Bridge Construction
Jesse Murray
English 202C
Dr. Peter Froehlich
21 October 2009
Bridges are used by thousands of people every day who are simply trying to get from
point A to point B in their daily lives. Bridges are most often used to span rivers, massive gaps,
or dangerous terrain. There are many factors that are to be considered before building a bridge.
Some of these factors include the distance that the bridge will span, and whether or not the
bridge will be constructed over a river, bay, or canyon. Also, civil engineers must take into
consideration the traffic flow that will happen on the bridge and the amount of load the bridge
will have to carry (Microsoft Corporation). Due to the recent situation in failing infrastructure
nationwide, bridges past a structural point of repair should be replaced with new ‘Smart Bridge’
technology.
The bridge that is planned to be constructed will be modeled after the St. Anthony Falls
Bridge in Minneapolis which contains many of the ‘smart bridge’ technology’s that will be used
in our bridge. The bridge is packed with sensors and other electronics that constantly monitor
the concrete for any weaknesses or structural damage. In a research article by Steve Hamm,
Steve explains that the sensors that were installed in the Minneapolis Bridge do more than keep
track of maintenance needs. They also monitor weather conditions and automatically trigger an
anti-icing system to prevent the roadway from freezing over during the winter. The bridge’s
cement contains nanotechnology in it that creates a photo-catalytic reaction (upon reaction with
UV lights) that cleans pollution out of the air. Hamm goes on to quote the chief civil engineer
who oversaw the construction of the bridge in Minneapolis, Jon Chiglo when Jon said, “The
technology is about speed, it’s about quality, and it’s about efficiency” (Hamm 2009).
The bridge collapse in Minneapolis led many to question infrastructure safety. This in
return led to officials being alerted to the fact that the national infrastructure is not fail safe, and
that reports of damage and stress need to be taken seriously. In Maya Grinber’s article she
discusses bridge criteria which include classification categories such as “Structurally Deficient,”
“Functionally Obsolete,” and other more typical categories such as “Good”, “Fair”, and “Very
Good”. The bridge in Minneapolis was considered structurally deficient, but structurally
deficient status does not mean there is immediate danger. It usually means that the bridge will
have infrastructure renovations in the next 10 to 15 years. Maya goes on the explain that within
a week of the Minneapolis collapse that investigators found what they considered to be a design
flaw in the steel parts that connect girders. Finding out what factors truly caused the collapse in
the bridge (like a design flaw) would lead to a blanket overhaul of similar bridge designs. The
Minneapolis Bridge was a truss bridge that contained no underwater pylons which essential
means that the entire structural support is focused on the two ends of the bridge (Grinberg 2007).
Maya’s research coincides with Monica Davey and Mathew Wald’s research in that they
believed that a design flaw in the bridge’s gusset plates may have played a pivoting role in the
Minneapolis bridge collapse. A bridge’s gusset plates are the steel connectors used to hold
together the girders on the truss of a bridge. It is hypothesized that those who designed the
Minneapolis Bridge in 1964 may have used metal parts that were too weak, and may have even
miscalculated the loads that would be applied on the bridge. Davey and Wald go on to explain
that Federal authorities believe that one extra added stress on the gusset plates may have been the
weight of construction equipment and nearly 100 tons of gravel that was present on the bridge at
the time of collapse (Davey et al. 2007).
In the long run due to rising insurance issues and the high percentage of necessary
inspections and “band-aid” type repairs; the increased costs that come with completely
rebuilding a bridge are financially more justified. In years to come bridge maintenance and
upkeep should continue to be researched so that one day commuters traveling across bridges will
not have to fear of a possible bridge collapse. Furthermore, in the future, research and
advancement in the construction of making bridges more safe and reliable should always have
the highest priority so that another Minneapolis disaster never happens again.
References
Davey, Monica, Matthew L. Wald. “Potential Flaw Found in Design of Fallen Bridge." New York
Times (Aug 9, 2007): A.1. Proquest.
Grinberg, Maya. "Minnesota Tragedy Sparks Review." Risk Management 10, no. 54 (Oct 2007):
12. Proquest.
Hamm, Steve. "Brains In The Concrete And Steel." Business Week 4121, (Mar 2, 2009): 42. ‘
Proquest.
Microsoft Corporation, "MSN Encarta." Bridge (structure). Available from ‘
http://encarta.msn.com/text_761561057_22/Bridge_(structure).html. Internet; accessed ‘
20 October 2009.