With piers rising up, beams spanning their tops and grids of green steel spreading across, now comes the heavy part: tons of fresh concrete.

Work begins Wednesday morning to pour concrete atop a new Kansas Turnpike bridge over North Third Street in North Lawrence. And vehicles passing down below will be steered out of the way.

Temporary lane closures on North Third — which also is designated as U.S. Highway 59 — are set to start at 7 a.m. and continue through mid-afternoon, said Rex Fleming, project engineer for the Kansas Turnpike.

Crews simply want to make sure that cement- and concrete-laced “moisture” won’t seep through the bridge’s bottom and onto traffic down below.

“We don’t want it to get on your car,” Fleming said.

At least one lane of traffic will be open in each direction at all times, Fleming said. Traffic on the turnpike will not be affected.