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Multi-Span Bridge over US 90
Near the East Pearl River in Louisiana

Figure 1 is an old multi-span bridge (about nine spans) over the bayou on US 90. The photo was taken in Louisiana facing east toward the East Pearl River. The bridge consists of several approach spans on each end of the trusses and three truss spans near the center. The trusses are riveted steel pony trusses that were undergoing repainting when the storm hit. The brownish color on the right truss is a primer and the silver on the left is the original color. The debris on the south truss (right side of the photo) shows that high water was over the roadway by several feet. This measured almost 15 feet from the water level on the day of inspection.

Several attempts have been made to document high water. In most cases, a mud line was not visible so the best indicator was debris caught in trees. Sometimes there were “burn” marks on the vegetation from salty water. The utility pole shown in figure 2 is just west of the East Pearl River bridge on the north side of US 90. A DOT maintenance crew was interviewed at the site and pointed to the seaweed caught on the wire. They had talked with a person who rode out the storm in a shrimp boat who told them that the water was higher than the wires and within four feet of the top of a tall tree nearby. The pole was estimated to be 40 feet high. The eye of the storm was just a few miles to the east of this location.

Figure 1: The debris on the south truss shows that high water was over the roadway by several feet.

Photo:J. O'Connor (for MCEER)

Figure 2: Seaweed caught on the wires of this 40-foot utility pole indicates that the water level rose at least as high as the wires. The eye of the storm was a few miles east of the pole.

Photo:J. O'Connor (for MCEER)

 

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