Professor’s computer program simulates damage to I-40 bridge

MEMPHIS, Tenn. (WMC) – The specific design of the I-40 bridge in Memphis contributed to the fracture and could cause more problems in the future, according to an engineering professor at the University of Memphis.

Dr. Adel Abdelnaby has created a new computer program to simulate the wear and tear of the I-40 bridge. He says the very reason Memphis residents love the bridge, the iconic M-shape, is what makes it so vulnerable.

The movements in his simulation, which he showed at WMC Action News 5, are exaggerated for better visualization of what happens during cyclic loading as trucks and cars cross the bridge. His model shows the load path, the transfer of weight throughout the structure.

“This type of truss system with cables suspended to support the bridge deck is not an idea,” he said of the new bridge and its arches.

The length of the I-40 bridge, which spans more than three miles, is also an issue.

“This span is too long to do this type of truss with cables,” he said. “It’s ok for half the duration. Its good.”

The result, he said, is stiff cables on the sides and flexible cables in the middle, creating uneven weight distribution and pressure near the bottom of the middle part of the M-shape where the fracture is. is produced.

Using a short, thin piece of metal, Abdelnaby explained how the joint occurs and the impact of the joint on the steel beam that fractured.

“It bends more on the higher side,” he said. “Bend more that way, bend like that. That’s why the crack happened at the top, not the bottom. The crack started at the top where there is higher tension, then compression at the bottom.

Abdelnaby says the key for engineers repairing the bridge is to make sure the weight doesn’t transfer to other weak points.

“Because it happens often,” Abdelnaby said. “You go to reinforce a section and the load path finds the weakest link to break. So he will find another weaker place to break. Make sure that won’t happen and it will be an easy fix.

Tennessee Department of Transportation officials said they may release a timeline this week on when the bridge will reopen. The second phase of repairs has not yet started. US Transportation Secretary Pete Buttigieg will travel to Memphis on Thursday June 3 to provide an update on the I-40 bridge, which has been closed to traffic since May 11.

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Gordon K. Morehouse