MANDEVILLE, La. — When the first span of the Lake Pontchartrain Causeway Bridge opened in 1956, at close to 24 miles, it was the longest bridge over water in the world.

“The concept of the bridge was actually a short cut for our folks on the north shore–actually people coming into New Orleans, not even from Mandeville or Covington, but, as a more direct route to the south shore for visitors coming in,” says Carlton Dufrechou, general manager of the Lake Pontchatrain Causeway Bridge.

It was a quicker and easier way to get to New Orleans. But, is was also a quicker and easier way to get to the north shore of the lake. And more and more people starting using the bridge.

“When the first bridge was opened in 1956, about 200,000 vehicles transited annually,” says Dufrechou. “About 1967, I believe it was, it was up to two million per year. And that’s when the Expressway Commission decided it’s time to build a second span. The north-bound span was completed in 1969.”

Besides being the longest bridge over water when it was built, it also was one of the most innovative.

“It was the first large-scale use of prestressed concrete and also of modular-component construction,” says Dufrechou.

The prestressed concrete pilings could withstand the greater force needed to drive them farther into the lake’s soft bottom, according to the American Society of Civil Engineers. And, the decks were built onshore and floated into the lake by barge to speed up construction.

Annual inspections and continuous maintenance have kept the bridge safe for drivers. And, improvements like stronger guard rails and new emergency pull-over areas under construction will make the bridge safe for years to come.

“The original design life of that original bridge was 30 years,” says Dufrechou. “It has exceeded that twice now because of the ongoing maintenance. And, there is no reason that if we continue like that–the bridge could continue to serve the region for decades to come.”