The Foothill Gold Line light rail project from the Southern California cities of Pasadena to Azusa is only weeks away from welcoming passengers on March 5. And as crews conduct last minute tests to trains, tracks and control and communication systems, the Foothill Gold Line Construction Authority, the entity which oversaw construction of the nearly $1 billion project, can look back on a successful and challenging multi-faceted job.

One of the most fascinating challenges of the project was the construction of the 584‐ft-long Gold Line Bridge, which stretches diagonally across the five‐lane Eastbound I‐210 Freeway in the city of Arcadia, about 15 miles northeast of Downtown Los Angeles.

"Constructing this bridge was challenging because the bridge was built over a large active freeway and a seismic fault," says Chris Burner, chief project officer for The Authority. "Although conventional wisdom calls for avoiding any such surface fault rupture zones, this was not an option for the project alignment. A complex fault study was performed prior to contract award in lieu of the original plan of assigning that task to the design-build contractor. This proactive approach resulted in schedule savings of approximately six months."

Burner says building the bridge over a fault line created many design complexities which were successfully overcome with planning and an innovative use of “smart foundations” which integrate time-domain reflectometry (TDR) technology into the pile foundations.

"During a seismic event, the TDR technology will use fiber optic cables to predict the location of potential underground damage," he says. "This was the first use of this approach in California."

Construction of the 11.5-mi-long, six-station project was managed by The Foothill Gold Line Construction Authority. The project reached substantial completion last September and was turned over to Los Angeles Metro to manage.

Last month the Gold Line was awarded a Project Achievement Award for design-build projects worth more than $100 million by the Construction Management Association of America’s (CMAA) Southern California Chapter. The award follows the on-time, on-budget completion of the project and recognizes the success of the design-build procurement process.

Hill International, the agency’s program manager, submitted the project for award. The award will be presented to the Construction Authority in April at CMAA’s 24th annual awards gala in downtown Los Angeles.

The project, which broke ground June 26, 2010, has been led by three design-build teams. The first contract was awarded in June 2010 to Skanska USA to design and build the iconic, basket-shaped Gold Line Bridge in the city of Arcadia. Construction on the 584-linear-ft-long bridge began in July 2011 and was completed in December 2012.

In July 2011, the second contract was awarded to Foothill Transit Constructors - A Kiewit Parsons Joint Venture to design and build the Pasadena to Azusa "alignment," which included the stations, track, crossings, bridges, etc. This $515 million design-build reached substantial completion on September 23, 2015.

The last contract was awarded in February 2013 to Webcor Builders for the intermodal parking facilities and enhancements design-build project. All three design-build teams completed their work on time and on budget.

To construct the new light rail system, construction crews worked more than 2.4 million hours to build six new stations, a 24-acre Operations Campus, 24 bridge structures, and 14 at-grade crossings. They relocated four miles of freight track, welded 56 miles of steel rail, used 75,000 concrete ties and 300,000 e-clips, and erected 620 OCS (overhead catenary system) poles.

Currently , The Construction Authority is undergoing advanced conceptual engineering for the Foothill Gold Line's next segment from Glendora to Montclair. The agency is on schedule to break ground on the first design-build project in 2017; it will take five to six years to complete the 12.3-mile, six station light rail extension. This schedule is dependent on securing construction funding, which is anticipated to come from a tax measure being proposed for the November 2016 ballot.