Posted by Nathan Kahl
at 12:03 PM on November 24, 2009
From time to time this column will highlight ethics issues and activities involving NAE members. To suggest a topic, email Nathan Kahl @ nkahl@nae.edu.
Engineers learn from past mistakes and failures. It might even be postulated that engineers and the engineering profession have a duty or responsibility to do so, although this duty is not always spelled out in engineering codes of ethics. Professional ethics develops from discussions and deliberations among members of a profession. Changes in codes of ethics reflect those continuing exchanges. Sometimes deciding where to “draw the line” needs legislative action – or action on the part of the profession; this can help engineers know where to stand on a particular issue.
The subject of this entry in the CEES ethics column is the collapse of the Koror-Babelthaup Bridge on the island of Palau and the efforts of an NAE member to investigate the records associated with the collapse and to raise the issue of whether such records should be made public .
Collapse of the Koror-Babelthaup Bridge on Palau
Palau, one of the smallest nations in the world, is situated 500 miles east of the Philippines and 2,000 miles south of Japan. The Koror-Babelthaup Bridge (pictured; hereafter “the Palau Bridge”) was built in 1977 to link the country’s two major islands, Koror and Babelthaup. The main span, 240 meters long, was the longest concrete girder bridge in the world at the time of its construction. By 1990, a sag, or “deflection,” had developed in the middle of the bridge, and although two engineering firms declared the bridge safe, a decision was made to attempt to correct the deflection, which had become both visually obvious and discomfiting to drivers.
The reinforcement design consisted of four elements:
- The non-weight-bearing central hinge joint was replaced with concrete, making the bridge a continuous structure from statically determinate cantilevers.
- Eight external pre-stressing cables were added.
- Eight flat-jacks between the top slabs were added to increase pre-stress.
- The bridge was resurfaced to create the appearance that there was no deflection.
Three months after completion of the refurbishment, on September 26, 1996, under virtually no traffic load and in pleasant weather conditions, the bridge collapsed, killing two people.
The cause of the collapse was not immediately apparent to public inspection and investigation; it was not until 2008 – 12 years after the collapse – that data from the collapse investigation was made available. To reach a no-fault settlement, without holding a trial, the agreement may well have required that all of the records be sealed.
Learning from failure
NAE member Zdenek Bazant, professor of civil and environmental engineering at Northwestern University, had become interested in writing a report on the collapse of the Palau Bridge not long after it occurred, but he found that no technical data would be released by the parties involved in the collapse investigation. Dr. Bazant believed that it was essential to write a report on the collapse, urging that “a thorough analysis and discussion of the collapse would most likely advance the understanding of the roles of creep and shrinkage, diffusion and hygrothermal effects, fracture mechanics and size effect in very large concrete structures.”
The engineering community often considers the study of such a major collapse as an opportunity to correct and improve on future design, as Theodore Galambos, NAE member and Emeritus Professor of Civil Engineering at the University of Minnesota, noted in an item he wrote for The Bridge in 2008. For instance, after the collapse of the Point Pleasant Bridge in Ohio in 1967, Galambos wrote, “The design, construction, inspection, and maintenance of bridges changed radically. Biannual inspections and material fracture toughness requirements were mandated. The change of most interest was the requirement that a bridge be robust.”
As a point of comparison, Bazant argued that engineering advancement would have been significantly retarded had the information from the Tacoma Narrows Bridge collapse of 1940 not been made available. When an investigation reveals a major technical or scientific problem that was not understood at the time, the concealment of records is problematic. The vast majority of disasters, he noted, are attributable to human error, and revealing information about these errors should be of less concern to the engineering community than the technical advances they engender.
From the little information he had gathered about the Palau Bridge, Bazant was convinced that an investigation would reveal issues of significant technical importance. However, in his efforts to obtain the records of the bridge collapse, Bazant says he found that the records were sealed in perpetuity, a situation that he found disconcerting. During litigation, many accident investigations are conducted through the courts, with the final agreement often including a clause stating that extensive investigations conducted by either, or both sides, may not be released publicly.
This is in stark contrast with accident investigations in the aeronautics industry, for example, where neither airplane builders nor airlines can be shielded by confidentiality clauses. Open, public investigations are undertaken by the National Transportation Safety Board, which was created with enabling legislation that included appropriated funds for that purpose. In addition, international laws require investigations into air accidents, and the voluntary sharing of near-accident information is part of the culture. The same is not true for structural collapses.
The situation that Bazant confronted accentuates a tension between legal procedures and ethical responsibilities as engineers perceive them. Engineers may ask themselves: To what extent does the inability of the profession to examine and learn from the details surrounding a structural collapse create an ethical responsibility for engineers not to simply protest such sealing of documents but also to refuse to consent to be party to such secrecy? Should engineering societies advocate for public release of technical information relevant to structural failures? Can there be reconciliation between the rights of private entities to maintain control of their records with the need for disclosure for the benefit of avoiding accidents in the future?
On November 6, 2007 Bazant introduced a resolution to the Structural Engineers World Congress (SEWC) – subsequently passed – stating:
- The structural engineers (at the congress) deplore the fact the technical data on the collapse of various large structures, including the Koror-Babelthaup Bridge in Palau have been sealed as a result of legal litigation.
- They believe the release of these data would likely lead to progress in structural engineering and possibly prevent further collapse of large concrete structures.
- In the name of engineering ethics, they call for the immediate release of all such data.
Shortly after the resolution passed – in 2008, as noted above – Bazant was granted access to the Palau Bridge records. Some have claimed that they were released at this time because the parties involved considered the legal issues settled and so had no problem with releasing technical data. Whether the data release was a direct result of the SEWC resolution cannot be said for sure, but Bazant strongly feels the timing was no coincidence.
Bazant not only made assiduous efforts to get the resolution passed, but he also encouraged NAE to take an official position on the issue of non-disclosure of technical data after major disasters. He believes that such non-disclosure is against engineering ethics and has raised the subject in the NAE civil engineering section of the NAE. In response, this section has established a study group, headed by Ross Corotis, professor in the Department of Civil, Environmental, and Architectural Engineering at the University of Colorado-Boulder, to investigate the need for accessibility to the results of failure investigations in the United States
As this column is being published, a draft statement written by a subgroup of the study group is being circulated for comment among study group members. In terms of the final content of the statement, Corotis said, “It is not clear what the final recommendation of the group will be, but unless there are concomitant changes to the U.S. legal situation, such a blanket statement (that an engineer not disclosing data is acting unethically) is likely to be considered too overarching.” The argument has been made, in fact, that the implications of such a statement would be harmful to NAE members – and to engineers in general - who carry out investigations.
Reconciling conflicting values
Gary Klein, a senior principal at Wiss, Janney, Elstner Associates – a firm specializing in investigations of structural collapses – noted that engineers have an obligation to protect the interests of their clients, who may object to the release of collapse investigation files due to concerns over ongoing or future litigation, adverse publicity, and the privacy rights of involved parties. Bazant suggests that engineers should seek to avoid investigative endeavors that would bind them to non-disclosure agreements when the sharing of the data would result in significant new learning for the profession. He even suggests that forensic engineering firms have a bias to favor non-disclosure of information, as “the legal resolution is based on their judgment and if this judgment is shown in subsequent public scrutiny to be technically incorrect, they lose reputation and a revision of the court settlement may be provoked.”
But in many instances, according to numerous engineers and NAE members consulted for this piece, parties to such lawsuits do not object to experts publishing papers or giving presentations on the case if the purpose is to help others learn from mistakes made and if the lawsuits have been settled. Indeed, in September of 2008 Bazant and colleagues presented a paper at the International Conference on Creep and Shrinkage of Concrete on the Palau Bridge collapse, a paper which was only written after the attorney general of Palau granted permission for the investigation records to be examined, as noted above. Bazant says that the paper will result in major changes in the field…but that it should have been written ten years sooner.
Can there be a compromise between the two positions, one insisting on the strictest ethical standards and another recognizing the legal realities and investigative duties of an engineer to his employer? The conflicting and seemingly near-irreconcilable positions over an issue that some would argue is potentially a matter of life and death is indicative of the ethical challenges facing engineers in their day-to-day lives. As in the medical profession, perhaps, these questions should not to be put on the shoulders of practitioners in the field but should be addressed by committees of experts in professional societies who can provide guideposts. As former NAE president Bill Wulf has said, “As we engineer more things with ever greater consequences, we ought to be engaged in just such macro ethical discussions – discussions that cannot put the onus on the individual.”
A fundamental precept of most engineering codes of ethics is that engineers should hold paramount the health and safety and welfare of the public. In accordance with this, engineers and their societies need to promote public accessibility of important technical information on engineering failures.
John Hanson, NAE member and Distinguished Professor Emeritus, Department of Civil Engineering, North Carolina State University, indicated this might be the most reasonable avenue for the study group to take. He suggested, “Perhaps NAE could encourage ways and means to support investigators in carrying out their work with the thoroughness that would support its eventual release for professional use, as well as to support them in seeking approval from their clients to release the information. I believe the best way to release information on failures is through the preparation of technical papers that are peer reviewed and discussed.”
Regardless of the action NAE may take on the issue, the efforts of Zdenek Bazant, through SEWC and now with his colleagues at NAE, have started a discussion of the issue by the right people. His passion for this topic, and the paper he wrote on the collapse of the Palau Bridge, testify not only to his energy and commitment, but also to the difficult challenges ethical decisions present every day for practicing engineers.
Further reading
This list, while not fully inclusive of materials written regarding the bridge collapse, provides further details regarding the bridge collapse.
The paper that Bazant and colleagues wrote after examining the released records.
A paper by Richard Scantlebury and Chris Burgoyne of Cambridge, written prior to the release of records and from publicly available materials, "Why did the Palau Bridge Collapse" argues that the repair to the bridge was not the the cause of the failure, as was widely assumed, but that a lack of robustness in the original design meant that the structure had always been vulnerable to accidental damage, which eventually occurred as part of the resurfacing works.
Burgoyne and Scantlebury followed this paper with Lessons Learned from the Bridge Collapse in Palau, which argues, "the construction industry should not shelter behind confidentiality clauses but, like the aircraft industry, publish its mistakes so lessons can be learned."
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