Flatiron’s Interstate 210 San Gabriel River Bridge Replacement Project delivered crucial structural improvements for California motorists and added 50 years to the lifespan of the existing structure.
In 2012, the Caltrans Office of Structure Maintenance and Investigations (OSMI) delivered the findings of their statewide bridge inspections, along with structure repair recommendations in the Structure Replacement and Improvement Needs (STRAIN) report. The STRAIN report, reinforced by an inspection of the San Gabriel River Bridge in 2016, recommended hinge and railing upgrades, otherwise, a bridge deck superstructure failure could possibly occur.
To preserve the structural integrity of the bridge and to prevent bridge deck failure due to settlement and nonexistence of elastomeric bearing pads in the hinges, the scope of work was determined: Demolition of hinge diaphragms at hinges 4 and 6 and reconstruction using rapid setting concrete; upgrade the existing bridge median barrier; upgrade the bridge railings; and removal and re-installation of the bridge electroliers (light fixtures).
Closing this portion of the freeway and redirecting all traffic to local roads would have resulted in unacceptable traffic delays, according to Caltrans, who cited an average of 217,000 vehicles a day on this portion of the I-210 according to a 2017 report. Another plan had to be devised.
Facing an onslaught of traffic that had nowhere else to go, Flatiron and Caltrans scheduled two 126-hour closures, first westbound, then eastbound. Flatiron then worked a little magic (in the mix) and successfully demolished and reconstructed the San Gabriel Bridge hinges two weeks ahead of schedule, thanks in part to the Construction Manager/General Contractor (CMGC) contract.
Innovative solutions were the order of the day for this project. The Flatiron crew had to divert the San Gabriel River to install temporary supports, lift the bridge with more than 80 hydraulic jacks, cut the bridge in half to complete the repairs, and protect 1,400 bats from potential construction impacts using sound blankets and walls.
To complete the work – full demo and reconstruction – within such a short window was a challenge and Flatiron rose to it.
The new concrete in the soffit and stem work required 3,000 psi in three hours. Flatiron rolled up their volumetric mixers with a specially formulated RSC mix and achieved 4,800 psi in the three-hour window and 10,000 psi in 24 hours. The new deck pour followed suit, and within the allotted timeframe, Flatiron successfully completed all of the work and reopened the 210 to traffic.
In recognition of this outstanding work on the San Gabriel River Bridge Hinge and Diaphragm Repairs Project, the International Partnering Institute (IPI) presented the team of Flatiron West, Caltrans District 7, and StreamLine Consulting with a Ruby Award. In the team picture above, Flatiron Area Operations Manager George Butorovich, center, holds Flatiron’s award, which was one of five the firm received at this year’s IPI Conference on May 16 & 17 in San Francisco.
Additional awards presented to Flatiron for the San Gabriel Project include the Caltrans Partnering Success in Motion Gold Award, the AGC of California Constructor’s Award in the Heavy Civil category, and the Construction Management Association of America Award.
Big thanks and a tip of the hard hat to Project Manager Jacob Cadmus for all of his great work on the project and help with this story.