U.S. Expands Investigation of L.A. Subway Defects : Red Line: Transit officials, construction firm welcome inquiry and pledge to cooperate with federal agencies.

The U.S. attorney’s office will oversee a federal investigation of construction deficiencies in tunnels of the new Los Angeles subway, sources familiar with the probe said Friday.

The action expands a yearlong FBI investigation of contracting and management practices on the multibillion-dollar Metro Rail project and follows Times reports of defects in the concrete work on part of the Red Line subway.

Federal law enforcement authorities are examining issues related to the subway construction, including the recent published reports and whistle-blower allegations of substandard work in some tunnels, sources said Friday.

“They want to know what went on with those tunnels,” said one source who spoke on condition of anonymity. “They’re very interested in what’s been coming out this week.”

The precise nature of the investigation was not disclosed. Assistant U.S. Atty. Adam B. Schiff, who is overseeing the investigation, declined to comment.

The federal government has provided about half the funding for the $1.45-billion Red Line, and if evidence of wrongdoing surfaces, it would come under the jurisdiction of the FBI and U.S. Department of Transportation, which also has begun reviewing the construction.

Top local transit officials said Thursday that less than half of the reinforcement originally ordered to correct construction defects between Union Station and Pershing Square has been performed.

Franklin E. White, the newly installed chief executive officer of the county Metropolitan Transportation Authority, said: “We absolutely welcome the U.S. attorney’s involvement and will cooperate with them in any way we can.”

An official of Parsons-Dillingham, the company that has overseen the subway construction, also pledged cooperation. “We welcome any investigation of this program by a responsible agency since we feel it will help alleviate any concerns of the public,” construction manager George B. Morschauser said in a statement.

Ronald N. Tutor, whose company built the $89-million segments of subway, said his firm has nothing to fear from an investigation. “Let them investigate,” he said. “The truth will always come out.”

Transit officials Thursday said they had fired from the Metro Rail project a Parsons-Dillingham executive who oversaw completion of the 4.4-mile Red Line subway. They said subway completion manager Stuart Williams overstated the amount of reinforcement work that was performed on the tunnels after numerous thin areas were discovered in the concrete walls.

Williams could not be reached for comment. Morschauser said Williams had made “an honest mistake” in misreporting the extent of steel plating that was installed before the subway’s January opening.

“It is important to note that Parsons-Dillingham discovered late Wednesday that the report (by Williams to MTA officials) was inaccurate, and immediately brought it to the attention of the (MTA) and began further investigation,” Morschauser said. “Parsons-Dillingham . . . stands behind its work and the structural integrity of the subway.”

Transit officials continued to review Friday what they would do to further ensure the safety and structural soundness of the tunnels between Union Station and Pershing Square. Based on new testing of one 15-foot area of tunnel, White said that crews will not--contrary to what he and another executive had said Thursday--immediately install reinforcement in that limited area.

White said he made the reversal based on the results of drillings of the subway walls that were conducted jointly on Thursday night by the subway contractor, Tutor-Saliba Corp., and by Metro Rail’s construction management firm, Parsons-Dillingham.

Several drillings showed that the concrete was at least 10 inches thick, according to Edward McSpedon, president of the MTA’s Rail Construction Corp.

Original design plans required the tunnels to be built with a minimum thickness of 12 inches. A consulting firm’s report in October found that concrete along the 15 feet in question was 6 to 8 inches thick. The thinnest point, according to that report, appeared to be five inches thick.

McSpedon and his staff said they were unable to say precisely where on the tunnel walls the new drill holes were made. The exact locations are important because, according to experts contacted by The Times, sections of a tunnel that are thin on one side are typically thicker on the opposite side.

For now, White, McSpedon and K.N. Murthy, one of the project’s top designers, said they were satisfied that the 15-foot area was safe and structurally sound without further reinforcement.

“They gave us the depth of the concrete where they were drilling,” Murthy said. “Based on that, we ran the (design) calculations. Based on that, we are comfortable.”

White, who took over the MTA five months ago, reiterated that his “main concern is to put to rest any public concern regarding the safety” of the tunnels. White said he still planned to quickly name a three- to five-member task force of independent construction experts to study and report on the soundness of the tunnels along the 1.9-mile stretch.

The Times reported Sunday that numerous sections of the tunnels linking Union Station and Pershing Square were built with less concrete than specified. Radar testing performed for the MTA in August, 1992, found that 2,082 feet, or 21%, of the tunnels may be 6 to 8 inches thick.

McSpedon has said that, based on coring samples taken after the radar testing, he is confident that only as much as 90 feet in three locations needed to be reinforced with thick steel plating. Officials said Thursday, however, that only 40 feet of tunnel--in two locations--had been reinforced. On Friday, McSpedon’s staff said that three areas totaling 40 feet had been reinforced with the plating.

Experts said in interviews that tunnel sections built under design specifications--and not reinforced--would be more vulnerable to stress during a major earthquake. Transit officials initially said that tunnel walls that are at least 10 inches thick, rather than the design-specified 12 inches, still would be safe and sound. This week, they have said that nine inches of thickness would be adequate.

In Washington, Rep. Jerry Lewis (R-Redlands), a senior member of the House Appropriations Committee, warned White in a letter that questions surrounding the tunnel controversy could affect federal funding for the project.

“Continued federal assistance for this transit system may be jeopardized short of a full and thorough investigation relating to the failure of the contractor to properly build and the transit authority to properly enforce critical safety specifications for this system,” Lewis wrote.