More than $430,000 has been spent on Orange County’s Eastern tollway to repair bumps and uneven pavement in 16 areas that apparently were caused by earth movement under the roadbed, government records show.
Since the turnpike designated State Route 241 opened four years ago, the Transportation Corridor Agencies and Caltrans have been dealing with flaws in the highway, particularly the Windy Ridge area, a steep hilly pass south of the Riverside Freeway where 14 million cubic yards of soil were removed to build the road.
Tollway officials describe the bumps as a minor problem not uncommon after substantial earth is shifted in extreme terrain. To cut a path for the tollway, 67 million cubic yards of soil -- equal to a quarter of that excavated for the Panama Canal -- had to be moved. TCA officials say the bumps affect less than 1% of the 24-mile road.
“This is a natural phenomena that has appeared over time,” said James Brown, director of engineering and environmental planning for the TCA. “If it were going to get bad, we would have seen the worst of it by now. It’s just a matter of time before the rebound and expansion of the soil will end.”
Caltrans estimates it has spent about $196,500 on repairs to the road so far, while the TCA has paid about $45,000. The road’s builder, Silverado Constructors, spent about $192,000, according to records for the Eastern corridor repairs. The work included grinding down the bumps and repaving the spot.
TCA officials say the bumps, which have appeared since 1999, do not threaten highway safety and are unlikely to trigger major failures of the pavement. No claims for damages have been filed by motorists, they said.
But TCA records also show that the road’s engineers do not know whether the soil movement will become an increasingly costly long-term problem for the agency and Caltrans, which took over maintenance of the Eastern tollway in early 2000.
“There is no way to know if the bumps have already stabilized or if they will continue into the future,” Doug Tugwell, a project manager with Raytheon Engineers and Constructors, wrote in a January 2001 letter to the TCA. “And if they continue to increase in the future, how long will it be before they stabilize, if ever? ... It is even possible this will be a continuing maintenance problem.”
TCA records further indicate that Caltrans officials have suspected that inadequate geological investigation preceded the tollway construction. They also contended that there were design and construction deficiencies caused by Silverado.
Caltrans officials declined to comment on the pavement problems, saying it was premature to draw conclusions. The state agency is preparing a report about the situation that is scheduled to be released soon.
A geological study paid for by Silverado Constructors concluded that the uneven pavement could have been caused by three factors: soil rebounding after a cut 300 feet deep, expansion and shrinkage of the exposed soils in rainy and dry seasons, and expansive soils in an inactive fault zone near the worst area of previous earth movement.
Masanobu Shinozuka, chairman of UC Irvine’s department of civil and environmental engineering, said earth movement under a freeway is uncommon.
“You are dealing with lots of uncertainty with huge projects,” he said. “There have been tremendous gains in our understanding about earth movement and settlement, but we do not have perfect knowledge.”
The Eastern tollway, which runs from the Laguna Freeway to the Riverside Freeway, is part of a 51-mile network of turnpikes operated by the Transportation Corridor Agencies, a government entity based in Irvine. Other parts include the Foothill tollway, a short section of the Laguna Freeway, and the San Joaquin Hills tollway.
The Eastern and five miles of the Foothill together cost about $1.5 billion to build. A 17-mile stretch of the Eastern opened in October 1998; the rest went into service in February 1999.
Brown said the patched sections of the road will be resurfaced again when earth movement stabilizes. But he downplayed the expense, saying “Caltrans spends more on sprinklers and pulling weeds.”
TCA records show at least 16 parts of the tollway where the bumps have been discovered, including Windy Ridge, Loma Ridge, Handy Creek Road and Chapman Avenue. All the areas are associated with large-scale earthwork, Brown said.
Much of the dirt was cut out of Windy Ridge, a high point on the steep turnpike that slices through foothills of the Santa Ana Mountains linking Riverside and Orange counties. The area measured a quarter-mile wide at the top and extended into a deep canyon.
“The vertical removal plunges to 310 feet from the crest. The highest vertical fill, covering one of the canyons below Windy Ridge, rises by 425 feet,” according to information from Sukut Construction Co., the Southern California earth-moving company that did the job. “Windy Ridge is the high point of the project in more ways than one. It also represents the deepest cut and the major source of earth transfer.”
TCA records show that as of May 2001, Caltrans was contending that Silverado was responsible for design and construction deficiencies, and that Caltrans was investigating the uneven pavement but had not released any findings at the time.
The records note that during construction, concerns were raised about the adequacy of the geological investigation, yet construction proceeded. Records noted that samples of certain graded areas were not taken.
According to TCA documents, Caltrans officials believed at the time that Silverado was responsible for coming up with a long-term solution and reimbursing any costs incurred by Caltrans to fix the pavement.
TCA officials contend in the documents that the road was built to Caltrans standards and with plans and specifications approved by the agency. TCA officials noted that the issue has been discussed for months and that Caltrans has yet to provide any evidence of deficiencies caused by Silverado.