Linda Rose was commuting home from UCLA through the Sepulveda Pass in December 2011 when she noticed that several panels of a tall retaining wall just west of the 405 Freeway had crumpled.
"It was like it was there the day before, and it wasn't there now," she said of a portion of the 40-foot-high structure near Mountaingate Drive. "It was a brand-new wall, which makes you kind of wonder."
Engineers traced the problem to faulty materials. Crews soon went to work dismantling and rebuilding that wall and 14 others under construction along the 10-mile route of the epic 405 widening project.
The wall failure was just one of several snafus that have delayed construction and added about $100 million to the project's original billion-dollar price tag. Other problems have included contested rights-of-way, design changes and the time-consuming relocation of multiple underground utility lines.
There is debate about who is to blame for the problems. Transportation and construction officials are expected to take months to resolve who bears responsibility and how much of the cost overruns taxpayers will have to cover.
Public works contracts for big projects like the 405 typically include penalties for delays. The original contract with Kiewit, the main 405 construction firm, called for the project to be completed at the end of this month.
Delays and change orders, however, postponed the assessment of penalties.
Kiewit and the Los Angeles County Metropolitan Transportation Authority, which is running the project, are completing "time-impact" analyses to determine responsibility for the construction issues that led to the delays and cost overruns. Once those evaluations are finished, the parties will negotiate.
Settling such disputes "is a very prolonged process," said Krishniah Murthy, Metro's executive director of transit project delivery.
The 405 project is being built under a speedier-than-typical process. State lawmakers fast-tracked the construction by choosing the so-called "design-build" method over the more traditional "design-bid-build."
Design-build puts a single contractor in charge of final design and construction, in theory enabling projects to run more smoothly and to be completed at lower cost.
Shaving years off the project "saves hundreds of millions of dollars in construction impacts, costs and travel delays for the public," said Dave Sotero, a Metro spokesman.
But there can be downsides to this approach.
Some tasks that normally would be completed before the bulldozers and pile drivers move in — such as relocating utility lines — must be completed while construction is underway. Nasty surprises can derail plans.
In addition to completing the northbound HOV link between Orange County and the San Fernando Valley, the 405 project has entailed building new onramps and offramps, demolishing and rebuilding three bridges and adding miles of walls to hold back earth or buffer freeway noise.
Many types of walls have been built along the route, with names that only an engineer could love: soil nail, tie back, soldier pile, cast-in-place concrete. The one that ruptured near Mountaingate was a mechanically stabilized earth, or MSE, wall buttressing the new onramp from the Skirball Cultural Center to the southbound 405.
MSE walls are used because they can be installed quickly and easily. The face of an MSE wall is typically made of precast panels that are installed horizontally. Workers then backfill the space behind the panels with compacted soil and other materials. At specified levels, workers lay reinforced steel mesh that is hooked to the wall in some way to hold the wall in place.
Kiewit said it traced the problem to the original system of steel mesh and hooks used to hold the panels in place. It is battling in court with the supplier of those materials. In Kiewit's view, "these issues have not delayed the completion of the project." Metro says the matter is being evaluated.
Even before the wall slid, Metro was involved in its own legal battle over an easement. Because of that tussle, construction on one set of ramps — near the Getty Center — will be put off until the rest of the project has been completed.
In March 2011, Giro Properties, a limited liability company, alleged in court documents that Metro, the California Department of Transportation and Kiewit had intruded on an easement that the company had procured in 1986 for access to a prospective Moraga Canyon golf course and residential development. The lawsuit was dismissed last year after transportation officials stopped construction activities and agreed to find new locations for the Getty ramps that would not cut across the face of Giro's easement.
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