SAN DIEGO, California – SANDAG’s Mid-Coast Trolley project recently reached another impressive milestone with the final girder required to form an important track flyover being set in place. In total, 48 pre-cast girders make up the flyover, an elevated portion of the Trolley guideway that goes up and over pre-existing railroad tracks that run along Rose Canyon.
As one of the lead bridge engineers for the project, Kleinfelder completed the structural design for the Rose Canyon flyover. With sensitive plant and animal species and an active fault line running through Rose Canyon, Kleinfelder’s design accounted for environmental impacts, hydraulic and scour impacts around the bridge foundations, seismic hazards, and compliance with all regulatory freeboard requirements. The most significant design challenge was the Rose Canyon Fault Zone within the bridge alignment, affecting two spans and their supporting foundations. The estimated fault displacement is approximately 5 feet in the longitudinal direction of the bridge and about 1.2 feet vertically. The bridge was designed and detailed to accommodate potential seismic displacements. Kleinfelder has continued to provide leadership throughout construction of the Rose Canyon track flyover, helping to advance the project to timely completion.
“It’s exciting to see the project reach this milestone which marks the end of construction of the main structural components over the existing active railroad tracks. Beyond this milestone, safety at the construction site is enhanced by less heavy equipment, resulting in lower construction risk. In addition, this is one of the major bridges in the Mid-Coast project and the bridge now looks like a bridge,” said Kleinfelder’s Project Manager Jim Frost.
In addition to working on the Rose Canyon flyover, Kleinfelder completed the structural design for eight other bridges and the nine transit stations along the 11-mile trolley corridor. Kleinfelder also supported the project by providing preliminary geotechnical and hazardous material analytical services in support of the preliminary 30% design and Supplemental Environmental Impact Report/Supplemental Environmental Impact Statement studies. An extensive geotechnical exploration program, which included over 290 borings and a fault hazard study, was also conducted.
With service anticipated to begin in late 2021, the Mid-Coast Trolley extension will expand transportation capacity in the Mid-Coast Corridor to accommodate existing and future travel demand and will provide an alternative to congested freeways and roadways for travelers.
Founded in 1961, Kleinfelder is a leading engineering, construction management, design and environmental professional services firm. Kleinfelder operates from over 60 office locations in the United States, Canada, and Australia. The company is headquartered in San Diego, California.