"The inadequate flow of information within MN/DOT was related to the loss of engineering personnel," LePatner explains. "Placing the primary blame for a failure of this magnitude on engineers was an attack on the profession as a whole. Yet the silence of the profession has been deafening. The American Society of Civil Engineers, the largest professional engineering association in the country, has marshaled no protests and has conducted no investigations of its own to challenge this indictment of individual engineers who are no longer around to defend themselves."
The NTSB report does not mention the bridge's rusted bearings. The June 2006 MN/DOT inspection noted surface rust corrosion and pack rust connected with the unsound condition of 15 percent of the paint; numerous problems with the main truss members, including poor weld details, section loss, and flaking rust; and a variety of problems with the floor beam trusses, stringers, truss bearing assemblies, and other components.
"While the NTSB findings on the cause of the collapse made no reference to the condition of the bridge bearings, frozen by years of rust, they may have played a contributory role in the collapse," notes LePatner. "MN/DOT's inspection reports acknowledged that the I-35W Bridge's members were bent or misaligned, and that critical bearings had been rusted and frozen in place, preventing movement. All of these signs of deterioration should have required close scrutiny, but that never happened. The NTSB ignored the significance of these reports."
As part of his investigation, conducted with interviews of bridge engineering experts across the country, LePatner was able to identify the likely cause of the I-35W Bridge collapse as being triggered by a weakness in one of the bottom chords of the design trusses, a finding that appears to have separately been identified by the structural engineering experts retained by the attorneys for many of the plaintiffs in the civil action against the bridge's contractors and engineers.
"What is most important to note about the role of the NTSB is that it failed to serve as a clearinghouse to alert all other state bridge operators about the lessons that should have been learned from the collapse of the I-35W Bridge," notes LePatner. "As I present in Too Big to Fall, there are still 7,980 bridges in the nation that are both structurally deficient and fracture-critical, each of which is in danger of suffering the same fate as the I-35W Bridge.
"To have failed to identify the true causes of the collapse of the I-35W Bridge is one notable failure of this governmental agency. But to have ignored the lessons that should be alerting the other forty-nine states that their citizens, too, are in jeopardy of suffering the same tragic fate is inexcusable.
"The NTSB missed a critical opportunity to use the lessons that should have been learned from Minneapolis's tragedy to ensure that similar conditions at bridges all across the nation do not lead to more disasters," he concludes. "The risks of continuing to ignore our ill-maintained national in¬frastructure are almost unimaginable. This discussion must turn into a dialogue at every level of government and policymaking. Our future national security and our ability to retain our global leadership status are at stake."
About the Author:
Barry B. LePatner is the author of Too Big to Fall: America's Failing Infrastructure and the Way Forward and Broken Buildings, Busted Budgets: How to Fix America's Trillion-Dollar Construction Industry (University of Chicago Press, 2007), and the coauthor of Structural and Foundation Failures. He is founder of the New York City-based law firm LePatner & Associates LLP. For three decades, he has been prominent as an advisor on business and legal issues affecting the real estate, design, and construction industries. He is recognized as one of the nation's leading advisors to corporate and institutional clients, real estate owners, and design professionals.