Every
year the FIU-ASCE Student Chapter participates in the Regional
Competitions. One of the most important competitions is the
The
Team:
I
want to Specially thank:
Chris
Rego, Juliana Vazquez, Brensa
Solis, Randall Blanchette,
and the Co-Captains Christian Diaz
and Enmanuel Espinal
for all their collaboration during the fabrication of the Bridge. Also to
the ASCE members that spend
at least a little time helping with something, and Professor Edgar Polo
for his support.
I
also want to thank our
Kaushik
Dutta, S & F Engineers,
Inc.
Dade
Steel Sales Corp.
R
& D General Welding Services
Dan
Becker,
and
The Students fro
General
Idea:
The
competition rules this time requires the bridge to be assembled in the
shortest time possible and must support a lateral load and 2 different
vertical loads that will be located at random on the bridge.
Top View
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If you would like to see the official rule click on: Steel Bridge Rules 2006
Problems
during development of this project:
When
we started working of this project we had two things in mind: that we were
going to have enough money for the material and help during the
fabrication. The design of the bridge was not easy, many conditions had to
be fulfilled and our first error was to design the bridge thinking that we
could figure the assembly of it later.
Unfortunately
by the time we had to start fabricating the bridge we had a very low
budget. More than half of the materials was donated and all the manual
labor had to be done by our selves. This was the first time we faced a
project so important with such limited resources. Since we had to
fabricate the bridge ourselves there were many imperfections that made the
bridge even more difficult to assemble.
Even
of all the difficulties and errors, I am very happy that we could
fabricate such a difficult bridge. We assembled it a couple of times but
we couldn't figure the way to put it together the way the rules required.
This was an incredible experience and we learned many things... for
starters, the engineer must think about the construction phase when
designing. Things must make sense in real life! We designed a skewed
bridge with many angles that made the fabrication extremely complicated
and inaccurate.
Also, we
learned about cutting and welding. A student from Mechanical
Engineering helped us cutting many pieces and with the help of one of the ASCE
student's father, the welding could be possible. But since the
person who welded the pieces worked during the day, we had to work with
him at night which made this task even more difficult.
And
this teaches us to make a budget and better plan when developing a project
like this, many situations could have been prevented if we had taken care
of that before.
Images
of errors in Fabrication:
A
bolt was to be welded to the flat side of a 1" channel (One channel
on each side of the tube). A square tube had a slot that fit the bolt
heads welded to the channels. This was to connect 3 pieces, but the
welding on the bolts was too difficult, so when the bolts where to be
inserted in the tube the welding didn't allow it since it was taking more
space than designed.
Since
this bridge had so many angles, it was too difficult to make the pieces
match. Another difficulty was to make the drilled holes for the bolts for
the assembly to match all the pieces.
This
shows how the pieces in some places didn't match at planned.
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But we didn't consider the space needed to screw the nut in the bolt. The 1" channel flanges had exactly the space to allow the bolt throw but not enough for any tool to be used to put the nut and it was very difficult by had, without mentioning the strength needed to tide the bolt in place as required. |
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We had to remove part of the flange of the channels to be able to tide the bolts when assembling the bridge. This Obviously lowered the strength the channel was supposed to have when loading the bridge. |
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Since the welding was a night, it was extremely difficult to be accurate with the angles. Unfortunately when putting the pieces together such as in this location, the pieces don't match as needed and the bolts had to be forced in maybe with a hammer.
From a top view the horizontal and vertical tubes were supposed to look aligned. |
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When forcing some of the pieces together some members such as the bracing on the top chord was in compression instead of tension as intended in the design. |
All these mistakes and problems teach many important things for the future, not only with projects but in real life. I hope all this experience bring us better result in future projects.
