Saturday, March 22, 2008

Risk Of Failing U.S. Highway System: Deadly To Drivers

According to the American Society Of Civil Engineers’ (ASCE) Report Card for America’s Infrastructure, an estimated $1.6 trillion is required over a five-year period to fix our failing infrastructure to bring them to a good condition. Of this, $210.3 billion a year is required just to keep the surface transportation system working[i].

Here is an excerpt of their most recent report card as of 2005: (2008 update from ASCE)

What Is The Risk?
New York Times reported today that another Minnesota bridge was closed due to bent bridge joint reinforcements (‘gusset’ plates), a problem similar to the Minneapolis I-35 (westbound) bridge that collapsed on August 1, 2007. In the I-35 (westbound) bridge collapse, 13 people died and 45 people were injured. Aside from the human and litigation costs, which are still not quantified, Minnesota Department of Transportation estimates the lost revenue of detouring nearly 140,000 vehicles that used to go over the I-35W bridge is approximately $400,000 a day. Moreover, it estimates impact to local economy to total $60 million. Based on the estimated completion date of the bridge of December 24, 2008, direct and indirect lost revenues totals approximately $264.4 million.

Adding in the cost of building the bridge of approximately $234 million to $264.4 million in lost revenue, we arrive at a total cost of lost revenue and construction of approximately $498.4 million. One can figure that the litigation cost associated with the bridge collapse to be several multiples of this figure.

What Is The Cost of Mitigating The Risk?
According to the American Society Of Civil Engineers’ (ASCE) 2005 report card, updated to 2008, estimated cost to maintain our surface transportation infrastructure is $155.5 billion annually. Currently, only about $60 billion is allocated, leaving $95.5 billion gap.

Even to a non-risk manager, this would be an obvious gap that requires closure. If one believes the American Society Of Civil Engineers’ (ASCE) cost to repair / maintain our transportation systems (air, road, bridge, rail, transit, and water), then the annual cost is approximately $210.3 billion. ($150.3 billion, if one nets out the $60 billion currently spent.) ASCE also estimates that our failing transportation infrastructure is costing Americans approximately $145.2 billion in additional travel time, operating cost and repairs, about $722 per motorist a year.[ii]

Fact Tidbit: We’ve spent more than $510 billion (or $1,700 for every American) in the Iraq War and are still spending $200 million a day. Economists are projecting that by the time we add up all of the cost of the war, including veteran health care and benefits, the total cost would exceed $1 trillion and perhaps reach $2 trillion. Perhaps this money could have been allocated to our transportation infrastructure, making this a better nation.

13 dead and 45 people injured. 140,000 vehicles adversely affected daily, resulting in $400,000 per day in lost revenue to the local economy from an I-35W Bridge collapse. All because the gusset plates in the I-35W Bridge were assumed to be sufficient and therefore not inspected. If they were inspected as part of a normal inspection process, they would have found what the NTSB (National Transportation Safety Board) declared in their January 2008 preliminary report[iii]:

“The investigation discovered that the original design process led to a serious error in sizing of some of the gusset plates in the main trusses. …results indicate that some of the gusset plates were undersized and did not provide the margin of safety expected in a properly designed bridge. These undersized gusset plates were found at 8 (of the 112) nodes on the main trusses of the bridge… These gusset plates were roughly half the thickness required."

In looking at the actual engineering calculation of the gusset sizing[iv], it is clearly obvious that the failed gusset plates in sections U10 and L11 were only 1/2 inch thick while gusset plates on U6 and L5, the mirror opposite of the failed gusset plates, were 1 inch thick and 5/8 inch thick, respectively. So, for a lack of half-inch thickness at each of these two support joints (U10 and L11), the bridge collapsed.

As for the NTSB’s preliminary comment that asserts:

“Bridge inspections would also not have identified the error in the design of the gusset plates.” And
“The error in the design of the gusset plates would not have been identified by routine load rating calculations because gusset plate stresses are not normally part of these calculations.”

I can’t buy that. Click here to see an actual picture of the I-35W Bridge gusset, taken in 2005. Now, tell me that a bridge engineer could not have inspected the gussets and figured out that there might have been a potential problem.

I hope the I-35W bridge tragedy would be the wake-up call for the Federal Government to work closely with the States to ensure that a similar tragedy is not repeated.

Ed Kim
Practical Risk Manager
[i] 2005 Report Card For America’s Infrastructure, updated to 2008

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