TEEX Bridge Maintenance Tour
The Bridge Maintenance Course offered the Texas Engineering
Extension Service (TEEX), a member of the Texas A & M
System, trains public works employees how to perform
bridge inspections and maintenance operations—two tasks vital to
ensuring the safety of our nation’s bridges. So when TEEX discussed
creating a build in Second Life to support their existing training programs,
staff members thought a bridge maintenance tour may be a
good start. “We wanted to make something
that would be of real benefit to those that
would visit the build, and could be of interest
to a variety of visitors,” said James Matney,
project manager for TEEX—also known as
TEEX Clary in Second Life (SL). “Because of
recent incidents within the U.S., we thought
providing information on common bridge concerns
would be a welcomed build.”
Because TEEX has six other divisions with training in related areas,
the staff had considered other types of builds. “Initially there was
the idea of creating a virtual version of our famous Disaster City and
Brayton Firefield training areas,” said Matney. “These would have
potentially provided some aspects of virtual training in search and
rescue, and firefighting. Also, it would have allowed for a virtual tour
for these often off-limits’ facilities. But, the fact that TEEX’s entry
into SL coincided with the creation of Public Works island presented
an ideal opportunity for TEEX to contribute to what is already a
great fixture in SL.”
CONSTRUCTION BEGINS
TEEX Clary began construction of the Bridge Maintenance Tour in
October 2007 on the Public Works sim, an island in Second Life established
to provide a resource for public works professionals and
engineers. “This is TEEX’s first build, and the bridge is convenient in
its relative simplicity,” said Matney. “Building the bridge was a learning
process that started with large prims. Then development of the
informational station podiums provided for
some experimentation with basic sculpted
prims and scripts for interaction. I can see
future builds being more complicated, detailed,
and interactive, whether we develop
more skills in-house, or by outsourcing to
professional developers.”
As Matney planned his SL build, he faced
the initial frustration felt by most who are familiar with popular modeling
programs—there is currently no easy way to import CAD files
into SL. “First, we planned to use a previously developed 3-D model
of a newly built local bridge as a benchmark for the build, but we did
not have an easy way to import the model. However, the bridge’s
parts were very simple to rebuild in SL.”
Once the bridge was in place, Matney started to place information
stations at specific bridge elements. “We used our Bridge Maintenance
flier for content,” said Matney. “When we had a couple stations
ready, the bridge was reviewed by our bridge maintenance expert ,
Ralph Banks, P.E., TEEX adjunct instructor for bridge maintenance.” Banks made sure that specific components were focused upon. “Examination of a typical roadway bridge structure for maintenance
issues usually requires a methodical and relatively comprehensive onsite,
sequential examination for maintenance needs of the bridge’s
various components and their parts which are referred to as elements,”
said Banks. ” Most bridges consist of deck, superstructure,
substructure, approaches and channel components, with many different
maintenance issues possible within each component.”
Matney and Banks decided to use a notecard distribution system to
convey information. “To develop the information, Banks reviewed a
slideshow presentation with a number of the core bridge maintenance
issues,” said Matney. “From there we tried to incorporate as many of
the reviewed issues as possible. Most of the stations include a button
that demonstrates what needs to change in order to keep the bridge
best maintained.”
FINAL REVIEW
After Matney completed the build, Banks provided a final visual review.
Matney said, “He suggested corrections in some areas, including
slight changes with the bridge marker signage, and changes in
the bridge’s drainage to make it more authentic and applicable for
what it was intended to demonstrate.”
Communications director, Jay Socol, provided a final review of the
notecard information. Once those text changes were made, the
bridge was officially “open.” Socol and Matney introduced the bridge
maintenance tour sim to their public works director and some other
folks at TEEX. “They asked a ton of questions, but not in a negative
way,” said Socol. You could tell that they were trying to fully gauge
the potential of this newly revealed tool. The wheels are twirling in
their heads—it’s only a matter of time before we shift our SL walk
into an SL jog.”
Socol would like to
see the build generate
interest in
the real life course,
“Routine and Preventive
Maintenance
of Bridges,”
that is offered by
the Engineering,
Utilities, and Public
Works Training
Institute (EUPWTI)
division of TEEX
through the federally
funded Local
Transportation
Assistance Program, or LTAP. “I want this information to reach new
people. I’d like it to result in people taking our bridge maintenance
course or investigating other training made available by TEEX,” said
Socol. “Internal to TEEX, I’d like our other operating divisions—fire,
search/rescue, law enforcement, etc.—to be excited about it enough
to seek our help in finding their own presence in SL. That’s when I’ll
know we’re succeeding.”
Matney also sees the SL bridge tour as an opportunity for TEEX to
participate in keeping people in general informed on concerns in their
community. “We can also use the bridge as a guided tour of issues for
county officials and engineers. Eventually, the bridge could be used
within actual lectures and classroom training.”
The TEEX bridge is SL is modeled after a real life bridge that
crosses a state highway across a small stream. It consists of
two simply supported precast, pre-stressed concrete I-shape, multiple
girder spans. In addition to the two end abutments, the bridge
is supported by an interior substructure support (bent) consisting of
three equally spaced, vertical cast-in-place, round concrete piling
(called drilled shafts) topped with a horizontal cast-in-place crossmember
called a bent cap.
The end abutment supports are of design similar to the interior support,
including bent caps, only the vertical cast-in-place piling are
not visible due to the presence of earth slopes at the abutments
which are further paved with cast-in-place concrete slab slope protection.
The ends of each of the longitudinal superstructure girders rest on
rubber-like, elastomeric pads (called bearing pads) that in-turn, rest
on the abutment and interior support bent caps. These elastomeric
pads through stretching or otherwise deforming, enable the spans to elongate with warmer weather, then contract during
cooler weather, without structural damage to the
bridge or pads themselves.
The roadway deck of the bridge consists of a lower
portion of flat, pre-cast, pre-stressed concrete panels,
with the upper portion of the deck being cast-in-place
dense concrete. The lower portion panels of the deck
also served as stay-in-place forms for the deck system
during construction. The bridge railing along
either side of the roadway is of cast-in-place concrete
construction that has been engineered to retain most
impacting errant passenger vehicles within the roadway,
with minimum injury to vehicle occupants, and
minimum damage to the vehicle and the bridge itself.
Transverse, expansion joints, are provided at both extreme ends of
the bridge roadway to accommodate the natural expansion of the
bridge during warmer periods of the year. These joints have further
been provided with seal elements to avoid drainage from the roadway
flowing down through the joint openings. This drainage could
eventually prove harmful to other structural elements underneath
the deck.
The bridge approaches consist of cast-in-place approach roadway
slabs to enable smoother entrance onto the bridge, as well as
smoother exits away from the bridge. Approach rail has been provided
along either edge of the approach roadway, which has been
connected structurally with the bridge rail ends to enable any impacting
errant vehicle to slide along the combined connected together
railing and slow velocity. The extreme ends of the approach
railing away from the bridge proper are protected with impact attenuation
devices to minimize the crash effect to any impacting errant
vehicles.