Gold Line Bridge

The Gold Line Bridge is the first completed element of Foothill Gold Line Construction Authority’s Gold Line Light Rail Program Phase 2A, which comprised a 11.5-mile extension of the Los Angeles County Metropolitan Transportation Authority’s A Line (formerly Gold Line) from Pasadena to Azusa. Spanning the eastbound I-210 freeway, the 584-foot bridge provides a connection for the dual-track light rail system between the existing Sierra Madre Villa Station in Pasadena and the new Arcadia Station in Arcadia.

Award-winning public artist Andrew Leicester developed the design concept inspired by the San Gabriel Valley’s indigenous people, agricultural history, and wildlife. The bridge structure features signature support columns capped with 25-foot-tall precast basket elements. It also includes a ribbed exterior girder system that mirrors the underbelly of the western diamondback rattlesnake.

The Metro Gold Line Foothill Extension Construction Authority, with the support of Hill, served as construction manager for the project. The construction management team prioritized engagement and frequent communication through weekly design, construction progress, and quality review meetings. Frequent informal partnering and issue resolution meetings also helped facilitate teamwork and address issues quickly and effectively. The project was supported by a dispute resolution board, which was retired midway through the project by mutual agreement.

The contract required the design-builder to submit a quality assurance/quality control (QA/QC) plan for the design and construction phases of the project. The contract also required staff independent of the production organization to oversee the contractor’s quality management team, as well as the utilization of third-party inspection and testing agencies. This independent organization worked closely with the QA/QC team to deliver a fully documented project in compliance with all contract terms. This success was possible because of weekly meetings, during which the design-builder’s quality management team, the Construction Authority, and Caltrans reviewed requests for information, drawing revisions, and quality reports and resolved non-compliance and deficiency items. A total of 98 requests for information and 14 non-conformance reports were issued on the project.

The bridge’s project conditions were well-defined, and unforeseen conditions amounted to less than 2% of the cost. Prior to procurement, the Construction Authority embarked on an extensive earthquake fault study to minimize bid risk and manage project costs. During construction, the Construction Authority added several owner enhancements to the scope of work, amounting to approximately 5% of the total cost. These enhancements focused on aesthetic and architectural elements, including work originally scheduled to be completed by the follow-on contractor who built the rail infrastructure on the bridge. At the completion of the project, both the Construction Authority and the design-builder were able to stay within their respective budgets.

During construction, the design-builder faced many challenges working within a constrained site over a heavily used freeway. Hill helped to manage these challenges by planning and coordinating with Caltrans, the City of Arcadia, residents, and the traveling public. Approximately 65 full freeway night-time closures were needed to erect and remove falsework, place concrete, and restore the site. The design-builder constructed the soffit and stems of the superstructure during a single 20-hour concrete pour requiring 3 simultaneous operations to place 2,200 yards of high-strength concrete. The team performed more than 100 nights of work between midnight and 5:00 a.m.

The CMAA Southern California Chapter recognized Hill with a Project Achievement Award in the Transportation Projects Between $11-$50 Million category for our work on the Gold Line Bridge.

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