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Welcome to the world's largest web site on MIG , Flux Cored and TIG. Weld Process Controls & Best Weld Practices. To get to the root cause of GMAW (MIG) & Flux Cored (FCAW) weld issues, requires Weld Process Control - Best Practice Expertise, & lots of Weld Reality. The site provides the MIG - Flux Cored and TIG weld information and data required to attain the highest possible manual and robot weld quality, always at the lowest possible weld costs.
This web site was first established in 1997 by Ed Craig. Contact Ed. ecraig@weldreality.com
California Northridge Earthquake.
57 died, 9000 injured, approx 20 to 30 billion dollars in damages. How much was influenced by poor weld process and weld consumable choices?.
There is much more info available on the self shielded weld wires used in the Flux Cored Sections (Self Shielded Flux Cored)
Structures -- Earthquakes - Human Tragedy - Responsibility Ownership - Liability - Politics - Ethics Poor Engineering Decisions and Poor Weld Wires"
From Ed - Em Craig:
This story has it all. Lincoln Electric, a global, Cleveland, Ohio based company that makes and sells welding products. This is the company that had it's weld consumables tied into the 50 plus lives lost and 20 plus billion dollar damages that resulted from the Northridge CA. earth quake. The weld wires for decades had been selected for numerous California projects. However the weld reality was from a weld engineering perspective, that these consumables were poorly suited for structures influenced by seismic activity. Even on the most simple welds, these consumables typically provided questionable inconsistent weld quality with welds that had typically poor mechanical properties. Also its important to point out that for decades, the so called responsible
engineers and project managers in CA, had made extremely poor weld process decisions, (another reflection on the state of the weld industry).
Engineers were surprised that during the earthquake that buildings that were designed to withstand seismic activity, toppled like the clay homes you see in South America. After the earthquake there was obviously extensive legal, liability and cost ramifications for Lincoln. With those involved in the design - construction welding decisions, there were denials, ignorance, lies and extensive weld process ignorance and confusion. There was also hard to justify donations made to California politicians and at the end the poor old California tax payers got stuck with a large portion of the bills.
It was interesting while all this was going to see lobbyist and FEMA overnight became weld experts and FEMA and Lincoln become friends. Generous grants were provided to a company that did not ask for it and FEMA the same company that screws up when involved in most disasters, got itself involved in Construction - Weld Specifications.
And today in 2015, with no one responsible for the damage, Lincoln is off the hook, and the bovine fecal matter continues as similar poor welds are made daily. I wonder about the 50 plus that died, and I wonder also about those that will die and get injured in the next CA city when the residents are tossed out of their beds. If this was a movie I would call it "
,"The Ohio Fox who was asked to guard the California Hen House"
Who'll pay for L.A.'s shaky skyscrapers?
This was written by Greg Brouwer. 1999 LA Weekly News.
When the Northridge quake awakened Los Angeles on January 17, 1994, it was considered at 6.7 magnitude a relatively moderate shudder. However, because of its location, it was the first true seismic test for many of L.A.'s 1,500 steel-frame buildings. At first glance, most edifices seemed to fare well, but a disturbing trend soon surfaced: Many of the interior beam-to-column connections had cracked, in some cases splitting all the way through. The problem first came to light in structures still under construction, like the Getty Center, which was then just completing steel framing. Engineers there found a series of cracked connections and decided to replace all of its original welds. Owners of completed steel-frame buildings thus learned of the threat, but determining the status of their own welds would require breaking through plaster or concrete just to get a look. Still, the damage had been done - the long-standing myth of the seismic invincibility of steel has been questioned ever since.
THE WELD TESTS SAID ONE THING, LINCOLN , LAWERS AND POLITICIANS SAID ANOTHERShortly after Northridge, the Federal Emergency Management Agency (FEMA) joined several independent firms in conducting tests on the flawed connections. The examinations eventually determined, among other things, that the weld metal was too brittle to withstand severe seismic activity. By the end of 1994, the city of L.A. Issued construction guidelines that effectively banned the use of this electrode product, called a self shielded flux cored wire E70T-4.
Now in 1999, five years after the realization of this fundamental engineering flaw, even as geologists discover new, potentially catastrophic fault lines under the city, a rather ominous question remains: What about those Lincoln self shielded flux cored welds? Nearly all of L.A.'s steel-frame buildings constructed prior to Northridge were built with the weak welded connections. Shouldn't they be repaired?
Some say that the Cleveland-based Lincoln Electric Co, which produced and supplied the self shielded E70T-4 weld wires to L.A. Contractors and builders over the past 30 years, should be held responsible for the questionable welds and poor choice of weld consumables. Executives at Lincoln have another idea. Over the past two years, Lincoln has spent more than $1 million on a quiet, sophisticated lobbying campaign designed to press the federal government to step in and pay the enormous cost involved in retrofitting thousands of welded steel connections in hundreds of buildings across L.A. - and thousands more throughout the quake-prone West.
Lincoln has campaigned in part on its own, but also in connection with Cassidy & Associates, a high-priced Washington lobbying firm. Through the attorneys at Cassidy, in turn, Lincoln launched something called the "Seismic Safety Coalition," (SSC) which purports to be "a broad-based, nonpartisan organization" and a "national coalition," but in fact claims a single dues-paying member - Lincoln Electric.
The "chair" of the SSC commission is Leon Panetta, former congressman from California, former chief of staff at the Clinton White House and longtime associate of FEMA director James Lee Witt. In his capacity as SSC chair, Panetta has registered for the first time as a congressional lobbyist.
As described in it's mission statement, the Seismic Safety Coalition sounds innocuous enough. It seeks to "improve public health and safety by encouraging more vigorous pre-disaster hazard-mitigation efforts with respect to earthquakes." But then comes the punch line: "Specifically, we want to see new developments in earthquake-resistant design and construction practices incorporated in a responsible and effective retrofitting program" -
with the federal government picking up the tab. Government commitment to such a policy could save Lincoln millions of dollars in liability for its welds in Southern California alone.
Just how Lincoln's coalition has gone about pressing its agenda remains unclear - officials at both Lincoln and Cassidy refused to discuss the group, and a half-dozen calls to Panetta were not returned. But one apparent path of action can be discerned in a new federally funded retrofit project in San Bernardino County. In December of last year, engineering specialists at Cal State San Bernardino were informed by the office of Jerry Lewis, the San Bernardino congressman, that they were the lucky recipients of a $5 million federal grant, to be used for "a pilot project of seismic- retrofit technology." And while the university had not asked for the grant, they were told during an informal meeting with FEMA and a Lewis aide that the money would be used to demonstrate the financial and technological feasibility of retrofitting a steel-frame building constructed with Lincoln's E70T-4 weld wire.
Lewis, probably the most powerful member of Congress you've never heard of, sat last year as a senior member of the House Appropriations Committee, which decides how to split up the federal pork pie. Lewis also just happens to be from a seismically vulnerable district and was heavily lobbied for FEMA appropriations by the Seismic Safety Coalition. To complete the circle in San Bernardino, two members from the coalition - one representative each from Lincoln and Cassidy - joined the FEMA crew that met with Cal State officials to lay out the details of the unprecedented $5 million grant.
Comments from Ed Craig.
The Lincoln E70T-4 wire was touted as being a very high weld deposition rate weld wire and therefore that was a key justification for it's use. Keep in mind may of these steel joints were in the past welded with SMAW (stick) electrodes that typically provided approx. 2 to 3 lbs/hr. The change to the ultra high 70T- 4 wires that enabled mechanized welds of > 20 lbs an hour looked great on paper, till you examine the weld quality differences between the stick electrodes and those 70T- 4 wires.It's not mentioned in this report if these wires were used "manually" or were all the welds automated. Its also not mentioned were these wire used for vertical up and manual welds in the field.
The 70T-4 wires are designed to run hot in the flat and horizontal positions. When manual welding, high weld deposition rates would push the manual welder's speeds to levels that would cause weld issues such as lack of weld fusion and high amounts of trapped slag. Keeping in mind also the issues that would result from manual welding idiosyncrasy from one welder to another.
If the E70T-4 was used indoors and solely used with mechanized equipment, it's unbelievable that the fabricators of the structures did not use the superior submerged arc or gas shielded flux cored process. Both of these processes provide healthy deposition rates with weld quality that would have easily have surpassed the seismic requirements.If these wires were used in the field construction there would have been no logic in there selection as these wires are not all position wires and these wires can not deliver welds that would pass minimal impact requirements.
When the wires were used at high deposition rates with mechanized equipment, keep in mind the high currents used, along with the large weld passes, the possible multipass welds, (high weld heat - high trapped slag) and also the likely chance that no inter- pass weld temperatures were used. This , could result in excess weld heat and extended grain growth in the weld's heat affected zones. The poor weld quality and poor mechanical property welds would be tied into weaken HAZ areas along side the welds. The bottom line is this is going to affect the steels mechanical properties especially in seismic activity.
On any critical weld application a logical, knowledgeable weld engineer would select the appropriate weld consumables and stress a conservative to moderate weld settings for the pre-qualified weld data. This pre-qualification procedure would take into consideration the weld and application requirements, and the process controls - best practice training required for those that operate the automated equipment, and those that are manual welders. This did not happen in 1994 and its still not happening in 2014.
THE SELF SHIELDED WELDS DID NOT FLEX OR BEND, THEY SIMPLY BROKE (LACKED DUCTILITY):
John Hall, an engineering professor at Caltech, was one of the first people hired by FEMA to determine why the pre-Northridge connections were cracking. In a lecture later published under the title "Tall Buildings, Bad Welds, Large Earthquakes - Big Problems," Hall explains that engineers had been designing buildings in L.A. on the assumption that, in the event of an earthquake, the building joints would reach an elastic limit, then yield "like chewing gum." What happened with E70T- 4, Hall points out, is that "many welds failed well within their elastic range." The self shielded weld joints didn't bend; they simply broke".
Soon after Hall's study, FEMA committed $11 million to a joint venture called SAC, with the sole purpose of establishing the cause of - and cure for - the defective pre-Northridge welded connections. Robin Shepherd, an engineer with 30 years of earthquake-damage analysis under his belt, is one of six members on SAC's Management Committee. In a 1996 SAC analysis, Shepherd wrote that the damage sustained by buildings constructed under the pre-Northridge guidelines "suggests that collapse of similar structures may very well occur in future larger, but realistically probable, seismic events."
In December 1994, the L.A. Department of Building and Safety issued repair guidelines that effectively banned the Lincoln E70T-4 weld wires by requiring a weld filler metal with a higher "notch-toughness." Two years later, the county followed suit. But while the city has required owners of damaged buildings to make repairs, the undamaged connections - the un-cracked E70T-4 welds in L.A. - remain untouched. "The city does not have a retrofit ordinance," says Richard Holguin, L.A.'s building chief. "There is no plan to modify the existing connections."
Replacing the undamaged but potentially catastrophic pre-Northridge connections is a responsibility that no one is willing to accept. With roughly 1,500 steel-frame buildings in question, a five-story structure may have 300 welds, and fixing each connection can cost between $10,000 and $50,000. That's a lot of welds and a great deal of responsibility.
THE MINUTE POLITICIANS GET INVOLVED THE MORE DIRTY THE WATER BECOMES:
Enter Lincoln Electric, Leon Panetta and the Seismic Safety Coalition. If Panetta and the coalition can convince Congress and FEMA to undertake steel retrofitting as a matter of public policy, then Lincoln will have escaped the question of who should answer for the looming liability encased in L.A.'s steel-framed structures.
Panetta registered with the House of Representatives on March 20, 1998, as a lobbyist for the coalition; his filing states that he was hired by Powell Tate, a public-relations subsidiary to the D.C. lobbying powerhouse Cassidy & Associates. While Panetta and Cassidy refused to discuss the Seismic Safety Coalition, both selections speak volumes about what Lincoln is hoping to achieve.
Panetta, a political insider who once headed the Office of Management and Budget, combines consummate understanding of the budgetary process with excellent contacts throughout official Washington. As regards Lincoln, Panetta's single most important contact is his unique friendship with FEMA director and longtime Clinton tagalong James Lee Witt. Or as Panetta himself put it in an interview last year with the Washington-based Legal Times, "The fact that Witt knows who I am and what I've done is part of the reason they brought me on." Witt, in turn, has established himself as a key player in the Clinton White House. He came with Clinton from Arkansas, and he has transformed FEMA into what many people consider the president's greatest political asset. Indeed, FEMA's relief effort following the Northridge quake represents $13 billion - more than half the emergency funds distributed since Clinton took office. But the tour de force of FEMA's response to Los Angeles came in the form of $126 million to repair and retrofit City Hall. Witt and Panetta joined with Mayor Richard Riordan to share in a conference call announcing the good news. Like Panetta, Witt repeatedly failed to return calls requesting comment for this story.
Lincoln's point man in the effort to secure government cooperation was their top welding engineer, Duane K. Miller. Mr. Miller has been attempting to polish the image of the E70T-4 wire since the first cracks were discovered after Northridge, lobbying local and state officials, as seen in an internal memo written several months before the city's ban on E70T-4 and published by the L.A. Times.
"The fact that self-shielded flux-cored electrodes [E70T-4] have not been banned is evidence that we are on the right path," Miller wrote. "Had we not been present, I am confident that this is one of the actions that would have been taken".
Note from Ed.
Anyone in the weld industry is aware of why we don't weld steel to aluminum. There were numerous engineers, technicians and metallurgists available in North America that could look at the Lincoln steel wire chemistry composition for the E70T- 4 wire and the first thing they would note in contrast to traditional steel welding consumables, is the high amount of "aluminum" in the E70T- 4 wire.
With the unusual aluminum content in the E70T- 4 wire and the important fact that no impact properties were required for this wire in the AWS wire spec, (an indication of weld quality that could be attained from this weld wire) provided a clear message to the weld wires limitations and therfore it's application potential. Also keep in mind that weld wires like this are notorious for slag entrapment and excess porosity, which are also reasons why not to utilize the E70T-4 on welds subject to seismic activity.
Lets face it, most junior weld technicians could have figured out this weld wire was not suited for a seismic structural application. The weld techs would then have figured out on multi-pass welds that the aluminum and other alloy contents and slag entrapment that did not allow the weld wire to be used on impact variable load weld applications, that the aluminum would increase with each weld layer and the resulting multi-pass welds would result with very poor weld mechanicals.
If these wires did what Lincoln said they could do, every pipe line and ship yard would be using them, the fact that the ship building industry and pipe and pressure vessel shops stay clear of these product should have been and indication of their application suitability.
You can be sure the ship yards and pipe lines in CA will not use the self shielded flux cored wires, rather for the all position manual welds, they are likely to utilize the "Gas Shielded" flux cored weld process. For those who state the GAS shielded wires are not suited to welding out doors, I would suggest they spend a day in a ship yard where most welds are affected by the enviroment.
THE RIDICULOUS FEMA FOLLY CONTINUES:
Mr. Miller from Lincoln also sits on FEMA's SAC Project Oversight Committee. Ron Hamburger, chairman of SAC's Guideline Committee, says Miller's "primary role is to provide expert independent advice to our client, FEMA, in other words, one of Lincoln's top men has the authority to determine whether or not the Lincoln's weld consumable being investigated by the federal government is an appropriate choice.
Note from Ed. Expert Advice from a slightly biased point of view.
Some might call this "FEMA asks the fox how it would guard the chicken coop"? And then to add further insult, then ask the fox to write the specification for theFEMAfarmer on how to contain those chickens in the coop.THE COMMITTEE THAT EXAMINES THE ROOT CAUSE OF THE ESTIMATED 20 BILLIONS IN DAMAGES IS BIASED TO THEIR OWN INTERESTS, THIS IS WHY GOD WON'T BLESS AMERICA.
L.A building chief Holguin, who is also on the SAC Project Oversight Committee, claims Miller is a natural choice for the committee because he is knowledgeable about Lincoln's product. However, Holguin concedes, "Let's put it this way - all the committee members bring their own biases to the table."
(Ed's note: Holguin I hope speaks for himself. In my simple world, only an unethical politician or person would bring a bias point of view to a technical committee that will make decisions that impact life and death. By the way I can name dozens of people in this country who are more experienced and less biased on the subject of flux cored welds than Mr. Miller.
Several of Miller's industry associates on the SAC project have heard of Lincoln's Seismic Safety Coalition and are aware of Miller's involvement, but very few have a clear idea of what the organization is up to. In fact, Alan Goldstein, president of the Structural Engineers Association of California, one of the three organizations that compose the SAC venture, had never even heard of the Seismic Safety Coalition. Hamburger is likewise in the dark. "I'm not aware of any members of the organization," he says. "But its purpose was to attempt to get some funding from various government sources to show that it would be possible to upgrade existing buildings."
One apparent political success for the Seismic Safety Coalition came at the end of last year when Congressman Lewis' Appropriations Committee earmarked $40 million for three separate FEMA projects in his home district.
GRATITUDE?Besides Lewis' obvious devotion to the safety of his constituents, another factor in this generous, and unexpected, appropriation may have been the lobbying technique of Cassidy & Associates on behalf of Lincoln Electric and the Seismic Safety Coalition. On March 20, 1998, the same day the Seismic Safety Coalition registered with the House of Representatives, the wives of Anthony Massaro and John Stropki, Lincoln Electric's CEO and executive vice president respectively, made $500 donations to the Lewis campaign fund.
THE CALIFORNIA POLITICIANS THANK CLEVELAND, OHIO RESIDENTS FOR THEIR DONATIONS.
It's not every day that a California congressman impresses well-to-do housewives in Cleveland. Cassidy showed its support to the tune of $6,539, winding up as the 11th largest contributor to Lewis' campaign fund in 1998. And while Sandretti claims that "Senator Boxer did not work for this specific earmark," her campaign fund suggests that Boxer may well have been in the loop. In one day - May 8, 1998 - Boxer received donations from Frederick Stueber, a senior vice president at Lincoln; several key players at Cassidy; and Leon Panetta.
Once again, Cleveland took an interest in California politics, while Cassidy filled the role of one of the largest contributors to Boxer's 1998 campaign fund.Cassidy's bread and butter is the art of earmarking appropriations. Through the years the firm has developed a niche representing universities, hospitals and other private entities seeking to tap into the millions of dollars that flow each year from the congressional spigot. All the various threads of Lincoln's lobbying effort came together on December 10, 1998, at a meeting on the Cal State San Bernardino campus. The meeting was coordinated by Jeff Shockey, the Lewis aide credited with arranging the $40 million in FEMA grants; in attendance were FEMA district coordinator Christina Lopez, FEMA technical consultant Bob Hanson and three Cal State engineering specialists. The idea was "to tell [the Cal State administrators] that they would have to start putting together details for the project," explains Lopez. Also on hand were Duane Miller, Lincoln's weld expert and wearer of many hats, and Jeffrey Lawrence, a representative from Cassidy & Associates. Shockey refused to return numerous calls for this story, as did Miller, so neither could comment on why the two Seismic Safety Coalition members were invited. However, Lopez says, "I was given the impression that Lincoln Electric was going to be working with Cal State San Bernardino on this project."
Surprisingly for a project promising to display the latest technology in welded-steel connections, no one working on the SAC venture, which has been studying the question in great detail over the past four years, has anything to do with it. No one, that is, except Miller from Lincoln Electric. "I was surprised to see him," says Hanson, who knows Miller from overseeing the SAC venture. "I was also surprised to see the person from Cassidy & Associates." Why all the interest from Lincoln in these appropriation funds?
Ed: THE LETS SHIFT THE BLAME GAME IS SO TYPICAL IN THE LAST THREE DECADES WHEN OWNERSHIP, RESPONSIBILITY AND ACCOUNTABILITY IS LACKING WITH THE RESPONSIBLE COMPANIES, ENGINEERS AND MANAGERS..
George Soneff, a Santa Monica attorney currently suing Lincoln on behalf of a Westside building-owners group, is convinced that the retrofit project at Cal State San Bernardino is an obvious attempt by Lincoln to shift responsibility for their faulty welds to the hands of the federal government. "Our lawsuit is the only way that Lincoln can be made to pay for its share of the problem," Soneff said in an interview.
Soneff's suit alleges that during the 30 years Lincoln Electric marketed E70T-4, Lincoln claimed certain weld durability characteristics even though the company "had no reasonable grounds for believing that they were true." He contends that "This type of welded construction didn't happen by accident, but rather it happened as a product of years of "deceptive advertising and deceptive sales techniques by Lincoln."
Note from Ed:
Deceptive advertising, BS process confusion and salesmanship influence in the welding industry, "unbelievable". Some one should build a web site on that subject.
Soneff has an uphill climb ahead of him as he tries to hold Lincoln accountable for E70T-4. Their counsel is Jones Day Reavis & Pogue, the firm that represented R.J. Reynolds in the Great American Tobacco Wars. And that's not all. Remember Robin Shepherd, the SAC earthquake-damage expert, who has a final editing pen in recommendations that go to FEMA and to legislators, who pontificated the quote about L.A.'s probable "collapse"? Well, Lincoln hired Shepherd as an expert witness to the tune of $200 an hour. When Soneff deposed him in early February, Shepherd said he had no opinion about whether there were premature failures in steel-frame welds as a result of the Northridge quake. Soneff then asked him about his alarming quote from two years ago, to which Shepherd replied, "I might point out it says, 'suggests that collapse . . . ' It doesn't say it will happen."
So what about the welds? If the tactics surrounding this current quivering mishap surprise anyone, they shouldn't. Los Angeles, described by our City Council as "the most seismically active zone in the country," could also stand a chance as the most seismically inept. With the scores of aging concrete and masonry brick buildings in the Southland that have never been retrofitted, or even inspected, it's a wonder that steel structures are getting any attention at all.
Following the Northridge Earthquake, the California State Seismic Safety Commission prepared its "Report To The Governor - Turning Loss To Gain," published in 1995.
The magnitude 6.7 Northridge earthquake occurred at 4:31 in the morning of January 17, 1994, on a national holiday, when most Californians were at home asleep. Fifty - seven people lost their lives, nearly 9,000 were injured, and damage exceeded $20 billion.The summary of the Northridge earthquake's impact is 'It could have been a lot worse.' In fact it would have been a lot worse if the earthquake had occurred later in the day and if its duration and intensity had been of the nature anticipated for most of California. (California Seismic Safety Comm., Northridge Earthquake, Turning Loss to Gain, x (1995).
The Report, expressed shock at the performance of steel moment frame buildings which had previously been believed to be the most earthquake resistant construction. The biggest surprise in the terms of building performance from the Northridge earthquake, at least to professionals who deal with seismic design regularly, was the poor performance of steel buildings with moment - resisting frames. Steel buildings have long been viewed as among the most reliable structural systems for resisting earthquakes. They are common for modern high-rises, not only in California but throughout the world. Id. at 65. The Northridge Earthquake raised serious questions about the design and construction of steel moment frame systems. "Fortunately none of the failures resulted in building collapse or loss of life. However, since the earthquake shaking was of short duration, it is an open question as to how the damaged buildings would have performed if the shaking had lasted substantially longer or of stronger intensity." Id. SAC, a joint venture of agencies (Structural Engineers Association of California, Applied Technological Council, and the California Universities for Research in Earthquake Engineering) has issued advisories and interim guidelines for the repair, retrofit and design of steel moment frame structures. (See SAC Joint Venture, Steel Moment Frame Connection, Advisory No. 3, SAC 95-01 (SAC Joint Venture Partnership 1995.) The Northridge Earthquake challenged the assumption that welded steel moment frame connections were automatically capable of extensive yielding without a loss of strength. SAC 1.2.
It was revealed that an astonishing 99% of the brittle weld failures
occurred with the Lincoln "self-shielded flux-core" weld metal.
Thousands of welded steel moment frame connections fractured during the earthquake. SAC 1.2. Once such a fracture formed, the beam-column connection experienced a significant loss of flexural rigidity in capacity. SAC 1.2. In effect, the fractured connection turned out to be a pin connection all along rather than a connection with moment resistive capacity. It fractured when its strength was needed most. Building Inspections After the Northridge Earthquake Many initial inspections of steel frame buildings found only minor damage. After reports of steel moment frame damage began to circulate, engineers and owners revisited buildings to perform more complete inspections. In time, these inspections revealed damage types that had been observed in earlier testing programs. [Popov & Stephen, 1972; Popov & Bertero, 1973; Popov et al, 1985; Popov & Tsai, 1987; Englehardt & Husain, 1993.] It was revealed that an astonishing 99% of the brittle weld failures occurred with the Lincoln "self-shielded flux-core" weld metal. (National Institute of Standards and Technology, NISTIR 5625 A Survey of Steel Moment-Resisting Frame Buildings Affected by the 1994 Northridge Earthquake)In response, the City of Los Angeles passed an ordinance that required the inspection of all beams to column welded moment connections. Los Angeles Cal. Mun. Code §91.8908 (a).
Technical Studies have confirmed that self-shielded flux-core electrodes were a primary cause for brittle weld failures during the Northridge Earthquake. The Center for Advanced Technology for Large Structural Systems at Lehigh University examined the seismic performance of moment frame connections with specimens from the Northridge earthquake. Eric J. Kaufmann, Ming Xue, Le-Wu Lu and John W. Fisher, Achieving Ductile Behavior of Moment Connections, Modern Steel Construction, January 1996, p. 30. Lehigh's published findings concluded that the welds deposited with E70T- 4 electrodes (self shielded flux-cored arc welding electrodes) had very low fracture resistance to moderate earthquakes (less than 10 foot-pounds at 70 degrees Fahrenheit) and are likely candidates for brittle fracture.
The Lehigh study found that brittle weld fractures developed in installations that used E70T-4 welding electrodes with backup bars. The fracture origins were identified at the weld root adjacent to the notch introduced by the backup bar at a location with inadequate root penetration. Kaufmann at 33. In contrast, when a ductile weld metal was used to fabricate a joint (such as the very common E7018 stick electrode), no weld metal cracking occurred and the ultimate strength of the beam plate was developed, that is, it became a moment frame. Id.36.
The E70T-4 weld wire that failed in the Northridge Earthquake was deemed "pre-qualified" by manufacturers and approved for use without performing procedure qualification tests using the weld metal. AWS 1.3.1. The "pre-qualification" assumption continues to this day which does not say much for the American Welding Society. While E70T-4 may perform in a reasonable manner in non-moment frame applications, the Lehigh study has demonstrated that the use of E70T-4 weld metal causes brittle welds in critical moment frame connections: a catastrophe waiting to occur.
Note from Ed:
It did not take a Lehigh study to reveal the welding obvious. The E70T-4 wires did not need an earth quake to figure out the wire chemistry would produce poor weld results when variable loads were applied to the welds. On evaluating this wires chemistry, every weld engineer and metallurgist in North America would have been aware that this weld wire would be the last choice for welding structural components designed to with stand seismic loads.
THE NORTHRIDGE WELD REALITY:
BUILDING INSPECTIONS AFTER THE NORTHRIDGE EARTHQUAKE.
The Northridge Earthquake challenged the assumption that welded steel moment frame connections were automatically capable of extensive yielding without a loss of strength. SAC 1.2. Thousands of welded steel moment frame connections fractured during the earthquake. SAC 1.2. Once such a fracture formed, the beam-column connection experienced a significant loss of flexural rigidity in capacity. SAC 1.2. It fractured when its strength was needed most. An "astonishing" 99% of these failures in the beam-column connection occurred with "self-shielded flux-core" weld metal.(National Institute of Standards and Technology, NISTIR 5625 A Survey of Steel Moment-Resisting Frame Buildings Affected by the 1994 Northridge Earthquake).
Ed's Note: Only an "inexperienced engineer" or some one from Lincoln would be have been astonished at the results of this weld wire selection.
SAC Phase 1 Analytical Studies of Building Performance
Project Title: Lessons from Inspection, Evaluation, Repair and Construction of Welded Steel Moment Frames following the Northridge Earthquake
Subcontractors: William E. Gates, S.E.; Dames & Moore, Inc. Manual Morden, S.E.; Brandow & Johnston Associates Project Summary: Under the SAC Task 2, interviews were conducted to document the significant experiences of key participants involved in the discovery, inspection, evaluation, design, and construction repair of the steel moment resisting frame buildings. Structural engineers, testing and inspection agencies, contractors and building officials were selected as participants in the interview process. The interviews were designed to systematically gather, synthesize and analyze perishable data, such as impressions and unusual experiences that may have been encountered during the process, identify key issues or concerns, and lessons learned. These interviews produced several key findings, including:
[a] None of the engineers interviewed anticipated that a brittle rather than a ductile mode of failure would occur in welded steel moment frame (WSMF) construction prior to the Northridge earthquake experience.
Note from Ed. What does [a] above say about the weld process expertise of the engineers interviewed. And why would any intelligent person ask these engineers for an opinion on a subject they know very little about?.
In hindsight, a few of the engineers admitted that they were somewhat skeptical about the ability of the welded beam-column connection to fully develop a plastic hinge before some form of failure occurred in the highly stressed weld zone. However, these engineers felt they had no basis on which to reject the building code premise that ductile yielding of the connection could be achieved in an earthquake. All of the engineers interviewed, without exception, felt that their education or knowledge of metallurgy and the behavior of steel welding processes was lacking the necessary elements for them to appreciate the limitations for the materials they were working with.
Note from Ed::
Why would anyone want to read a report based on the opinion of engineers who admit they don't know what they are talking about.
If you are ignorant about a weld process or weld consumable, then, It's wise not to have an opinion on that process. And if you do need weld consumable information, the last place to ask for unbiased advice, is a representative of the company who makes the welding products.
As this web site indicates, the weld industry is full of individuals who have weld opinions yet have no weld process control expertise:
[b] The Northridge experience has reduced the engineers' confidence in the earthquake performance of WSMF's. from the standpoint of life safety, a well designed reinforced concrete shear wall building is now considered safer than a ductile WSMF constructed to the 1988 UBC (pre-Northridge) standards. About half the engineers consider the steel braced frame and ductile reinforced concrete frame to be safer than a WSMF and the other half consider it to be equally safe. The majority of the engineers still consider the WSMF to be safer than the following structural systems: non-ductile reinforced concrete moment frames with or without un-reinforced masonry infill, ordinary steel frames with un-reinforced masonry infill, URM's upgraded or not upgraded, concrete tilt-up (post-1976) and precast concrete without adequate connections.
Almost all of the failures, observed by those interviewed, were a brittle form of failure in the welded joint area between beam and column flanges. Only two or three joints in the thousands surveyed were observed to suffer significant plastic deformation. In some cases, plastic deformation occurred as a consequence of an initial brittle failure.
Note from Ed:
It's a pity the engineers lack confidence in a project in which the design of the component appears solid. These engineers need to get over the design discussion and rememnber this simple fact. According to NISTIR 5625 an astonishing" 99% of the application failures in the beam-column connections, occurred with "self-shielded flux-core" weld metal.
Engineers get your focus back on the available weld consumables that actually are designed to meet your weld requirements. I know the use of many common SAW consumables and gas shielded flux cored wires would without question pass any tests provided.Forget the smoke that Lincoln wants to surround this issue, engineers should keep their focus on the weld process. As reported by the National Institute of Standards and Technology, NISTIR 5625 Survey of Steel Moment-Resisting Frame Buildings Affected by the 1994 Northridge Earthquake).
Part of the failure issues here, is not just the failure of the welds and steel components during the earth quake, it's also the failure of the responsible engineers and managers to get the process training they require so they can make rational, correct weld decisions for the steel components they work with.
How can you have ductility or plastic deformation in welds in which;
[a] the weld consumables required no impact properties,
[b] the welds were made with a weld wire that contains larger than normal
amounts of aluminum and no discussion was had on the aluminum content and the aluminum multipass consequences,
[c] the self shield welds are not protected fully from the welding atmosphere and these wires are influenced greatly by the wire stick out variations and voltage adjustment,
[d] the high weld current and likely lack of inter-pass temperature controls may have had its influence on the HAZ grain size, especially when multi-pass welds were made,
[e] no one took a look at the porosity / slag content and influence on the weld failures,
[f] no one reported as to the consistency of weld fusion attained.
Article Continued: The degree of observed weld damage reported in interviews varied significantly from engineering office to engineering office. In general, when weld damage occurred, minor cracks, having a depth less than 1/4 inch, were found in approximately 40 to 60% of the damaged cases. Significant cracks with greater than 1/4 inch depth were found in 20 to 40% of the damaged cases, and severe cracks in 10 to 20% of the connections. The distribution of damage within buildings was reported to be relatively random in the low rise buildings with the greatest amount of damage in the first two stories. Damage in high rise buildings was found to be located in the upper one-half or two-thirds of the building. Directionality of the earthquake ground motion played a significant role in the damaged WSMF's. Those buildings located in the San Fernando Valley tended to have more damage in the north-south frames, while those located in West Los Angeles tended to have more damage in the east-west frames oriented parallel to Santa Monica Boulevard. The geographic distribution of damage, as reported, seemed to be related to the location of the building relative to the earthquake epicenter or center or energy release. Damaged buildings were located within a 20-mile radius of the epicenter. This included West Los Angeles, Santa Monica, Burbank, Santa Clarita Valley, and much of the San Fernando Valley. No damage was reported in Mid-Wilshire, Hollywood, or downtown Los Angeles.
There was little consensus among the engineers interviewed as to the major factors leading to the brittle failure in the welded moment connections. However, most now believe that the welded moment connection was a flawed design due to the high triaxial state of stress that limits yielding and plastic deformation and due to stress risers, such as the backup bar, and stress concentration factors, such as the interaction between the column web and beam flange in the weld zone. Furthermore, most of the engineers interviewed now believe that the qualification tests for the prescriptive connection failed to represent the evolving field conditions. Prior to the Northridge earthquake, the engineers were overly optimistic about the test results and tended to forget poor results. Other key factors named were the welding practices and materials (both base steel and weld metal) used in construction. The engineers were in general agreement that the rapid impulsive energy release from the Northridge earthquake may have been a key factor in the brittle failures observed. Few of the engineers felt that the amplitude of the ground motion or the high component of vertical ground thrust contributed significantly to the damage. All of the engineers interviewed agreed that standards and procedures for welding need to be revised and "tightened up" and that the design of the welded moment connection needs to be revised. There is also strong opinion on the part of some of the engineers interviewed that redundancy in the ductile steel moment frame needs to be increased.
Note from Ed: Perhaps it's these same engineers who need to tighten up and get a grip and better understanding of a fundametal process that is an integral part of their profession.
The testing laboratory personnel offered the following statements or opinions:
[a]. The AWS standards for welded connection acceptance are too lax for this type of joint and permit too much poor fusion and imperfections in the welds.
Ed Note: The AWS committee is typically made up many individuals who work for the companies who make the weld consumables
[b]. The certification criteria for welders is inadequate. For new work, welders should be required to qualify by welding a real joint in the same position as it will be constructed, including penetration welds with continuity through an access hole (i.e., the "rat hole" at the bottom beam flange to column flange). For repair work, the welders should also be required to perform the qualification welds with restricted access, similar to the conditions commonly encountered in the field.
Ed Note. Wow you would want to test welders on weld joints similar to the weld joints and conditions they work on every day, now that's a first.
[c] Many buildings investigated after the earthquake exhibited "atrocious" fit up, joint preparation and weld quality. This may be related to the degree of damage found in these buildings located furthest away from the epicenter, or in area of lower amplitude ground motion. In some cases, there was evidence of falsified or totally inadequate previous post-earthquake inspection (i.e., chalk marks on columns with arrows pointing up and marked "OK" where fireproofing had never been removed from the beam-to-column connection). Field inspection and testing procedures for weld damage varied from firm to firm. Most of the firms relied on engineering judgment to select the connections for inspection. Some firms used elastic dynamic analyses after the damage had been found to identify where to look further for potential damage. A few performed dynamic analyses, first, before going into the field to inspect the building. They assumed that this information provided a means of finding those connections that were more likely to be damaged. Visual and ultrasonic testing were the most commonly used methods for inspection. Inspection costs for typical commercial buildings ranged from $800 to $1,200 per connection. This cost did not include cases where asbestos had to be removed. In such instances, the cost could double or triple. a
Ed Note: Poor quality welds, poor quality weld joints, poor quality inspections. Does this not indicate a lack of ownership by the mangers or contractors? Someone could write a web site on this subject.
When fracture develops through the welds or flanges of the moment connections, related damage was found about half the time in the non-seismic (gravity) frame connections. The damage ranged from partially torn shear tabs to cases in which all of the bolts at both ends of the beam's gravity connections had failed, leaving the beam resting on the shear tab or supported from the floor slab above by the shear studs. The ratio of observed moment connection to gravity connection damage ranged from 3:2 to 20:1. There is one documented case of progressive crack propagation with time in an 11-story high rise building that was designed to 1.5 times UBC Zone 4 requirements. Over the period from July 1994 through December 1994, the cracks have propagated from the welds into the bases metal of the column or beam flanges. The engineers involved postulate that the crack propagation may be due to continuing relaxation of original residual stresses and readjustment of strains in the frames induced by the earthquake.
There is no common definition or repairable damage vs. damage that requires retrofit strengthening. The decision varies from engineering office to engineering office. There appears to be no real guidance from either the building department in the local community, the engineering profession, or the welding society on this matter. (Similar significant ramifications are implied in future earthquakes if ductile flange buckling and yielding develops in the moment resisting frames due to seismic overload. When should the connection be repaired to compensate for damaging plastic distortions or replaced to restore the structure its original elastic strength?) Guidelines and standards are needed by the engineers to identify the acceptable level and extent of damage before repair procedures are converted to retrofit strengthening.
Ed Note: Why look for guidance from people who have no expertise on the subject.
Engineers have proceeded with repair and retrofit strengthening based on judgment and common sense. They feel they are operating on their own, without specific guidelines as to scope of required repair and/or retrofit and without sufficient test data to substantiate the repair and/or retrofit schemes that they are using. The repair schemes typically consist of putting back a welded joint that more closely conforms to what the engineers thought they were specifying in the first place. Retrofit strengthening generally consists of adding plates or tees to the bottom and top flanges of the beam at the column joint to increase the connection capacity. There is little attempt to balance the design out by adding similar stiffness and strength to the undamaged connections of the WSMF. However, there is widespread concern is the engineering community that such an unbalance in stiffness and strength could result in less favorable performance in future earthquakes. Few owners are going beyond the simple repair process (i.e., putting the damaged connection back as it was before the Northridge earthquake). Only where FEMA or some other agency is picking up the cost of repair and retrofit are the owners requesting seismic upgrade. Repair costs for damaged connections in typical commercial buildings range from $3,000 to $20,000 per connection. The typical costs are in the $5,000 to $8,000 range. If asbestos has to be removed, the costs may increase by an additional $2,000 to $3,000 per connection. The owner's hidden costs associated with tenant expenses an lost rent may range from $0 to $45,000 per connection. Costs for retrofit strengthening may be comparable to those for repair in typical commercial construction. In residential and institutional construction, these costs may double or triple to $15,000 to $30,000 per connection for construction and $15,000 to $60,000 per connection for owner hidden costs if lost rental income is included. SAC Home SAC Steel Project/o Earthquake Engineering Research Center1301 South 46th Street. Richmond, CA 94804(510) 231-9477FAX: (510) 231-5664
A summary from Lincoln Lawyers web site: Lincoln supplied welding electrodes used to construct Special Moment Resisting Frames for buildings in the Los Angeles area. Certain of those buildings suffered damage in the 1994 Northridge earthquake, and Lincoln was sued by building owners proceeding on their own behalf and on behalf of a putative class of owners. Class certification was defeated and about 20 cases proceeded individually. The lead case was tried to a Los Angeles jury for over two months. Plaintiffs in that case originally sought over $800 million in damages under the Deceptive Trade Practices Act and at trial sought $100 million in damages on their fraud, products liability, and consumer protection claims. The jury returned a defense verdict, (a not guiltily verdict for Lincoln). In the only other case that went to trial, the jury returned factual findings on the identity of the welding electrode used in the building that led the court to grant summary judgment for Lincoln. The remaining cases were settled for nominal sums.
Ed Note: Remember the CA jury that found OJ not Guilty.
Note from Ed:
In 2005 now that the concrete dust and law suits have settled. The following is what Lincoln now states on it's web site for those intending to use the infamous and certainly not the cause of the collapsed buildings, the E70T-4 weld wire.
Recommendations in the Lincoln literature before the earth quake.
Use E70T-4 For structural fabrications where "No Seismic Requirements Exist".
Nov 2005: Ed's Conclusion on this great weld fiasco:
I first read this Greg Brouwer. 1999. LA Weekly News story on the web. This remarkable story is again an indication of the skewed legal and political system in the USA, and of course it also highlights some of the major problems with the competence of engineers and the welding industry.
This story has it all, from the end users and their lack of management weld ownership. An incredible naive believe in so called pre-qualified sales driven weld data. A gullible belief in the "AWS, don't hold me responsible weld guide lines and specifications".Lets not forget throughout this fiasco the universal lack of weld process expertise and too obvious overruling influence of salesmanship on engineering judgment. From Lincoln Electric we have the recommendation for a weld consumable that they should have hnown that it would not meet the weld mechanical properties of the intended application. Of course we also had the opinions of politicians and lawyers that could not recognize a weld consumable if they fell over it.
It's notable in this report, the lack of weld ownership and weld responsibility and fundamental process apathy shown by the managers and engineers who made the electrode wire selection. Why would any engineer rely to any extent on sales driven advice or AWS weld specifications that often provide incomplete or inaccurate weld data. As an AWS committee member who helped write the MIG gas mix specifications, I am well aware that most of the AWS specifications are influenced and tarnished by biased advice from weld spec committee members who just happen to work for a weld consumable manufacturer. There is a reason at the start of every weld specification you will see a paragraph saying something like this. "Use this welding information at your own risk".
While in contrast to all the data that found fault with the self shielded weld wires utilized, Lincoln maintained it's poor weld consumables were not the issue. I could be wrong, but it looks like they did not provide any metallurgical evidence to show that the self shielded consumables they recommended would actually meet the application mechanical requirements. After all if Lincoln was right, all it would have taken is a few hundred dollars to do weld mechanical tests that would have proved their E70T-4 met the seismic weld requirements. It seems to me that the weld qualification tests by Lincoln would have been a little cheaper than the millions they spent going around the fundamental issue. Of course they did not offer this as they knew the weld wires selected could not meet the weld quality requirements and mechanical properties required for the construction projects.
Lincoln must have many engineers and technicians that have been aware for decades of the self shielded consumable disadvantages especially from a weld quality / mechanical properties perspective. These same Lincoln personnel also knew that in contrast to the self shielded flux cored wires, the common automated SAW consumables and very common manual "gas shielded flux cored weld wires" supplied by Lincoln and by many other suppliers would have met the weld applications needs.
A notable point in this report was the complete lack of discussion on the superior gas shielded flux cored weld wire alternatives, products that need simple enclosures for weather protection, products that have been available for at least 30 years. With the gas shielded products, a few hours training is all that is required for anyone to make high deposition, sound quality welds that can meet any weld code requirements.
WHEN THE RIGHT PEOPLE DONT ACCEPT RESPONSIBILITY WE END UP WITH THE BLAME GAME
The following notes are from Ed:Why Lincoln?
Lincoln designed the self shielded flux cored wire to meet the AWS E70T-4 designation, a designation that clearly spelled out that this weld wire was intended fo applications that would not have to meet even minimum Impact properties. Why would a company that employed metallurgists and weld engineers therefore recommend the E70T- 4 wire ans similar products for structural weld loads that are subject to seismic activity?
Note: Weld strength, ductility and impact properties are fundamental properties for a seismic application and according to the AWS self shielded wire spec and ASME Section 11. SFA -5-20. The E70T- 4 self shielded flux cored wire. requires NO IMPACT STRENGTH REQUIREMENTS.[] In contrast one of the world's most common MIG steel wires is a E70S-6 , (nobody sells more of these wires than Lincoln). Now this wire would require impact weld properties of 20 ft/lb at - 20 F.The wires that should have been used, the E70T-1 gas shielded flux cored wires, and the all position gas shielded wires for the seismic application are of the shelf common products that are easy to use and sold by many wire manufactures. In contrast to the E70T- 4 SS wire, the E71T-1 wire provides the required weld strength and ductility, far superior weld control, superior weld penetration potential and and minimum impact properties of 20 ft/lb at - 0 F. Also available were gas shielded wires that could provide 20 ft/lb at - 40 F.
Why would Lincoln an organization that for decades employed Mr. Omer W. Blodgett, one of the world's leading experts on design and structural steel applications, recommend the worst possible electrode for these critical, structural applications?.
Why would Lincoln keep pushing ridiculous, over the top weld deposition rates that are rarely attained when weld quality, mechanical properties and weld heat input consequences are the key criteria for the welds?.Why would Lincoln want to sell a weld product that many of their own engineers knew could not meet the fundamental weld mechanical properties?
Note: As an ex-product and marketing manager for some of the world's largest weld product suppliers, I am well aware that it's a common sales ploy in the weld industry for a major weld consumable manufacturer to recommend one of their so called "unique, good or bad weld consumables" for a large account so that other weld consumable companies can not offer a lower cost or competitive alternative.
Lincoln is not alone in accountability for the weld issues. The lack of Weld Process Ownership shown by all those contractors and state agencies and engineers involved in the weld decisions indicated in this report, is a major issue today throughout all industrial nations and still continues in 2015 in CA.
Irrespective of common so called "qualified weld specifications" available today for weld joints, no company building a critical welding application should select a weld consumable for that application without;
[a] Managers: Take ownership and responsibility for the weld process and consumable selection for the application, ensure at minimum the following is carried out.
[b] Engineers: Select the consumables based on meeting the requirements of the application. Look at different consumables from different wire manufacturers. Qualify the desired weld process and consumables with appropriate test pieces that will be similar to the intended applications with the prime weld variables accounted for. Ensure the welds meet the actual weld joint and weld mechanical properties criteria. Use destructive and NDT weld tests for the weld joints.
Note: In the welding industry we do the above every day its called a Weld Qualification Procedure. (WQP).
[c] Engineers. After the WQP establish a "Weld Procedure (WP)" based on the WQP and the actual weld joints with the site conditions influence. Provide in the WP the preheat or weld heat interpass controls if necessary. Provide single pass weld size limits. Provide the exact welder technique required. Provide the required techniques for all positions. Provide root gap limits and resolutions for over/ under sized gaps.Provide minimum / maximum wire stick out recommendations along with a narrow wire feed / voltage range. For the welders and supervisors arrange both hands on skill training and process control training.[d] For the supplier of weld consumables. Be more than aware of the fundamental weld requirements for a critical life or death application. Offer a weld consumable that you know readily meets those requirements. If the weld consumable you offer does not consistently meet the requirements, then get off the pot and get out of the deal.
The WQP, WP NDT and Destructive Tests for the weld consumables would have required minimal costs. The simple, easy to do weld tests would have shown to any that were interested that the E70T-4 Self Shielded Weld consumables utilized would not have met the building designers fundamental design and weld specification criteria, a fact that any metallurgist or process application engineer who understands weld consumables would have known before the tests.
2007 Update. WHAT GOES AROUND COMES AROUND:
As reported by Lincoln Electric in the SEPT 2007 Welding Magazine from Penton.
"The AWS published in 2006 a supplement to it's standards on welding structures that are designed to resist seismic loading and Lincoln Electric is now offering training for unions and associations on these new requirements. The AWS developed the D1.8 Seismic Welding Supplement. The subcommittee that developed this standard was chaired by Duane Miller of Lincoln Electric. Lincoln reports that the earth quake drastically altered the industries understanding of how welded steel building behave during major earth quakes. (Note from Ed. No mention of the Lincoln weld wires influence). Lincoln also reports that "FEMA provided funds for studies to determine the cause of the unexpected damage and to provide recommendations". (Note from Ed. No mention of Lincoln's involvement with FEMA or the reasons that incompetant organization is involved in the buisness of welding).
Unfortunately if you spend 5 minutes on this site you will be aware of what I think about the influence of salesmanship and designers and engineers who are too often saturated in weld process BS and apathy. Last but not least. As an ultra hard working taxpayer, I can understand why lawyers will stoop to any level to earn a buck, however when I see the politicians and government agencies more concerned with the protection of a corporation rather than with the protection of its citizens it makes wonder how great this country really is.
Ed's Note: As you can see from this report. Building owners are confused, jury members will be confused, lawyers are confused but that works for them and last but not least too many apathetic engineers who lack the ability to research a simple two control weld process are confused.On a project of this scope, accountability for the structural failures in L.A is of course difficult to place on one persons shoulder yet one unnamed Lincoln person has a lot of involvement and a lot to say.
The process information presented on this subject would have bewildered any jury, as it appears to have bewildered many of the engineers involved.
I believe the LA engineers process confusion may have been a great plus for Lincoln and it's lawyers as the design / process confusion circumvents what should have been a simple "unbiased" examination of the E70T-4 weld capability and suitability for a seismic structural applications. The fact that Lincoln or was it the lobbyist for Lincoln that included FEMA, into the chaos and into the weld / design decision making process, was I believe a brilliant legal move.
Create confusion with technical facts. Bring in experts who are not experts or bring in experts that receive your remuneration. Always deny ownership, accountability and responsibility. Ensure you have a large wad of cash available for lobbyist, now that's a great and continuing lesson for other large global corporations who want to avoid large liability consequences when they make mistakes that cost life.
Its interesting that Lincoln choose Jones Day Reavis & Pogue, the firm that represented R.J. Reynolds in the Great American Tobacco Wars.
It makes a strong statement.
Sept 207: Foot Note: The AWS Published in 2006 a supplement to its Standard on Welding Structures Designed to Resist Seismic Loading. This AWS D1.8 supplement was written by a committee that was chaired by a Mr. Duane Miller of Lincoln Electric. Mr. Miller is presenting a work shop on the new seismic standards to the American Institute of Steel Construction AISC at a conference in April in New Orleans. I would be surprised at this work shop if Mr. Miller lays any responsilty for the weld failures on Lincoln's weld consumables. I also find it ironic that this work shop is to be held in New Orleans, the location of FEMA'S greatest incompetence.Note from Ed. Maybe I will change the name of my new welding movie to
"The Fox is finally in the hen house"
From Castro Associates Law Office:
HAS THE STATUTE OF LIMITATIONS EXPIRED FORSTEEL MOMENT FRAME STRUCTURES?
The Northridge Earthquake struck Los Angeles on January 17, 1994. Owners of steel moment frame buildings were shocked to learn, after the earthquake, that moment frame connections, critical for seismic resistance, had suffered brittle fracture failures. On January 16, 1997, Pillsbury, Madison & Sutro filed a class action lawsuit naming all steel frame owners as members of the “putative class,” and presumably “tolling” the statute of limitations. On February 4, 1998, the class action allegations in the Pacific Design Center et.al vs. The Lincoln Electric Company, (LASC number BC 164 229), were dismissed. No notice period was provided by the court in entering the dismissal. Are owners of steel frame buildings who did not file their lawsuits during the pendency of the class action or before the dismissal now barred by the three year statute of limitations CCP §338(b)?
Building Inspections After the Northridge Earthquake
The Northridge Earthquake challenged the assumption that welded steel moment frame connections were automatically capable of extensive yielding without a loss of strength. SAC 1.2. Thousands of welded steel moment frame connections fractured during the earthquake. SAC 1.2. Once such a fracture formed, the beam-column connection experienced a significant loss of flexural rigidity in capacity. SAC 1.2. It fractured when its strength was needed most.
An astonishing 99% of these failures in the beam-column connection occurred with “self-shielded flux-core” weld metal. (National Institute of Standards and Technology, NISTIR 5625 A Survey of Steel Moment-Resisting Frame Buildings Affected by the 1994 Northridge Earthquake).
On March 1, 1995, the City of Los Angeles adopted a mandatory ordinance that required the inspection and repair of buildings with moment frame connections in designated earthquake damaged areas. Los Angeles Cal. Mun. Code §91.8908(a). In 1996, the City of Los Angeles banned the further use of flux cored weld metal, including E70T-4 weld metal, because it could not meet required “toughness” standards.
Technical Studies After the Northridge Earthquake Found that Brittle Weld Metal Was a Substantial Factor For the Failures.
Industry studies have confirmed that self-shielded flux-core electrodes were a substantial factor of brittle weld failures during the Northridge Earthquake.
The Center for Advanced Technology for Large Structural Systems at Lehigh University published findings in 1996, concluding that the welds deposited with E70T-4 electrodes (self shielded flux-cored arc welding electrodes) had very low fracture resistance to moderate earthquakes and were likely candidates for brittle fracture failure. Id. at 31. [1]
The Lehigh study found that brittle weld fractures developed in installations that used E70T-4 welding electrodes with backup bars. The fracture origins were identified at the weld root adjacent to the notch introduced by the backup bar at a location with inadequate root penetration. Kaufmann at 33. In contrast, when a ductile weld metal was used to fabricate a joint (such as E7018 stick electrode), no weld metal cracking occurred and the ultimate strength of the beam plate was developed, that is, it became a moment frame. Id.36.
Dynamic testing showed a much improved performance in strength and ductility (toughness) when the E7018 stick electrode was used. The Lehigh testing concluded that acceptable connection performance is obtainable by using a higher toughness weld metal, such as E7018, with the removal of backup bars. Id. at 39.
Manufacturer’s Liability
Statute of Limitations Defense
Will dismissal of the class action lawsuit cause the loss of viable claims against the manufacturers of the E70T-4 weld materials? Generally, the statute of limitations for discovered injury to property is three years. CCP §338(b).
The three year statute does not begin to run until the plaintiff is aware of the injury and its negligent cause. Jolly v. Eli Lilly & Co. (1988) 44 Cal.3d 1103, 1110; 245 Cal.Rptr. 658. The fact that the earthquake caused damage to a steel frame building may not start the running of the statute of limitations absent evidence that the owner was aware of the negligent cause of the injury.
Since the City of Los Angeles did not require inspections until after the adoption of the ordinance on March 1, 1995, the accrual date for the statute of limitations will likely commence from the date the owners received inspection reports from expert consultants. Simply stated, the commencement of the three year statute of limitations will vary from building to building and ultimately will be determined on a case by case basis.
Finally, the filing of the class action tolled the statute of limitations from the date of the filing of the lawsuit to the date of dismissal of the class allegations (Pacific Design Center et.al vs. The Lincoln Electric Company). Whether this tolling period can be used depends of the facts of each case.
Thus, it may not be too late for steel frame owners to file their steel frame actions.
Lehigh concurred with published studies by the University of Texas at Austin and the University of Southern California which showed brittle fracture failures in laboratory configurations for “self shielded flux-core” (E70T-4) weld metal connections. Following the earthquake, the City of Los Angeles issued interdepartmental memos calling for weld metal toughness of 20 foot pounds at 0 degrees Fahrenheit. (July 16, 1996, City of Los Angeles Interdepartmental Correspondence re Requirements For The Repair of Welded Steel Frame Connections In Existing Buildings.)
The self shielded weld Consumables recommended by Lincoln and have for more than a decade been costing the Auto / Truck Industries Millions of dollars every year.
California Northridge Earthquake or Chrysler Robot Welds.
Ed has provided much more comprehensive weld info on the self shielded weld wires. Its in Flux Cored Section.
