Memo raises questions about MWD headquarters' seismic fitness

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In 1996, taxpayers spent more than $100 million on the Metropolitan Water District’s headquarters in downtown Los Angeles. Now, they may be on the hook for millions of dollars more in seismic repairs and upgrades to the building.

Concern over seismic safety at the MWD’s 12-story headquarters first arose about five years ago. That’s when MWD officials noticed cracks in concrete beams in the building’s underground parking garage.

"We believe there were some issues during the construction with the contractor that led to those cracks," MWD Chief Engineer Gordon Johnson says. "The connections between the beams and the columns needed to be stronger."

Johnson says the contractor did not use enough steel rebar where some of the horizontal beams met the vertical columns. MWD fixed the problem by wrapping half a dozen of those connection points with carbon fiber to strengthen them.

The agency also asked a consulting firm to examine all of the building’s hundreds of concrete columns and beams. The results were not good.

ABSG Consulting produced a memo in July 2011 that said its computer analysis found the building "does not meet the original design requirements" for an essential facility. Essential facilities like hospitals and fire stations are supposed to be built stronger than most structures so they can remain functional after a major earthquake.

"There would be a potential for building collapse under sustained strong ground shaking corresponding to a major seismic event," wrote ABSG in its memo to MWD.

"The problem seems to be the beams and the columns do not have enough strength to resist a large earthquake without suffering real significant structural damage," says John Larson, a designer of dozens of large industrial and commercial buildings in Southern California who reviewed the memo. "In some cases the strength is only about a third of what’s needed."

Lawson, who teaches architectural engineering at Cal Poly San Luis Obispo, cautions the memo is "not yet conclusive," and says more testing is needed.

The MWD’s Johnson doesn’t quite dismiss the report, but he says the consultant "did not use the most up to date" computer models and "tended to look at beams in isolation," as opposed to how they would work together with the columns to hold up the building.

"That was an extreme type of result that they came up with," says Johnson. He believes the building is safe.

One of Southern California’s best-known builders, Pankow, designed and built MWD headquarters.

The ABSG memo "doesn’t tell the whole story," says Pankow Chief Operating Officer Dick Walterhouse. "I can tell you the building was built in accordance with the codes applicable at the time."

Walterhouse says a subsequent memo from ABSG and a second memo from another firm call into question the original report’s findings. He says he can’t release those memos because they may become the subject of litigation.

MWD spokesman Bob Muir told KPCC that he doesn't know which memos Pankow is referring to, adding that his calls to Pankow seeking clarification have gone unanswered.

Meanwhile, MWD is conducting a more thorough review of its headquarters, work that includes UC Irvine engineers boring into the concrete.

"A lot of times you core the samples and break it, and you find out they are much stronger than the original designer intended it to be," says MWD Chief Engineer Johnson.

While he is confident the headquarters would not collapse in a major earthquake, Johnson is less certain it meets the "essential facility" standard – which means it could suffer significant damage in a big quake.

"I don’t think that we got the highest level that we paid for. It's something less," says Johnson. "That’s what’s at issue here and that’s what we’ll find out from our test results."

The more in-depth analysis of the building, which will cost MWD $1.5 million, is due out in the next couple of months. 

The agency is anticipating the need to spend more.  It has set aside another $12 million for any repairs and upgrades that might be needed to make sure one of its most critical structures withstands a major earthquake.

The ABSG Consulting memo raising concerns about MWD headquarters. MWD says it did not use the most up-to-date computer models.

April 2013 Power Point by MWD Engineering & Operations Committee



 

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