CALTRANS HOPING WORK WILL TAME ROUTE 52 ROLLER COASTER
Built on landfill, shifts below asphalt create dips, dives in road
In Southern California, where the car has long been king, completion of a new section of freeway can be cause for celebration.
So it was on two summer days in 1987 and 1988, when off icials held four-hour parties in the center of soon-to-open stretches of state Route 52 in Kearny Mesa. There were refreshments, live music, dancing, military exhibits, parades — mini-carnivals, minus the thrill rides.
Those would come later. These new patches of pavement, which stretched about 5 miles east from Interstate 805 to Santo Road and cost about $33 million, were built in part over portions of the Miramar Landf ill that had closed 14 years earlier.
Before too long, the roadway started sinking in various places, creating a roller coaster ride of dips and undulations that made driving it an adventure — fun to small kids bouncing up and down in the backseat, aggravating to drivers worried about shock absorbers and front-end alignments.
Maintenance crews went out and put down an overlay of asphalt, smoothing the roadway. Then parts of it sank as the ground underneath shifted again. That meant more asphalt. This has gone on every few years, costing taxpayers millions of dollars in repairs.
Now Caltrans is trying a different approach.
Crews are drilling thousands of holes in the pavement, through all those layers of asphalt, and injecting columns of grout — a mixture of sand, water and cement — that they hope will compact the underlying soil, fill in cavities and entomb some of the decomposing and ever-shifting trash.
They experimented with that approach on a small section of the freeway in 2016. “The results look promising,” said Shawn Rizzutto, the transportation agency’s acting division chief for maintenance in San Diego and Imperial counties. “It firmed up the subgrade and limited the instability.”
Since late August, they’ve been working in the area between the 805 and state Route 163, sometimes seven nights a week, f lattening the roadway and streng thening nearby culverts. The $16.5 million project is scheduled to be finished in November, officials said.
Construction has meant lane closures and freeway ramp shutdowns, inconveniences that annoy motorists and leave them muttering unkind things about “your tax dollars at work.”
But this fix, if it works, could also make a significant difference to those using one of the county’s busiest east-west corridors. Caltrans records from 2017 show that, during the 24 hours of an average weekday, 112,000 vehicles travel in each direction on Route 52 where it meets Convoy Street.
That’s a lot of roller coaster rides.
‘Sweetheart of a freeway’
Rizzutto said he can’t speak for the Caltrans personnel who in the late 1980s designed and constructed the part of Route 52 that passes over the old dump.
He suspects they “did not anticipate the severity” of the roadway sinking caused by “the biodegradation, creep and consolidation” of the landfill materials, or the frequency of the asphalt overlays that would be required over the years to f latten it out.
Newspaper coverage of the freeway-opening celebration in 1987 suggests he is right. Officials back then said one reason they were having a party is because construction had gone so well.
“It’s been a sweetheart of a freeway to build,” one official told a reporter, noting the wide-open spaces it went through — no structures or trees to work around. That phase of the project, from the 805 to Convoy, was finished in about 18 months. It took another year to continue the highway to Santo Road.
These were the first new sections of the 52 to be built since the early 1970s, when it was known as the Soledad Freeway. Its original stretch connected Interstate 5 (where it meets Ardath Road) and Interstate 805, passing through San Clemente Canyon.
Subsequent extensions have taken the 52 through Tierrasanta and into Santee, where it links up with state Route 67. Those extensions have had their issues, too — funding, endangered species, rights-of-way — but a regularly sinking roadway hasn’t been among them.
The old dump in Kearny Mesa was known as the South Miramar Landfill. It started in 1959, after city officials leased 192 acres from the military on the southern end of what is now Marine Corps Air Station Miramar, according to a history on the city’s website.
Used mostly for residential trash, the landfill was closed in 1973 and the city moved to new locations nearby, first north and then west, where the operations continue today.
The undulations on Route 52 became common enough over the years for Caltrans to install yellow “DIP” warning signs next to the freeway. Sometimes the conditions prompted motorists to complain to the transportation agency or the news media.
“The dip is so bad that it actually jars your suspension,” Ron Yager, a Santee resident, told the UnionTribune in 2007, when the newspaper was running a regular “Just Fix It” feature. “You can hear it go ‘clunk’ as you hit it.”
He developed a strategy: staying in the fast lane. The other lanes, he said, had sudden drops that “could easily knock your front end out of alignment, or worse.”
Deadly concerns
A letter published by the Union-Tribune last year sounded a more ominous tone. “Cars encounter multiple dips that send them simultaneously down and side-to-side,” Don Johansson of Cardiff wrote. “Caltrans needs to stabilize the situation — a permanent fix would require moving the road — before people are killed.”
There have been deaths, primarily caused by excessive speed. In one of the accidents, in 2012, two East County teens were killed when the driver of a car racing another at more than 100 mph lost control near Convoy Street and crashed.
An attorney representing one of the victim’s parents sued the driver and also filed a liability claim against Caltrans — a possible precursor to a suit — alleging that the condition of the roadway contributed to the crash.
The claim was denied, and the attorney, Fred Cohen, said he dropped that part of the case after his traffic experts concluded that the freeway is reasonably safe as long as motorists obey the speed limit.
Caltrans doesn’t need driver complaints or threatened lawsuits to know the freeway has problems. “It’s something we monitor quite closely,” said Rizzutto, who’s been with the agency for almost 30 years.
Maintenance crews check when they’re working in the area, he said, and an automated system records the condition of the roadway when a specialized vehicle is driven over it. That information helps the agency prioritize repair projects.
The current work involves “compaction grouting,” a process that has been around since the 1950s. It was first used for soil-settling under buildings and later refined to address tricky subsurface conditions with roadways, Rizzutto said.
Cause for celebration again, perhaps, on Route 52.