Decongesting Diamond Bar

$78 Million Project to Elevate and Link HOV Lanes

About 353,000 motorists slowly squeeze through the interchange of the Pomona and Orange freeways every day. New flyover connectors will allow motorists traveling between the 57 and 60 freeways to change routes without leaving the HOV lane, which should reduce weaving and improve safety.

By Greg Aragon and Paul Napolitano

The dreaded 57/60 interchange in Diamond Bar is getting $78 million worth of improvements designed to expedite traffic flow through the busiest freeway junction in Los Angeles County.

"It's always backed up through here," said Terri Cornett, 46, whose daily commute from her home in Covina to her office in northern Orange County takes her through the interchange. "The traffic just crawls almost any time of the day."
She said her 22-mi. trip takes "about an hour each way."

The California Department of Transportation has not determined how many minutes the new interchange will save for motorists, but Judy Gish, an information officer for Caltrans District 8, said "benefits of the improvements will be major."

When the project is complete in summer 2006, Cornett and other motorists -many commuting from their homes in western San Bernardino County to jobs in northern Orange County-would be able to make faster and safer transitions between the HOV lanes of State Route 60 (Pomona Freeway) and State Route 57 (Orange Freeway), Gish said.

In a nutshell
Begun in early February, the project's largest component is construction of a new bridge to link the HOV lanes between the 57 and 60 in Diamond Bar and the city of Industry. The project also includes realigning the Grand Avenue on-ramp to westbound 60, constructing a new collector road adjacent to westbound 60 and adding an auxiliary lane to the Grand Avenue off-ramp from eastbound 60.

The 70-mi.-long Pomona Freeway stretches from downtown Los Angeles on the west, to the city of Beaumont in Riverside County at its eastern end. The Orange Freeway is 20 mi. long. It runs from San Dimas, a city of about 36,000 in eastern Los Angeles County, to Santa Ana, a city of 360,000 in the geographic center of Orange County.

More people, more cars
The project is necessary because of meteoric growth in western San Bernardino County cities such as Alta Loma, Chino Hills, Fontana and Rancho Cucamonga. Ten years ago, 166,000 motorists a day passed through the interchange. Today, 353,000 motorists use the interchange. The freeways were first built through Diamond Bar in 1959.

The current freeway configuration requires motorists to make quick lane changes, crossing three lanes to access connecting freeways and HOV lanes. The new direct connector will allow HOV traffic traveling between the 57 and 60 to change routes without leaving the HOV lane, which will reduce weaving and improve safety.

Led by Rancho Cordova-based general contractor C.C. Myers Inc., the project is currently in the bridge-column foundation stage.

Bob Schneider, Southern California operations manager for C.C. Myers, said that because the soil beneath the bridge is full of soft clay, Caltrans designed the columns to be placed in 130-ft.-deep, 11-ft.-diameter CIDH.

"We're building these big heavy structures, and the underlying geography of this area is a material with extreme settlement issues," Schneider added. "That's why these shafts are so big; to carry these bridge columns."

He said that on a typical freeway job (without the presence of clay) standard concrete piles driven to a depth of 10 or 12 ft. would be used.

When complete, the new HOV connector will feature 28 columns standing between 17- and 42-ft. high. Each column hole will use about 300 to 400 cu. yds. of concrete (supplied by Holiday Ready Mix of Upland and pumped by C.C. Myers) and require rebar cages (provided by United Steel Placers of Rancho Cucamonga) weighing more than 200,000 lbs.

To lift and set the cages in place, C.C. Myers is using two massive Bragg cranes—a 225-ton crawler and a whopping 450-ton crawler, one of the largest cranes in California, Schneider said.

The precision involved in these picks is critical
"If anything goes wrong, you could cause major impact on traffic because once you pick it up, you can't lay it back down; you don't get two chances at it," Schneider added. "As a precaution, on the first [rebar setting], we closed the freeways and set it at midnight, and made sure our planned methods worked correctly."

Irvine-based Ortiz Enterprises is the subcontractor in charge of earthwork and on-site grading, as well as the building of all retaining and mechanically stabilized embankment walls.

Patrick Ortiz, the company's CEO, said that staging material and working around heavy traffic are the biggest obstacles he has faced so far. "There's a lot of congestion on this interchange and it definitely needs improving," said Ortiz, who has more than 30 years of experience building, upgrading and elevating freeway interchanges in Southern California. "C.C. Myers has to build a big flyover bridge in the middle of the freeway, but they can't do that until we get the walls built and move the traffic to the outside."

By the end of the year, Schneider said that his crew would be "in the home stretch," with the bridge about 50-percent done and the overall project about 33-percent complete.

The project, officially known as Orange Freeway/Pomona Freeway High Occupancy Vehicle Lane Direct Connector and Collector Road Project, was financed by the State Transportation Improvement Program.