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.

A satellite image of Lake Pontchartrain. The Causeway can clearly be seen bisecting the lake. Photo credit: NASA

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.

A comparison rendering of the two bridges, provided by the Lake Pontchartrain Causeway Commission.

When such a historic bridge was challenged by another bridge in another country, no less, it was almost natural for the bridge officials to get offended. So they started probing the Chinese claim and soon found a flaw.

The $2.3 billion Jiaozhou Bay bridge in the Chinese city of Qingdao measures 41.5 km, a little more than 3 km longer than the Causeway. But Causeway’s officials argue that some of that length comes due to a curve in the bridge. The actual distance traversed by the bridge over water is only about 25 km.

The Guinness World Records, which had already demoted the Causeway to No.2, decided that the best way to deal with the situation was to create a new category. Now the Lake Pontchartrain Causeway is the "longest bridge over water (continuous)" while the Jiaozhou Bay bridge is the "longest bridge over water (aggregate)."

The Causeway’s officials were relieved to have their title back, but not content. Causeway General Manager Carlton Dufrechou said they can even challenging Jiaozhou's aggregate length claim.

"The Qingdao Bridge curves and has three entry/exit points,” Dufrechou told Guinness. “We understand that all three legs of the bridge were included in the calculation of its cumulative length of 26.4 miles. The Causeway is actually two parallel bridges of 24 miles each with an aggregate length of 48 miles. The Qingdao's longest, point to point (direct) distance over water appears to be about 16 miles. The Lake Pontchartrain Causeway's direct, point to point overwater distance is 24 miles."

Lake Pontchartrain Causeway’s title will probably stay safe for at least a few years to come, if not decades. The Jiaozhou Bay bridge will however lose theirs once the Hong Kong–Zhuhai–Macau Bridge opens, possibly in 2017, but it can be as late as 2020. The new bridge which will connect Hong Kong, Macau and Zhuhai, will have an aggregate length of over 50 km over water. At least, the title will stay with China.

Lake Pontchartrain Causeway. Photo credit: Yan Runbo

Lake Pontchartrain Causeway. Photo credit: Robert Holmes/CORBIS

Lake Pontchartrain Causeway. Photo credit: Glenn/Flickr

Lake Pontchartrain Causeway. Photo credit: CNN

Satellite image of Jiaozhou Bay bridge. Photo credit: Dailyoverview

Photo credit: unknown

Photo credit: News.cn

Photo credit: Getty Images

Sources: Wikipedia / NOLA / NOLA / NOLA