After Hurricane Katrina's devastating effect on Louisiana's infrastructure, rebuilding the Twin Span Bridge was a
two part project: First to restore the existing bridge, then to completely rebuild a bigger and better bridge.
By Dani Smith
Hurricane Katrina was one of the most
damaging, natural disasters in U.S. history. Its
effects to Florida, Mississippi and especially
Louisiana were devastating to both residents
of these states and the nation as a whole.
It claimed the lives of roughly 1,800 people and caused
damages of upwards to $ 81 billion, making it clear that this
natural disaster's wrath was one to be reckoned with, as six
years later the cleanup is ongoing. Upon some of the major
damages in Louisiana was the Interstate 10 freeway, named
Twin Span Bridge. Spanning 2, 460 miles from Santa
Monica, Calif., through Jacksonville, Fla., the Interstate 10
freeway is an integral part of the nation's transcontinental
highway system and connecting New Orleans, La., to
Slidell, La., across Lake Pontchartrain. Two parallel trestle
bridges raised nine feet above water, the original bridge
carried 55,00 daily commuters. Therefore, when Hurricane
Katrina hit on Aug. 29, 2005, severely damaging both of
the 5.5 mile long parallel structures, misaligning over 400
bridge decks and destroying 58 decks, it was imperative
that Louisiana not waste any time in getting these roads
in traveling condition as quickly as possible. "The bridge
was totally impassable, so the decision was swiftly made
to first repair the existing bridge to allow traffic to return
to the I-10, and then to construct a new Twin Span
Bridge," explained Walter Bruce Perdue, assistant district
administrator of engineering for the Louisiana Department
of Transportation and Development (LDOTD).
Getting the I-10 freeway up and running was a twopart
process. Restoring the original bridge, constructed in
1965, was the first order of business, starting with the least
damaged bridge -- the eastbound bridge -- by turning it
into a two-way traffic pass in only 40 days. "The eastbound
bridge was temporarily repaired using segments from the
more heavily-damaged, westbound bridge, and a single
lane of traffic in each direction was placed on the bridge in
October 2005," explained John Horn of Volkert, Inc., who
served as project engineer for the construction engineering
and inspection component of the project. He added, "The
construction team used temporary metal acrow bridge
components to repair the westbound bridge." The Twin
Span Bridge was completely restored to four lanes of traffic
on January 6, 2006.
The next order of business for the Twin Span Bridge was
completing a new and improved Twin Span Bridge adjacent
to the original bridge. The idea was to have the original
bridge as a temporary fix and use the new and improved
bridge as the new route of the I-10 freeway. As Louisiana
Governor, Bobby Jindal stated, "We knew it wasn't enough
to just rebuild what Katrina destroyed. We were determined
to build back bigger and better than ever before." Using
a high-performance concrete that is stronger, denser and
less porous than regular concrete, the bridge-designed for
a 100-year lifespan, is more resistant to saltwater-induced
corrosion. "The traditional design allowed the construction
to be repeatable and swift from bent to bent. Highperformance
concrete was used to obtain higher strength, lower permeability
and increased durability," said Perdue.
Horn explained, "The innovative design of the bridge makes
use of reinforced concrete walls that act as restraining
walls to prevent the bridge girders from moving laterally
or lifting, or lifting upward." He added that this increases
the bridge's system storm surge resistance and will help
minimize damage in the event of a barge collision." The new
Twin Span Bridge is also equipped with state-of-the-art,
fiber optic technology to support Intelligent Transportation
System (ITS) tools including video cameras and dynamic
message boards. "The ITS tools will allow DOTD personnel
to rapidly and efficiently monitor and manage traffic
conditions on the bridge," Perdue mentioned.
Funded by federal tax dollars from the Federal Highway
Administration, on June 1, 2006, construction on the
new bridge began. By April 7, 2010, the first of the new
structures was completed and by September 8, 2011, the
second structure was completed. A project spanning over
six years from restoring and rebuilding, in a town crippled
by the aftermath of a hurricane, these new bridges had
many challenges associated with it. "The first challenge
was establishing and maintaining traffic to and from New
Orleans to support the massive recovery and reconstruction
efforts within the city. The existing bridges required
constant inspection and maintenance to withstand the very
heavy truck traffic supplying services and materials to New
Orleans," explained the project's engineer for construction
engineering. Because the original bridges were only to be
used as a temporary fix, their condition was such that it
was necessary to rebuild the Twin Span Bridge as quickly
as possible, creating for a tight construction schedule that
required two separate construction contracts and as many as
500 workers. Horn also explained that the design and bid
portion of the project was accelerated as well, resulting in
geotechnical exploration continuing into the construction
of the new bridges. "Keeping pile production ahead of
schedule was a constant challenge that required significant
coordination between the geotechnical staff, the contractor
and fabricator," he said. Glenn Schexnayder, the project's
manager for the contractor, Boh Bros. Construction, said
that his challenges were faced by way of water and transport.
"Challenges associated with construction of the bridge
were the marine access to the work, concrete delivery
over water and working next to the interstate traffic were
just a few faced on the project." He continued, "Having
sufficient marine transport equipment, barges and tug
boats to ensure that material deliveries were made to work
on time. An onsite traffic control manager helped ensure
all traffic control devices were in place and functioning as
per plan." While each team member on this project had its
own set of problems and solutions, Perdue's analysis sums
it up best. "In a word, I think the biggest challenge was
coordination. Several sections within DOTD were involved
(bridge design, road design, geotechnical design, fabrication,
construction and others). A consultant (Volkert, Inc.) was
hired by DOTD to perform construction engineering and
inspection, and there were three, prime contractors on six,
separate DOTD contracts," explained Perdue. "While there
were issues to be resolved on all contracts, there was a strong
partnering effort by all parties and the issues were resolved
one by one with no major delays."
The new $803 million Twin Span Bridge opened on Sept.
8, 2011, at which time the original twin span bridge was
retired and all traffic on the I-10 was redirected to the new
bridge. Standing at 30 feet above the water of the lakes,
compared to only nine feet for the old structure, the new
Twin Span Bridge also has a high-rise navigational section
that provides 80 feet of navigational clearance for marine
traffic. According to Horn, like its predecessor, the new
Twin Span Bridge consists of two parallel bridge structures
across Lake Pontchartrain. The bridges are approximately
5.5 miles long and 60 feet wide. Each accommodates three
12-foot travel lanes in addition to two 12-foot shoulders.
"The new bridge is taller, wider and stronger than the
original bridge. The new bridge will not only be able to
better withstand the forces of Mother Nature, but it also
increases vehicle capacity and improves traffic flow between
New Orleans and Slidell," mentioned Perdue. "The new
Twin Span Bridge is one of the largest public works projects
in Louisiana history. It's completion marked a significant
milestone in the recovery of the Gulf Coast region in the
aftermath of Hurricane Katrina."
While the old bridge is no longer used for traffic, it is
still being put to good use. According to Perdue, a section
of on the Slidell side of the bridge was purchased by St.
Tammany Parish and is being converted into a fishing
pier, two artificial reefs are being constructed in Lake
Pontchartrain by the Louisiana Department of Wildlife and
Fisheries, and the remainder of the old bridge is being used
for a shoreline protection project by the Louisiana Office of
Coastal Protection and Restoration. In the spring of 2012,
the old bridge will be demolished, making the project a total
of a seven years including: Repair of the original bridge,
construction of the new bridge and demolition of the old
bridge. "The goal was to quickly replace the existing Twin
Span Bridge that was all but destroyed by Hurricane Katrina
and restore this crucial link along the I-10 corridor in and
out of New Orleans," said Perdue. "I think our goal was met
and we were also able to make beneficial use of the original
structures by providing a fishing pier, two artificial reefs
and shoreline protection." He added, "Mother Nature dealt
the Gulf Coast a severe blow with Hurricane Katrina, but
countless people worked together to not only replace this
critical link of !-10, but to make it better."
Dani Smith is editor of American Infrastructure. She may be
contacted at dsmith@penpubinc.com
Twin Span Bridge
