Officials always had planned for the demolition to happen in two phases.

Ramps from Chesterfield Airport Road and North Outer Road to westbound Highway 40 are set to close at 9:30 a.m.

Ramps from Highway 94 and Research Park to eastbound Highway 40, and the ramp from Boone’s Crossing to westbound Highway 40 will close at 9:45 a.m.

The Boone Bridge consists of three separate spans (at least until Wednesday morning), including the old three-lane westbound span being knocked down.

MoDOT built a new eastbound bridge, and rehabbed the old eastbound bridge for westbound traffic.

The eastbound lanes opened to traffic in June, followed by the westbound lanes in early November.

The first blast on Feb. 18 took down part of the old westbound Boone Bridge. Chunks of the old bridge, which opened in 1937, landed in the Missouri River, where crews picked up the debris using cranes.

A total of $125 million has been allocated for the project, MoDOT said.

If you want to watch the demolition, park at the Chesterfield Valley Athletic Complex at 17925 North Outer 40 Road and walk down the Monarch Levee Trail for roughly a mile to a viewing area.

And the rule barring drones applies as it did during the first blast; the Spirit of St. Louis Airport is nearby.

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