop the footprint of the old bridge.
Skanska, the contractor, began serious work on the $18.6-million bridge over the summer and is scheduled to be complete in July 2012. The steel frame for two of the three bridge columns (and their associated deep foundations) are in the ground and the third is being installed this week. The two deep completed foundations are 110-feet-deep and 11-feet in diameter — motorists on the 210 can only see the 16 feet steel skeletons that are above ground. The accompanying photos show some of the work done to date.
A few other interesting factoids about the project:
•The three deep foundations have nearly 11 miles of rebar, as well as more than 1,300 cubic yards of concrete from Irwindale (local materials!). They also have a relatively new technology — never used before by Metro — that that in the future will allow Metro to check the structural integrity of the concrete after earthquakes by measuring electrical pulses traveling along wires inside each abutment.
•In December, work crews will begin installing the falsework allowing them to build the bridge itself. The temporary support for the bridge must span the width of the freeway for the entire stretch across the freeway, which will create a tunnel of sorts for the eastbound 210 while work is being done.