Deterioration of the steel that connected a 60-foot concrete barrier wall to the aging Polk-Quincy Viaduct appears at least partially responsible for that wall's having plunged to the ground Saturday, the Kansas Department of Transportation said.

That deterioration, combined with high temperatures, caused the barrier to break along an expansion joint of the viaduct, along which Interstate 70 passes through downtown Topeka, KDOT said in a news release late Monday.

"While it appears another break in the concrete barrier is unlikely, because temperatures are forecasted to be above 95 degrees throughout the week, KDOT is recommending people avoid the area as an added precaution," KDOT said.

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Topeka temperatures topped out at 93 degrees Sunday, according to the National Weather Service.

Kansas Secretary of Transportation Julie Lorenz went Monday morning to the scene of the wall collapse, where one lane each of westbound and eastbound traffic were continuing Monday to use I-70 on the viaduct.

KDOT stressed that its concerns involved the concrete barrier and not the structure of the viaduct, which remained open to the public.

KDOT said it was maintaining dump trucks on the closed outside lane of westbound I-70 on the viaduct Monday as a temporary barrier until repairs could be made.

"The safety of drivers and pedestrians is our top priority," Lorenz said.

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The collapse came at a time when motorists were continuing to use the highway's southern westbound lane but the northbound westbound lane was closed for maintenance work.

KDOT said it concluded late Saturday that further failure was "not imminent," and that it would keep dump trucks in the closed northern westbound lane "as a temporary measure to substitute for the barrier, allowing traffic to use the inside lane."

KDOT recommended that people avoid walking and driving on S.W. 2nd Street between S. Kansas Avenue and S.W. Van Buren Street, which is below the viaduct in the area involved.

The cross streets in that area will remain open, according to Monday's release

"This is a temporary closure until work can be completed on the viaduct to prevent additional breakages," it said.

"This additional precaution is to prevent injury to people walking or driving in the area if additional breakage of the barrier should occur, though it is unlikely," Lorenz said.

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KDOT in 1963 built the viaduct, an aging, elevated four-lane segment of I-70 that runs between S.W. Polk and S.E. Quincy streets.

Kansas Gov. Laura Kelly announced last July that as part of the Eisenhower Legacy Transportation Plan, the viaduct project had been put "into the construction pipeline" to be carried out.

The project is expected to cost $234 million. Topeka's city government is to pay $20 million of that, with the state covering the rest.

Tim Hrenchir can be reached at threnchir@gannett.com or 785-213-5934.