Crescent City Connection
Coordinates: 29 ° 56 ′ 19 ″ N , 90 ° 3 ′ 27 ″ W.
| Crescent City Connection | ||
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| use | Road traffic | |
| Convicted |
 US Route 90 Business
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| Crossing of | Mississippi River | |
| place | New Orleans , Louisiana | |
| construction | two cantilever bridges | |
| overall length | 920 m (main bridge) | |
| width | 16 m (south bridge) 28 m (north bridge) |
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| Number of openings | three | |
| Longest span | 480 m | |
| Clear height | 45 m | |
| start of building | 1955/1981 | |
| completion | 1958/1988 | |
| planner | Modjeski & Masters | |
| location | ||
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Crescent City Connection (CCC), formerly the Greater New Orleans Bridge (GNO), describes two parallel, similar-looking steel truss bridges over the Mississippi River in New Orleans , Louisiana , USA .
Both bridges each have four lanes in one direction, the northern one also has two HOV lanes, the direction of which changes depending on the volume of traffic.
They report to the Louisiana Department of Transportation and Development .
location
US Route 90 Business , which crosses the bridges, connects central New Orleans with the right bank areas. Some of the bridges are on the left bank of the Mississippi, which flows north here, in the New Orleans metropolitan area. Over the right half of the river and a barely 300 m wide bank they stand in the area of the town of Gretna , which is further south on the right bank , the administrative seat of Jefferson Parish . The subsequent ramp bridges and the former toll station are in the Algiers district of New Orleans .
The Crescent City Connection is the last bridge connection over the Mississippi, and it is also the busiest bridge below St. Louis , Missouri . Their length including the approach bridges, all driveways and the former toll station is given as 4093 m (13,428 ft ).
South Bridge (1958)
The older, southern bridge was built between 1955 and 1958. It was the first river bridge in the city of New Orleans and after the approximately 16 km upstream Huey P. Long Bridge, the second south of Baton Rouge .
The bridge originally called Greater New Orleans Bridge ( GNO for short ) is a 920 m (3019 ft) long steel truss cantilever bridge with a 480 m (1575 ft) wide main opening. It has two unequal side openings, one on the left bank of the river with 260 m (853 ft) and one above the right bank with 180 m (590 ft). Their clear height is 45 m (150 ft) above MHW . Many ocean-going ships can pass this way, but not most of the cruise ships that dock at a terminal directly below the bridge.
Their superstructure is 19.5 m (64 ft) wide. Between the lower chords is the deck for the four 15.85 m (52 ft) wide lanes, which are accompanied on both sides by 0.9 m (3 ft) wide strips for the guardrails .
From a structural point of view, it is a Gerber girder bridge with a 210 m (689 ft 4 7/8 ″) long suspension girder, which supports parts of the trusses that protrude from both sides 135 m (443 ft) into the main opening and function as cantilever girders . It was thus the cantilever bridge with the third largest span (after the Québec Bridge and the Forth Bridge ), but it had the longest suspension beam in the world.
The superstructure was largely built from profiles that were provided with elongated holes to save weight (instead of the previously usual narrow profiles reinforced with diagonal connections). These hole profiles had previously been used on a trial basis in certain areas of the Huey P. Long Bridge. After extensive testing at Lehigh University , they were first widely used at the Greater New Orleans Bridge.
The pillars with two reinforced concrete shafts on a base were built with great effort in the difficult soil conditions. Their foundations were clad with granite in the area between the low and high water marks.
The ramp bridges consist of two fields on the left bank and three on the right bank, followed by fields with steel girders, each on concrete supports.
The bridge was planned by Modjeski & Masters , the office founded by Ralph Modjeski and continued by Frank M. Masters , which was also responsible for construction supervision. The planning was based on wind speeds of up to 240 km / h (150 mph).
The actual construction began in March 1955. A restricted traffic opening took place on April 15, 1958. After completion of the remaining work, the formal opening took place on October 18, 1958.
Northern Bridge (1988)
Due to the increased volume of traffic, another bridge was necessary, which was also planned by Modjeski & Masters and built 100 m further north between March 1981 and September 1988. With six lanes it is significantly wider than the older bridge, but otherwise looks very similar and has practically the same dimensions. In their construction, of course, the developments of the past 30 years have been taken into account, in particular with the calculation methods, the use of different steels and the use of modified joints in the suspension brackets. Your ramp bridges have no lattice girders, but consist entirely of solid wall girders .
It was painted an aluminum gray color that was also used a few years ago when the older bridge was renovated.
In 1989, both bridges were named Crescent City Connection , which was chosen from proposals submitted by the population. Crescent City is the name of New Orleans derived from its crescent-shaped floor plan, which is reminiscent of the waxing moon.
Hurricane Katrina
The two bridges survived Hurricane Katrina at the end of August 2005 largely unscathed. However, the Crescent City Connection gained notoriety immediately afterwards when a few hundred people attempted to escape from the flooded parts of New Orleans over the allegedly only remaining bridge on September 1. In the general chaos, the (by no means responsible) leaders of the city of Gretna and Jefferson Parish, which were less affected by the hurricane, arranged for the local police to close the bridge and drive the people back to New Orleans with warning shots.
See also
Web links
Individual evidence
- ↑ The former Crescent City Connection Division was integrated into the Department of Transportation and Development on January 1, 2012 (cf. Andrea Shaw: Crescent City Connection Division already merging into transportation department. Article of November 21, 2012 on NOLA.com | The Times -Picayune)
- ↑ a b c d e Modjeski and Masters: Greater New Orleans Bridge over the Mississippi, Final Report to the Mississippi River Bridge Authority. January 1960 ( digitized from Hathi Trust Digital Library)
- ^ RJ Bennett: Analysis of Crescent City Connection (Greater New Orleans Bridge No. 2). Bridge Engineering 2 Conference 2007, April 27, 2007, University of Bath, Bath, UK
- ^ Carol Kopp: The Bridge to Gretna. Article dated December 15, 2005 on cbsnews.com
- ↑ Brock N. Meeks: Gretna mayor defends bridge blockade. Article dated September 22, 2005 on nbcnews.com
- ↑ Crescent City Connection blockade after Hurricane Katrina wasn't illegal, US Justice Department says. Article from September 30, 2011 on NOLA.com | The Times-Picayune