Concerns Raised Over Coliseum Construction

The Los Angeles Memorial Coliseum’s new press box--spanning nearly half the length of the playing field and jutting out across hundreds of seats--was built with problem-plagued welds that raise doubts about the structure’s safety, interviews and records reveal.

“I wouldn’t sit anywhere near that Coliseum press box,” said Cecil Farrar, an inspector on the publicly funded project. “I know what’s in it.”

What Farrar saw--and inspection documents confirm--is that welds important to the structure’s strength kept fracturing in a San Bernardino steel shop. This phenomenon, known as delayed cracking, can occur weeks or months after the welds are made if the materials or work fall short.

Experts say delayed cracking is a warning that even welds with no detectable flaws might be brittle, undermining their ability to withstand seismic stresses.

One of those experts is John F. Hall, an associate professor of engineering at the California Institute of Technology and a specialist on the seismic performance of steel buildings. After studying voluminous construction and inspection documents obtained by The Times, he concluded that the press box needs top-to-bottom testing.

“There is reason to doubt that the welds supporting the structure are going to perform adequately in a strong earthquake,” said Hall, an advisor to the White House Office of Science and Technology on national earthquake strategy.

The project’s chief engineer, responsible for overseeing the press box construction, said he had no idea that delayed cracking had occurred because no one alerted him. Had they done so, Brent Nuttall said, he would have reassessed his design and the materials being used.

“I don’t know what to say,” Nuttall remarked when informed of The Times’ findings. “I didn’t know about any of this.”

Companies involved in the work acknowledged that delayed cracking occurred but said they believe that the problems were repaired and reinspected.

“All workmanship meets the requirements of the contract. We aren’t going to ship it [out of the shop] if we don’t feel that way,” said Roger E. Ferch, a civil engineer who is vice president of Herrick Corp., the parent of San Bernardino Steel, where the cracking was observed and documented by inspectors.

Top officials of the project’s inspection firm, Smith-Emery Co., defended their decision not to alert the engineer to the welding problems. They said it was unnecessary because cracks spotted by their inspectors were repaired and often retested with ultrasound equipment.

Smith-Emery President James E. Partridge said that although there was abnormal cracking during the project, he believes that no “major defect” wound up in the completed press box. He said his firm--which was deputized by the city of Los Angeles’ building department--is willing to test the facility to verify its safety.

“If we’ve got any kind of a problem,” he said, “we’re going to get it fixed.”

Construction of the press box marked the final phase of a sweeping renovation of the Coliseum, badly damaged by the 1994 Northridge earthquake. Nearly $100 million in federal emergency money was poured into the overhaul--a touchstone of the Clinton administration’s resolve to help Los Angeles rebuild.

The renovation of the Coliseum, which is owned by the city, county and state, was headed by Tutor-Saliba Corp. It hired a Gardena firm, Washington Iron Works, to erect the press box at the Coliseum. San Bernardino Steel was brought aboard to provide major welding at its shop.

From the beginning, a sense of urgency permeated the press box construction. Contractors strived to meet deadlines. City officials allowed construction to move forward without approved blueprints. The goal--getting the facility ready for USC’s 1995 football season--was achieved.

Since then, officials have been allowing the media to use the structure, and the public to sit under it, even though the inspection firm has balked at certifying that the steel work was performed properly. For that reason, the city has yet to issue an occupancy permit.

Partridge of Smith-Emery said he will not formally vouch for the work until the structural engineer signs “a letter of responsibility” saying that “the as-built condition is adequate to meet [his] design.”

As he waits for that letter to arrive, events continue at the Coliseum and have included seven USC games and at least half a dozen soccer matches.

The strength and quality of the welds are critical to the engineer’s design of the press box. Forty yards long, the box stretches across more than 600 seats and has room for scores of people inside. About half the structure’s weight is suspended from a line of vertical steel columns and diagonal supports, joined by welded connections.

Without comprehensive strength testing, it is impossible to determine the extent to which the welds may be unsafe. But eyewitness accounts of what happened in the welding shop--supported by public and private documents--provide reason for concern.

Among other things, The Times learned during a three-month investigation that the weld on an integral component called a “wing plate” broke of its own weight in the shop. The 1,000-pound piece was repaired so many times that construction specialists believe the strength of the completed weld could have been compromised.

In another instance, an inspector and welder suspected that a crack had developed under some thick steel plates at a juncture crucial for the structure to withstand earthquake forces. But they did not remove the plates to confirm their suspicions--and the questionable steel now helps support the press box.

Problems also existed in tracking whether welds that had been classified by inspectors as defective were ever fixed. For instance, no records are on file to verify whether more than 40 welds rejected by inspectors were repaired before they were installed in the press box.

Moreover, requirements specially created by the structural engineer to help ensure that the welds would not be undermined by delayed cracking were not followed to his satisfaction, records show.

“We had big problems on that job,” inspector Dennis Johnson of Smith-Emery said of the press box construction.

Beyond all the cracks that were identified and repaired, inspectors warned Smith-Emery management that others may have escaped ultrasound detection before shipment to the Coliseum.

“If the crack isn’t oriented right, you can’t pick it up,” said Johnson, one of two inspectors stationed at San Bernardino Steel. “I even told [the inspection supervisor], there was a crack one day and I could see it. But the UT [ultrasound test] wouldn’t pick it up. . . . I said there could be other problems in here that we can’t see.”

Smith-Emery officials said they were informed of this and other problems but did not feel a responsibility to notify the engineer because the contractor was repairing the troubled welds.

The inspectors’ concerns about cracking were shared by San Bernardino Steel’s swing-shift foreman at the time, Darrell Schuman. “I wouldn’t give my worst enemy tickets under that press box,” Schuman said in an interview.

Schuman has alleged that San Bernardino Steel supervisors advised employees that it was all right to physically cover up defective welds in projects, including the press box and a state-of-the-art hospital under construction in Colton.

That accusation was contained in a videotape made by hospital project inspectors, concerned about San Bernardino Steel’s welds. County officials in December provided the tape to the San Bernardino County district attorney, triggering an investigation that has yet to be concluded.

On the tape, Schuman said:

“I’ve never had to work iron in such a way that I’d have to wonder whether or not the thing’s going to stand the next day--or whether or not the press box is going to fall off the Coliseum--from some of the things I’ve seen that went on in the shop. The hiding of cracks, to me, is just a very terrible thing.”

Schuman was fired in December, a week after executives from San Bernardino Steel were shown the videotape.

Company representatives say they have found no substantiation that employees have been authorized to cover up defective welds.

According to the company’s vice president, Schuman was demoted before the videotaping because of the swing-shift’s production and quality of work. The firm’s lawyer said Schuman later was fired because he refused to take a drug test after a workplace injury to his hand.

Schuman said he was demoted for cooperating with inspectors and ordering time-consuming, costly repairs. He refused to submit a urine sample, he said, because he considered it harassment. Schuman said he does not drink or use drugs.

The district attorney’s investigation remains open but is winding down, according to the prosecutor in charge of the case. “Some [welders] have indicated, yeah, there were some problems,” said Deputy Dist. Atty. Glenn Yabuno. “Others said just the opposite.”

Regardless of Schuman’s employment dispute, inspection reports and interviews make clear that he is not alone in questioning the quality of the press-box welds.

No weld failure was more dramatic during construction than the snapping in June 1995 of one of the 14 wing plates that provide important support for the press box.

The newly welded connection was being turned skyward when the plate suddenly broke free.

“I’ve never seen anything like it,” said inspector Farrar, 65, who retired from Smith-Emery last summer after working more than 40 years in the structural steel business.

The problems did not end there. Because of repeated cracking from the reheating and cooling associated with the welding, those who observed the work said it took welders several attempts to re-weld the plate.

Similar though less extreme difficulties were encountered during the welding of at least four other wing plates, according to ex-shop foreman Schuman and the inspectors.

“They kept snapping and snapping and breaking and breaking,” Schuman said of the attempted repairs. “By the time it got finished . . . you’ve welded the things four times.”

The inspectors noted the failure of the first wing plate and other fractures in handwritten reports--some of which were kept in Smith-Emery’s private files.

“There is a real problem with delayed cracking,” Farrar concluded in a June 17, 1995, report.

Ten days later, Johnson reported that there were “many problems during shop fabrication of this job. . . . Cracks we discovered were removed and rewelded . . . but again delayed cracking could occur.”

The vice president of San Bernardino Steel’s parent company said he was made aware of the severe wing-plate crack but was not worried because it had been fixed. “The fact that it happens,” Ferch said of the cracking, “is not that unusual.”

Asked whether the strength of the plate could have been compromised by the repeated re-welding efforts, Ferch said: “Not necessarily. . . . The force and the stress that’s on the steel during the welding process, it’s greater, normally, than anything it will ever see after that.”

Hall of Caltech says otherwise.

“What’s it good for after they re-welded it over and over? It’s impossible to say with certainty,” Hall said. “You could have a tremendous decrease of capacity.”

Hall said the cracked wing plate should have been a warning to everyone involved in the construction.

“Think about it,” he said. “That’s a weld you want to hold up your building in an earthquake. And there it goes--in the shop, under what are supposed to be ideal welding conditions. It blows your confidence. You would want to reassess everything.”

Questions also surround another welded connection, one that Farrar and Schuman worry is now sitting cracked in the steel structure supporting the press box.

Although they did not see the crack, they thought they heard it--a distinct sound resembling gunfire. “Rifling” is what it’s called in the steel trade.

“When you hear it, you know it. . . . You know you’ve got a problem--and you better start looking for it,” Farrar said.

That sound rang out in one of San Bernardino Steel’s hangar-sized workshops not long after the cracking of the first wing plate. Farrar and Schuman, who were standing nearby, combed an assembly under construction but could find no crack. Farrar then used his ultrasound machine. Again, nothing.

This meant that if a crack existed it probably was concealed by half-inch-thick steel plates covering the connection of a horizontal beam to a vertical column. This connection is in an area where the structural steel would be called upon to transfer earthquake stresses into the foundation.

Despite the importance of the connection, Schuman said he was under general instructions from superiors not to disassemble or fix something unless a weld defect was visible or a repair was ordered by an inspector.

Schuman’s understanding was consistent with San Bernardino Steel’s wishes. Company Vice President Ferch said that although he was unaware of the rifling, it is generally unnecessary to remove plates to search for a cracked weld. “The normal policy, I would say, would be to recheck it from the outside [with ultrasound],” Ferch said. “It is not normal practice at all to go back on inside.”

As for the on-site inspector, Farrar, he said he believed his bosses would not have wanted shipment of the steel blocked.

“The best thing you can do,” he said, “is note it on your paperwork. The engineer needs to be apprised of it.”

But at least one of his superiors said, in hindsight, that the situation should have been handled differently.

“If they can’t find the crack on the exterior, then they’re going to have to open it up,” said Smith-Emery Vice President Edward C. Trasoras, who added that he did not know about the incident.

Even when weld cracks or other defects were identified in the shop, documents and interviews raise the possibility that some were not repaired.

On one inspection sheet, 41 welds were rejected. No inspection records are on file to verify that they were fixed.

Ferch of the Herrick Corp. blamed inspectors for perhaps failing to document the repairs. “Normally we will repair it before it ships,” Ferch said.

The inspection firm’s president said that although his company did its best, some of the defective welds may have been transported to the Coliseum, ending up in the finished press box.

“It is our intention if something is rejected that it be repaired and subsequently accepted,” Partridge said. “And there’s no question about it, when you ship to a different location and you have a different [inspector] involved, you do run the risk of missing something.”

Smith-Emery’s primary inspector at the Coliseum, Terry Wilson, declined to be interviewed. Another on-site inspector, Mark Hughart, said only that steel problems he saw were corrected.

The president of the company responsible for erecting the press box in the Coliseum, David Welsh of Washington Iron, said there is a “good likelihood” that defects not repaired in the shop were fixed in the field.

The project’s general contractor, Tutor-Saliba, was unaware that delayed cracking occurred, according to the company’s president. “It never came to my attention,” said Ronald N. Tutor.

Despite the large crowds at Coliseum events, the project engineer was not informed of these many problems. Not the wing plate. Not the rifling. Not repairs to so-called continuity plates, intended to provide extra seismic support.

“I would have liked to have known,” said Nuttall of the firm Nabih Youssef & Associates.

Experts say that when delayed cracking occurs, it should prompt a reassessment of the materials and welding processes. During an earthquake, even cracks invisible to the eye can knife through a weld and into the steel itself.

“Delayed cracking is an indication of the welding process being out of control,” said Steven J. Jorgenson, chief welding engineer for the Pasadena-based Parsons Corp. “It’s not normal.”

Delayed cracking can occur for a variety of reasons, including the presence of impurities in the welding material or the steel to which it is fused. Engineers say that proper preheating of the steel and the selection and handling of the welding material can help prevent delayed cracking.

In the case of the press box welds, a number of the problems with delayed cracking were documented on reports kept inside the inspection firm under the handwritten heading, “For Smith-Emery Files Only.”

Asked why those observations were not disclosed, Smith-Emery President Partridge said: “If we turn this out as a report, somebody’s going to make an issue out of it. And it doesn’t matter. All we can say is, either [the weld is] acceptable or rejectable.”

But Farrar, whom Partridge called an “A-plus” inspector, disagreed.

“Myself, I think it’s only right to make the engineer cognizant of the fact that we’re having problems with delayed cracking and repeated cracking. . . . You write these reports and you wonder if anybody ever reads them.”

The Smith-Emery reports prepared for outside distribution excluded the inspectors’ handwritten observations of delayed cracking. For the most part, the reports focused on the general nature of the work and whether procedures were being followed. The documents were intended for the engineer, the city building department and the Coliseum Commission’s renovation manager, Don C. Webb, who said he was unaware of any problems.

Smith-Emery’s decision not to fully apprise the engineer of cracking problems at San Bernardino Steel has led some insiders to question the relationship between the two companies.

Although Smith-Emery functioned as a “deputy” inspection arm of the city of Los Angeles, it has other business with San Bernardino Steel’s parent company, Herrick.

Partridge confirmed that Herrick selected his company to inspect structural steel provided for a recent hospital job in Anchorage, Alaska, as well as for other projects “generally out of the state.”

These projects, he said, amount to “less than 5%” of the inspection firm’s annual billings and do not sway decisions in Herrick’s favor. Ferch of Herrick said neither company would compromise their standards. “Both sides have too much to lose,” he said. Herrick is among the nation’s largest steel fabricators.

That the cracking problems with the press-box welds were not shared with the engineer was ironic. In his plans and inspection standards for the project, Nuttall had attempted to respond to the fact that more than 200 steel-framed buildings in the Los Angeles area had suffered cracks during the Northridge earthquake. Aware of this danger, Nuttall had placed a premium on seismic safety.

For instance, he helped develop welding procedures specifically for the Coliseum press box and directed that they be in the hands of every welder and inspector. This was not fully complied with, as noted in a June 1995 inspection report: “All Welding in Progress Without Approved Welding Procedures.”

Ferch of the steel company said he was unaware that the approved welding procedures were not in place. “There is no concealing or hiding of welding procedures within Herrick,” he said, adding that the company has upgraded its quality assurance manual in response to the Northridge quake.

Nuttall also imposed a requirement intended to better detect delayed cracking. Although not mandated in building codes, he wanted the press box welds to cool for at least 48 hours before being subjected to ultrasound testing. This interval was aimed at giving inspectors a better chance of seeing whether delayed cracks would develop before the steel was installed at the Coliseum.

But within days after the welding began, the contractors complained that the requirement was excessive and persuaded Nuttall to drop the time to 24 hours. Even then, pieces were shipped before that time had elapsed.

A Smith-Emery executive noted this in a memorandum prepared after the press box was completed. In it, he said the reduced time period was “violated many times.” Nuttall’s engineering firm concurred, writing in a November 1995 overview of the construction: “Compliance with the waiting period for ultrasonic testing was not met on several box columns.”

Ferch of Herrick said that San Bernardino Steel had the authority to ship welds whenever it wanted--before or after 24 hours. What mattered, he said, was whether the steel was available for ultrasound testing once it arrived at the Coliseum.

“All you’re going to be worried about then is any delayed [cracks] that show up,” Ferch said. “And is that an acceptable level of risk to take? Yeah. Is it in violation of the contract? No.”

But the early shipping of the steel made inspection more difficult, according to the president of Smith-Emery.

“This was one of the things we had trouble with on that job,” Partridge said. “We hate to see it. . . . But I can’t do anything about it. We have to pick the battles we want to fight. . . . It would have been easier [and] less confusing for us . . . to work off the shop floor [than] to crawl up the ladder [at the Coliseum].”

In addition to his other seismic precautions, the engineer required that special testing be conducted on welds made during the press box’s assembly at the Coliseum. He believed that this was necessary to assess their strength and whether they contained elevated levels of hydrogen, which would indicate vulnerability to delayed cracking.

Again, in much the same way he had been frustrated on the welding procedures and the time delays, Nuttall’s instructions were not followed for the strength testing.

“If I had my way,” the project engineer said, “it would have been done better.”

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

WORRISOME WELDS

The Los Angeles Memorial Coliseum was badly damaged by the 1994 Northridge earthquake. With $99 million of federal emergency funds the stadium was refurbished. The last phase was erection of a new press box in 1995, before the fall college season. Built with an overhanging design, the structure relies on a succession of thick steel welds. Records and interviews call into question the reliability of those welds and whether the structure is safe.

THE STRUCTURE

Crucial connection: This important connection--a wing plate--snapped in the shop after it was welded. The piece was re-welded repeatedly, before inspectors approved it.

“Rifling”: Rifling is a term referring to the loud, jarring sound that often indicates a weld has cracked. Rifling was heard in the shop during construction. In this instance, the enclosed connection was not opened to verify if or where weld cracking had occurred. For this reason, those involved fear that a crack at this connection may have been built into the structure.

More than 600 seats are located directly below the newly constructed press box.

DELAYED CRACKING

Delayed cracking--cracks occurring during or after cooling--was a problem in wing plate welds that support the structure. The diagram below explains shrinkage complications in wing plate welds:

1) Top side of steel wing plate is welded to steel flange.

2) As the initial weld cools, it shrinks, causing the plate to tilt toward shrinkage.

3) Opposite side is welded and shrinks as it cools. Plate tilts toward new weld, which puts tension on first weld, cracking it.

4) Due to crack, first weld is ground out to be re-welded.

5) First weld is re-welded. As it cools, it shrinks, tilting plate back toward re-weld. This puts tension on the second weld, cracking it.

6) In some instances, this cycle occurred three of four times before inspectors approved the weld.

CANTILEVER DESIGN

The press box is a cantilevered structure. The back side is anchored into the concrete of the stadium. The overhang is the cantilevered part.

The overhang is supported from above, by the roof truss. The roof truss transfers the weight of the overhang up and around into the concrete base on the back side.

In supporting the weight of the overhang, the diagonal roof truss components stretch, and the vertical box columns compress. These forces are transmitted between the pieces of the structure through the wing plate connections. Take away the wing plates, and the overhang loses its support.

Source Los Angeles Times

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

The Documents

Inspection reports obtained by The Times reveal numerous problems that emerged during construction of the new press box at the Los Angeles Memorial Coliseum.

Among the findings:

* In an effort to detect “delayed cracking,” the structural engineer originally required that non-destructive testing (“N.D.T.”) not be conducted before the welds had cooled for 48 hours. This document shows that testing was done much earlier.

* The engineer, aware of structural cracking associated with the Northridge earthquake, required that all welders and inspectors be given approved welding procedures he had helped create. This document shows that his order was not fully complied with.

* Throughout the press box project, cracks plagued a number of welds, including continuity plates, which are important for earthquake protection. This previously undisclosed document sounds a warning.

* Inspection document shows that continuity plates with 41 welds were rejected in the shop--with no record of repair. Executives of Smith-Emery, the inspection firm, say that any rejected welds shipped to the construction site were supposed to be repaired there. However, no inspection records are on file verifying repair of these welds.

Source Los Angeles Times