Mile 121.6 - RBD Hale Boggs - Luling Bridge

121.6 RBD Hale Boggs - Luling Bridge

The monumental cable-stay Hale Boggs - Luling Bridge is constructed of thousands of titanic plates of 1” steel, purposely let to rust, that gives the bridge its signature color of clotted blood. I-310 crosses here from Destrehan to Luling, and making easy access to I-10 and US 90 beyond. The cable-stay design makes for a gaping mouth of a center span of 1200 feet, hundreds of feet wider than what would be possible using the traditional steel truss design.

The best resource available online about Mississippi River bridges, John Weeks, offers a good description: The Hale Boggs Memorial Bridge, also known as the Luling Bridge, was the first major cable stayed bridge to be built in the United States. The bridge is somewhat unusual for a cable stayed structure in that is has very few stay cables. In addition, the deck is built like a box girder, which is a much more robust structure than typically seen on suspended bridges. The Hale Boggs bridge is a large structure. The entire bridge has nearly two miles of elevated structure (10,700 feet). The suspended spans include a 1,200 foot span over the river navigation channel, plus side spans of 495 feet and 508 feet. Add in two approach spans, and the large steel box girder structure is 2,744 feet long. The bridge towers soar 400 feet into the air, with the deck having 155 feet of clearance between the sea-level water and the low bridge steel over the navigation channel. The bridge at Luling is supported by 72 stay cables. They are arranged in 24 groups of either 2 or 4 cables. Each tower has 12 groups of cables, 6 groups on each side of the bridge deck. The stay cables are woven from 1/4-inch diameter wire. Individual cables have between 103 and 307 strands of wire. The cables were then coated with a protective polyethylene layer that ranges between 1/4-inch and 1-inch thick. This structure is not without its problems. Early on, it was noticed that the steel in the towers was rusting much faster than expected. This turned out to be a combination of a very humid environment coupled with poor airflow inside of the towers. Later, it was discovered that the protective coating on the stay cables was failing, which allowed water to seep into the cable bundles. This caused the cables to corrode in a location that could not be fixed. As a result, an estimated $20-million to $30-million will be invested in the bridge in 2009 to replace the stay cables, the first time such a project has been attempted in the US. Hale Boggs was elected to the US House of Representatives from Louisiana in 1940. He was instrumental in passing legislation that created the interstate highway system. While serving as the Majority Leader in 1972, the airplane carrying Boggs and Congressman Nick Begich disappeared over Alaska. The aircraft was never located. Boggs was declared dead in 1973. (John Weeks)