Slides Reinforce the Point That Engineering Matters
When a thundering crash awakened Bruk Vandeweghe in the predawn hours of Feb. 12, he pictured an airplane slamming into the bluff beneath his house on a Culver City hilltop.
Vandeweghe, a former professional beach volleyball player, hustled to a picture window overlooking his backyard.
The accustomed panorama was there, from Playa del Rey to Hollywood.
Much of his backyard was not.
The sound that Vandeweghe had heard was that of gunite cracking and a huge concrete retaining wall splitting, as heavy rains caused slides on the 80-foot-highbluff.
The resulting damage rendered his 50-year-old house uninhabitable -- red-tagged, at least for the time being. Neighbors on each side of him suffered a similar fate. But three houses next to them rode out the storm without a serious problem.
The hillside beneath the three undamaged properties had been buttressed by expensive wooden walls anchored into the earth with steel beams, erected by Culver City officials in the mid-1990s with money from the Federal Emergency Management Agency.
The rest of the bluff, including the area beneath Vandeweghe’s home, was protected by a much cheaper -- and weaker -- reinforcement of sprayed-on gunite: a mix of cement, sand and water.
As officials continue to assess the damage done to homes by this winter’s rainstorms across Southern California, patterns are beginning to emerge that explain why some houses sustained serious damage and neighboring ones did not.
Many of the most severely damaged homes were built before 1963, when the Uniform Building Code began to undergo changes aimed at protecting hillside homes from landslides. Many were in areas with a known history of slides.
And some, like Vandeweghe’s, were in places where consultants had proposed specific, expensive safety measures -- advice that had been ignored or only partly heeded.
The preliminary evidence suggests that homeowners, developers and city officials ignore such recommendations at their peril.
Given the ferocity of the storms that have battered the Pacific Coast in the last month, building officials and engineers said they were surprised that so few homes failed. Out of 12 million in California, fewer than 100 were red-tagged as a result of storm damage. Roughly 100 received yellow tags, indicating restricted occupancy.
“In Los Angeles and California as a whole, we have some of the strictest codes in the country -- and the world,” said Hank Koffman, an engineering professor at USC. “It may not be 100% perfect -- there are geological reports that miss or don’t address every problem -- but if we didn’t have such strict codes, we would have had 100 times the damage we had.”
Greg Axten, a geotechnical engineer, recently assessed homes from San Diego to San Bernardino that had been red-tagged as a result of the rains. He said he found common problems -- steep slopes, poor drainage -- but also evidence that the damage could have been prevented.
“You can properly design against these problems,” said Axten, principal engineer and chief executive officer for Yorba Linda-based American Geotechnical Inc. “Those things that get overlooked tend to cause big problems down the road.”
A case in point: Anaheim Hills, where homeowners treasure sweeping views of north Orange County. Three multimillion-dollar homes were destroyed this month by a slow-moving landslide.
Unlike many homes damaged in the region, these were new. City engineering records indicate that they had been built within the last four years. But none was on concrete support pilings, known as caissons. Surrounding homes that had such pilings weathered the storms without problems.
Most homes in the gated neighborhood were built in the early 1990s by Taiyo Investment. The company had intended to build houses on all 49 lots in the subdivision.
A geologic study completed in 1987 for the developer by GeoSoils Inc. found that soils put down during grading done in the 1970s were not stable enough for conventional concrete slab foundations. As a result, geologists recommended that the homes be built on caissons sunk into at least 2 feet of bedrock.
“The concrete slab-on-grade is not recommended for the building floor, except the garage floor,” the report said.
A slow housing market prompted the company to halt before all the homes were built, selling several empty lots on the western edge of the subdivision to individual buyers.
More than a decade later, new owners applying for grading and building permits had to submit updated geology reports. They hired their own geologists, many of whom wrote reports that conflicted with previous assessments of slope stability and foundation requirements, records show.
For instance, in 2000, soil engineers from Soils and Geology Inc. were hired by the owner of 365 Ramsgate Drive -- the first home to begin sliding in the recent storms. Its report said that bedrock, along with fill soils laid during the 1970s, “will provide good foundation support.” There was no mention of caissons.
Somewhat similar assessments were provided by other firms, Norcal Engineering and Environmental Geotechnology Laboratory, to the owners of two adjacent homes.
Of the three consultants, only one, Frank Stillman of Soils and Geology Inc., could be reached for comment last week. Stillman said he had never seen the original recommendation for caissons and defended his conclusion that the soil was stable.
“You don’t get a failure like that in soil,” he said. “It’s a bedrock failure."In the end, the three homes that slid all lacked support pilings.
Anaheim officials approved the geologists’ recommendations. Natalie Meeks, the city’s development services manager and civil engineer, said Anaheim relies on the private geologists hired by property owners to determine how best to deal with the potential for landslides.
For the most part, the city doesn’t have the resources to independently verify whether the recommendations are sound or to go back through old geological reports to see if they conflict with the current geologist’s conclusions, she said.
Anaheim officials have contended that the city is not liable for the homes falling because the slide occurred on private property.
In the case of Culver City, it was the city itself that undertook the hillside stabilization. Three times, the city stepped in. Geologists studied the bluff and made recommendations. But each time, the fixes turned out to be measures that did not fully work.
“The city needs to come in once and for all and do a permanent fix,” said Vandeweghe, a newlywed who bought his 1,500-square-foot home for $855,000 last fall. He is the brother of former UCLA and NBA basketball player Kiki Vandeweghe.
Vandeweghe shares the bluff in the northwestern Baldwin Hills with six other homeowners. The houses were built in the 1950s.
City engineering records, which Vandeweghe reviewed before he bought his house, show erosion problems developing in the 1960s.
A severe storm in 1978 caused mudflows and collapsed a retaining wall, apparently prompting the city to hire the first of its outside consultants.
The consultant recommended a series of improved retaining walls, which were built with a concrete apron extending over part of the slope. Portions of the apron were undermined by heavy rains in 1985.
Walt Shubin, who has lived on the bluff for nearly 30 years, recalled that homeowners hired a lawyer but, rather than sue the city, worked out a deal in which they agreed to pay 10% of the cost of stabilizing the bluff, while the city paid 90%. The city’s chief interest lay in protecting a road that ran beneath.
In 1987, the city turned to another geological consulting firm, LeRoy Crandall and Associates, which proposed a number of approaches. One relatively expensive solution, priced at $600,000, involved building walls with beams, known as soldier piles, driven into the ground and stabilized with anchors driven horizontally deep into the bluff.
The city and the homeowners went with an alternative estimated at $150,000 that involved building 10 terraced fences up the bluff. The fences consisted of vertical pipes connected by boards. The pipe-and-board terraces were finished in late 1990 after two years of construction.
They failed during heavy rains in 1993.
This time, the city turned to a new consultant, Kovacs-Byer and Associates, which recommended the wooden walls in place today.
City officials received $744,000 from the Federal Emergency Management Agency for the project and spent $698,000 of it on the three tiered, anchored walls beneath those sections of the bluff that had experienced the most severe slides.
For the rest of the bluff -- which included Vandeweghe’s house -- they said all they could afford was gunite.
That lasted until this month.
Landslides are a natural part of Southern California’s landscape. At early stages of the area’s development, few builders thought much about geology. Homes were plopped onto the hills, often barely anchored into land that sat above ancient slides. In some cases, the land was still moving -- so slowly that homeowners didn’t realize it.
Because of that reality, Los Angeles’ building codes have evolved over the last 50 years into some of the most stringent on the planet. Each storm, each earthquake, each mudslide imparts new lessons to city planners and building officials, geologists say.
In 1963, for example, the city established what were at the time strict standards about the way hillsides were graded in preparation for building, in a bid to make them less likely to slide.
“The Southern California area has a large amount of sloping land that is very susceptible to landslides,” said Randy Jibson, a private geological consultant. “But many places can be developed if you develop them with a knowledge of the issues. The problem comes when there is an insufficient understanding of the underlying geology.”
Bob Steinbach, a spokesman for the Los Angeles Department of Building and Safety, said damage from the mudslides was less serious than in other regions experiencing similar rainfall.
Moreover, he argued that homes were damaged by freakish weather and because they were constructed before more modern building standards were in place.
Still, former State Geologist James Slosson said he believed that the current test to determine the soil stability of a property -- sometimes digging just 5 feet into the ground -- was not tough enough because it might miss multiple slide planes farther from the surface.
“It doesn’t provide enough information to determine whether you have a safe and stable building site or not,” he said.
In Los Angeles, city officials said Friday that 89 homes had been red-tagged after the storms, but addresses were available for only 72. Of those, city records show, 69 were built before 1965 and 28 before 1950. Many showed signs of geologic instability 10 or 20 years ago.
“None of the newer structures suffered major damage,” said Steinbach. “None of [the red-tagged structures] had the benefit of the new technologies and new standards that we use now.”
Insurance generally doesn’t cover landslide damage, and homeowners may have a tough time suing anyone for damages. Total damage to the homes has been estimated at $12.23 million.
“Sometimes,” said landslide lawyer Edward Burg, “it just rains so much there is nothing you can do to recover the loss. You can’t sue God.”
Robert and Patricia Prole’s ranch home in the northeast Los Angeles neighborhood of Highland Park was built in 1967, on a bluff overlooking the Arroyo Seco flood channel. They bought the home in 1997.
During the January rains, a minor slide occurred on the slope below the Proles’ yard as well as on a nearby slope.
Their home and their neighbor’s, on a cul-de-sac called Fortune Place, had a history of problems dating at least to 1978. City building files are filled with geologic inspection reports and urgent warnings about the instability of the soil beneath the properties.
One report refers to a 1978 slide and concludes: “We have therefore recommended correcting the existing damage and taking efforts to minimize future damage as the only practical solution.”
That report was followed by several warning letters from the city Department of Building and Safety demanding that the owners shore up their properties and improve drainage.
The Proles said they knew little about their property’s troubled history when they bought it -- only that there had been a problem in the 1970s.
Last Monday, at 1 a.m., they heard a crash. Robert Prole said he opened the back door and peered into the rain. His dog, Fred, ran onto a porch in the backyard. Prole thought something looked wrong -- the landscaping at the rear of the yard was no longer there.
“That’s when I knew something had happened,” he said.
What happened was that about 40 feet of his yard had slid away, coming to rest 100 feet below. A hill above his home also failed. His new swimming pool and Jacuzzi -- which the city permitted him to build in November at a cost of about $50,000 -- hung off the edge of the yard.
The porch now looked more like an observation deck. His children’s swing set was perched on the edge of the cliff.
“I’ve been here seven years, and I’ve never seen even a pebble roll down that hill until this year,” said Prole. “The hill must have dropped in one huge swoop, and the weight of it took everything out in my yard.”
Prole told his story as he stood in the street, next to his SUV. The city’s red tag -- the size of a movie poster -- was on an outside wall of the home, and yellow police tape surrounded the property. There were skis on the vehicle, but Prole wasn’t going skiing. He happened to grab them on one of his few trips back into the house during the week.
On Saturday, the city gave Prole and about 40 friends and relatives time to remove the family’s belongings from the house. They did it in 90 minutes as L.A. firefighters watched -- in case the rest of the house gave way.
The trauma of the week left Prole ambivalent about moving back.
On Thursday, he had vowed to never again live near the hills. On Friday, he began thinking about rebuilding. On Saturday, he began thinking otherwise.
“We’ve been told we’re not going back in there,” Prole said.
Times staff writers Solomon Moore, Catherine Saillant and Mitchell Landsberg contributed to this report.