Transportation officials say repairs to the Interstate 40 bridge over the Mississippi River at the Tennessee/Arkansas state line could take months after a crack was found. It was shut down Tuesday afternoon after inspectors found a “significant fracture” in one of two 900-foot horizontal steel beams crucial for the bridge’s integrity. Traffic is being rerouted to Interstate 55. The I-40 bridge, which opened in 1973, carried a 2020 average of 50,000 vehicles a day across the river, 25% of them commercial trucks.