20 Feb 2016

Lake Pontchartrain Causeway, And its Claim to ‘The World’s Longest Bridge’ Title

If you look at the list of the longest bridges in the world, you will notice that the top positions are dominated by Asian countries, especially China, which serves to testify the country’s rapid economic expansion. China produces and consumes about 60 percent of the world’s cement. To put that figure into perspective, here is a comparison — between 2011 and 2013, China used more cement (nearly 50% more) than the United States used in the entire 20th century.

In the last few years, China has been pushing the boundaries of bridge construction with many record breaking bridges that blow all competitors out of the water. The world’s longest bridge, for example, in China’s Jiangsu province, is a staggering 164 km in length. Out of the top ten positions, only two bridges lie outside Asia, in the United States, a country once known for its engineering and technological marvels. One of them is the Lake Pontchartrain Causeway that cuts straight across Lake Pontchartrain in southeastern Louisiana.
The Lake Pontchartrain Causeway is composed of two parallel bridges, each over 38 km long. One was completed in 1956 and the other, a slightly longer version, was completed in 1969. Since that year, it has been holding on to the title of ‘the world’s longest bridge over water’. In 2011, when a new bridge over Jiaozhou Bay in China threatened to rob Lake Pontchartrain Causeway of its coveted title, the Guinness World Records promptly created a new category to save USA from the embarrassment.

The Lake Pontchartrain Causeway was a monumental achievement for civil engineers, not only for its astonishing length, but also for the innovative techniques used in its construction. Prior to the Causeway's construction, the standard practice for bridge construction was to use solid square or circular concrete piles of 24-inches or less in diameter. The Causeway was the first bridge ever to be constructed using 54-inch in diameter hollow, cylindrical pre-stressed concrete piles that were larger and stronger than the norm, allowing fewer of them to be used and reducing costs.

Also unique at the time was the manner of construction. The Causeway was the first bridge ever to employ mass-production, assembly line techniques in fabricating and assembling a bridge. The bridge components were built in a state-of-the-art concrete casting plant on the shore of the lake in Mandeville, and then sent by barge to the construction site. Previously, bridge components were cast-in-place.









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