This Project Is Up in the Air

Freeway-to-Freeway Flyovers for Riverside Interchange

A $317 million makeover of 60/91/215 freeway interchange near downtown Riverside began in March. Improvements to the often-congested lanes will include two freeway-to-freeway flyovers, widening the freeway from six to eight lanes, replacing four bridges, building new bridges and widening bridges. Washington Group/Obayashi Corp., a Joint Venture, is scheduled to finish the job in early 2007.

By Greg Aragon

The largest transportation improvement project in Riverside County will include some of the deepest bridge foundations ever drilled for a California freeway.

The $317 million makeover of the 60/91/215 freeway interchange near downtown Riverside will include adding two freeway-to-freeway flyovers, widening the freeway from six to eight lanes, replacing four bridges and building seven new ones and widening nine more. About 150,000 vehicles pass through the junction every day.

The massive project got under way in March and is scheduled for completion in 2007.

The project also involves designing and building connector sections of State Route 60 (Pomona Freeway) and State Route 91 (Riverside Freeway); constructing about 80 retaining and sound walls and 2 mi. of draining pipe; and the creation of a truck-climbing lane in the Box Springs Grade area of the 215/60 interchange in Moreno Valley.

Led by Washington Group/Obayashi Corp., a Joint Venture, the 7.8-mi.-long project has a construction cost of $186 million and is scheduled to last approximately 34 months.

Michael Aparicio, project manager with Washington Group/Obayashi, said erecting 49 columns for the two flyover bridges is his biggest immediate concern. The 100-ft.-high columns will require the drilling of 15-ft. diameter by 130-ft.-deep holes and consume about 500 to 600 cu. yds. of concrete per hole.

"The massive foundations for those bridges are some of the biggest and deepest cast-in, drilled-holed foundations ever built-anywhere," Aparicio added. "Opening up a hole of that size in the middle of a [busy] freeway without any room to stage material for the huge rebar that goes in these holes is like trying to build a shaft on a postage stamp."

Washington Group/Obayashi will self-perform the concrete; Robertson Ready Mix of Corona will supply it.

"We'll have to plan how we're going to excavate the shafts, where the dirt is going to go and the amount of concrete we can pump into a hole in a single shift," Aparicio said.

"The project is being built by "design-sequencing," a method in which Caltrans designs about 33-percent of the work before releasing it to the contractor.

The method will save at least a year off a more traditional schedule of starting construction after the entire project's design is completed, said Mark Lancaster, Caltrans project director and acting deputy director for design. He added that freeway improvements are expected to save commuters about 20 minutes in the morning and 20 minutes at night.

"[The interchange] often runs at congested levels due to lack of weaving distance between freeway direct connectors," Lancaster said. "The traffic congestion will be greatly alleviated due to the fact that we have direct connectors from one freeway to the other.

"Motorists will have plenty of distance to merge into the main line before people have to get off at the next interchange."

Before bridge building can begin, however, a main electrical line that runs over Interstate 215 in downtown Riverside had to be relocated away from the new freeway connectors.

"The electrical poles are within a railroad corridor, so we had to get the cabling out of the corridor and put them under local streets and behind businesses in parking lots," Lancaster said.

The project is currently in the first of three phases. The interchange will be about 33-percent complete by January at which time Caltrans will release its second sequence.