Bridge and Road Durability Working Group - Email
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Dear Folks,
We are having some difficulty in getting lead people in place for this
working group so I have decided to call for a conference call to decide
what it is we can do with bridge and pavement between now and April to
answer the question Congress wants answered on bridge safety and weight
impacts.
First, I think we need to determine if all the bridges on the interstate
system will support an operational rating of 100,000 lb trucks. Here is
the information we have been providing in our briefings?
Of 197 total bridges on Maine's Interstate System, 36 are
functionally obsolete, and 6 are structurally deficient. These bridges
should be examined prior to implementing any program that increases
vehicle weight and eliminates the bridge formula. (These numbers do not
include 83 bridges on the Interstate System maintained by the Maine
Turnpike Authority)
Of 313 total bridges on Vermont's Interstate System, 95 are
functionally obsolete, and 22 are structurally deficient. These bridges
should be examined prior to implementing any program that increases
vehicle weight and eliminates the bridge formula.
Are the 28 structurally deficient bridges going to be able to handle the
100,000 pound trucks? We need to answer that question. Can we do that
by next week or is there more analysis that needs to be done on these
bridges. If there is more analysis that needs to be done who is going
to do it and is there an out-of-pocket cost for that? I need to know if
we are going to need to hire someone for that activity. From what I
have been told by our bridge technology office, a bridge is structurally
deficient when any major bridge element receives an inspection rating of
poor or lower, is closed, receives a low structural evaluation rating
based on a load rating and level of service, or has limited waterway
access.
In our January 14th meeting we had general agreement that we were going
to look at bridges in the following order: structurally deficient,
average condition, and new bridge. To get off dead center we need to
have folks step up to the plate who are going to do that analysis or we
need to find contractors that will. Need your thoughts on this.
Regarding pavements, Tom Yu, here in our pavement technology office,
said he can do a direct side-by-side comparison of the relative damage.
For the impact on pavement design he would run the MEPDG using the axle
load distributions from the state routes (where the 100-kip trucks have
been allowed) and interstate routes (data collected prior to the
introduction of the 100-kip trucks). Based upon these analyses results
he can calculate the additional pavement costs attributable to the
100-kip trucks. To do his analyses he will need several years of axle
load data which I believe the Truck Volumes Working Group is gathering.
I can meet next Tuesday or Thursday PM. Please let me know if you are
available and we will use the same call-in number for our other
meetings.
David Jones, you are welcome to attend this if you like since the data
your working group is gathering will help here.
Michael P. Onder
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