?The last pieces of piers that shouldered loads for the Kansas Turnpike’s original Kansas River bridges are to be blasted with explosives Thursday afternoon.

The scheduled demolition — to occur about 2 p.m. — will be expected to delay traffic for a few minutes before and after the detonation, as Kansas Highway Patrol troopers conduct “rolling road blocks” to keep traffic out of the area as a precaution.

The tops of two concrete piers already have been removed. Now what’s left — stretching 22 feet underwater and into the river bed below — will be turned to rubble with specially designed charges.

Crews already have drilled into the base of the piers, so the explosives will detonate beneath the river itself. Blast blankets will be in place atop the piers, to prevent flying debris.

The rubble, which will settle on the river bottom, will be removed by excavators.

Crews already are pouring piers for a new Kansas River bridge, one that’s being constructed alongside another span that opened last year. The work is part of a $130 million project to replace the 1950s-era bridges, overhaul interchanges and make other turnpike improvements.

Beginning Monday, the turnpike plans to close its East Lawrence interchange — that’s Exit 204, in North Lawrence — for seven months for reconstruction.