Greenspot Road Bridge Project and Street Improvements

Picturesque, grand, historic—City of Highland residents and visitors used many words to describe the steel truss bridge crossing over the Santa Ana River. Safe and practical were rarely among them. In fact, weight and width restrictions prevented simultaneous two-way traffic across the bridge.

Harris & Associates played a pivotal role on a project designed to create a much safer and more convenient alternative for drivers, pedestrians and bikers—a solution that enabled Highland to preserve its distinct landmark.

The project rehabilitated the steel bridge, now used solely by bicyclists and pedestrians, and constructed a new concrete bridge with four lanes for vehicle traffic—enhancing public safety and enabling future road expansion and utility crossings.

Core Elements

Harris & Associates provided construction management services for this $9.3 million project, which won two awards from the American Public Works Association: the IE award for Large Projects and the SoCal Chapter Award for Best Project in Transportation.

The team's work encompassed two bridges:

• A new 237-foot-long, 4-span, 98.5-foot-wide, concrete post tensioned cast-in-place box girder bridge with:
  • 5,500 feet of new asphalt roadway pavement approaches
  • A reinforced box culvert, RCP drainage system, fencing, gates and rock slope protection in the river
  • Block-outs for future utilities through the bridge cells
  • Architectural elements consistent with the city, including cobblestone textured walls, metal beam guard railing ROW fencings, signage striping and designer light poles with LED lighting, all located in environmentally sensitive areas
  • Pedestrian sidewalks and overlook areas
  • Spread footings due to the presence of large boulders, which created challenging excavation conditions
• Simultaneous retrofitting and restoration of the existing 100-year-old 250-foot-long steel truss bridge, which featured:
  • Replacement of some steel members (with temporary falsework supports while the work was done) and restoring other members to match the original bridge aesthetic
  • Repaving the bridge with an asphalt overlay
  • Replacing handrails and the entire wood deck to match the existing deck (made of timber and fastened with steel rods)
  • Cleaning and repainting of entire structure to match the steel handrails of the new concrete bridge

Beyond the Blueprints

Due to lead paint on the steel bridge, the retrofit, cleaning and repainting required full containment from start to finish, preventing the river and surrounding vegetation from exposure to lead contamination. Because of the wind loading, the containment work was performed in quadrants to prevent torque on the steel members. This also required survey monitoring of the bridge throughout the containment process.

There were also numerous environmental considerations to manage, including the protection of an endangered species habitat (the San Bernardino Kangaroo Rat), excavation in an active river and storm water pollution control. Harris secured permits from several environmental agencies and flood control agencies. A biologist provided training and oversaw the environmental portions of the project.