After inspecting more than a dozen Wisconsin bridges in
response to a collapse in Minnesota last August, state officials and experts
will scrutinize a total of 127 bridges? design in the upcoming weeks.

The additional bridges will be examined next month, as a
group led by the Wisconsin Department of Transportation and the University of
Wisconsin will hold a workshop to analyze the so-called ?truss? bridges, all of
which have a design structure similar to the one that collapsed.

The decision to evaluate these particular bridges stems from
new information about a critical safety element they share. The strength of the
gusset plates (the one-half- to one-inch-thick load-bearing devices that are
one of the most important structural elements of truss bridges) are being
evaluated.

Initially, only the 14 Wisconsin bridges with the
?deck-truss? design most similar to the collapsed I-35 bridge in Minneapolis
were inspected, but the state now plans to implement a design check to all 127
truss bridges in Wisconsin. Beth Cannestra, director of DOT?s Bureau of
Structures, said the design checks are mainly a precautionary measure.

?We don?t anticipate changing the gusset plates,? Cannestra
said, adding these design checks, which constitute a systematic appraisal of
how the bridge is built, will be limited to high-risk bridges. ?We are keeping
the design check within fracture-critical bridges, consistent with [National
Transportation Safety Board] recommendations.?

Cannestra also emphasized the difference between inspections
and design check. ?An inspection is a physical visit to a site in which
engineers analyze the integrity of the structure, whereas design checks take
place away from the actual site of the structure and are intended to evaluate
and analyze the design of the structure,? she said.

The design check will take place during a workshop held next
month. This workshop will include the Wisconsin DOT and staff from UW-Madison,
UW-Milwaukee and Marquette University.

Gary Whited, program manager for the Construction and
Materials Support Center at UW-Madison, said in the second workshop, the group
will use the data taken from the first set of bridges inspected to apply to the
rest of the truss bridges.

Noting the I-35 collapse was in many ways unique, Whited
also said these precautions were little cause for alarm.

?The I-35 bridge was built with only half-inch gusset plates
and had been structurally modified over the years. These factors contributed to
its collapse,? Whited added.
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UW professor Jeffrey Russell, chair of the civil and
environmental engineering department, said the evaluation is little cause for
concern.

?Wisconsin tends to build bridges that are built with
tried-and-true approaches rather than riskier techniques that have not been
implemented on a full, real-life scale,? Russell said. ?We may build bridges
even safer than they need to be.””

According to DOT, the closest truss bridge to UW is on East
Dyerson Road, near Stoughton over the Yahara River. Another similar bridge runs
over the Rock River on U.S. Highway 51 in Rock County.