I-10 Twin Span Bridge

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The I-10 Twin Span Bridge, known locally as the Twin Spans, consists of two parallel trestle bridges. These parallel bridges cross the eastern end of Lake Pontchartrain in southern Louisiana from New Orleans, Louisiana to Slidell, Louisiana. The bridges were opened at a short ceremony on December 21, 1965^[1] and are each constructed with 433 65-foot concrete segments.

[edit] Hurricane Katrina

After Hurricane Katrina on August 29, 2005, the Twin Spans suffered extensive damage. The rising storm surge had shifted bridge segments off of their piers or in some cases pulled them completely off the piers. The eastbound span was missing 38 segments with another 170 misaligned, while the westbound span was missing 26 segments with 265 misaligned. The damage to the Twin Spans and to U.S. Route 90 to the east left only one route into New Orleans from the east, the U.S. Route 11 bridge just west of the Twin Spans. The Louisiana Department of Transportation & Development (DOTD) accepted a bid of $30.9 million from Boh Brothers Construction Company on September 9, 2005 to reconstruct the bridges, starting with the less damaged westbound span. Phase 1 of the project was to reestablish two-way traffic on the eastbound span within 45 days. Scavenged bridge segments from the westbound span were used to fill in the gaps in the eastbound span. On October 14, 2005, the east span was reopened to traffic with one lane in each direction. Phase 2 of the project was occurring concurrently to Phase 1 and involved repairs to the westbound span. Prefabricated steel bridge spans were used on the westbound bridge in two areas to replace destroyed segments and segments used on the eastbound span. The west span reopened on January 6, 2006, returning 4 lanes of traffic to flow once again. Due to the prefabricated steel segments, there are both a 45-mile (72 km)-per-hour speed limit and weight restrictions on the westbound span. Additionally, the span is closed periodically for maintenance work, which is covered by Phase 3 of the original contract.

[edit] The New Twin Span

Following the extensive damages from Hurricane Katrina, it was decided that the current Twin Spans were too vulnerable to storm surge and that the long term solution would be to construct two new spans. Ground was broken on July 13, 2006 on the project which will construct two new bridges 300 feet (91 m) east of the current spans. This $803 million project will construct two 3-lane bridges 30 feet (9.1 m) above the surface of Lake Ponchartrain, with an 80-foot (24 m) high rise near Slidell. Each span will be 60 feet (18 m) wide, consisting of three 12-foot (3.7 m) lanes, and 12-foot (3.7 m) shoulders on each side.

The wider bridges will eliminate the bottlenecking that current occurs at both ends of the current bridges and also be able to accommodate 50 percent more traffic than the current twin spans, according to the Louisiana Department of Transportation and Development.^[2]

The new bridges will also have traffic cameras and electronic message boards to alert motorists of any potential problems on the bridge, much like the Lake Pontchartrain Causeway bridge.

The new westbound span is scheduled to open in 2009 with the eastbound span to follow in 2011. The old bridges will then be dismantled.

[edit] References

[edit] External links

• The New Twin Span Bridge website

Crossings of the Lake Pontchartrain West Maestri Bridge I-10 Twin Span Bridge East Fort Pike Bridge (Rigolets) Chef Menteur Bridge (Chef Menteur Pass)