I-10 Twin Span Bridge

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I-10 Twin Span Bridge
Carries	4 lanes of Interstate 10
Crosses	Lake Pontchartrain
Locale	New Orleans and Slidell, Louisiana
Maintained by	La DOTD
Total length	5.4 miles
Clearance below	8.5 feet and 65 feet at the bascule bridge section
AADT	55,000
Opening date	1963
Destruction date	Approx 2011

The I-10 Twin Spans should not be confused with the Lake Pontchartrain Causeway, which crosses Lake Pontchartrain between Metairie, Louisiana and Mandeville, Louisiana.

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 in 1963 and are each constructed with 433 65-foot concrete segments.

[edit] Hurricane Katrina

After Hurricane Katrina on August 29th, 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-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

I-10 Twin Span Bridge (new)
Carries	6 lanes of Interstate 10
Crosses	Lake Pontchartrain
Locale	New Orleans and Slidell, Louisiana
Maintained by	LaDOTD
Width	60 feet (18 m) each span
Opening date	2009 (westbound) 2011 (eastbound)

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 east of the current spans. This $803 million project will construct two 3-lane bridges 30 feet above the surface of Lake Ponchartrain, with an 80-foot high rise near Slidell. Each span will be 60 feet wide, consisting of three 12-foot lanes, and 12-foot shoulders on each side. Plans call for the new west bound span to open in 2009 with the eastbound span to follow in 2011.