Drake Inc. • 402-362-1863 • http://www.drakeinc.net
Reprinted from GRAIN JOURNAL January/February 2020 Issue
Problem
A cooperative grain elevator suffered an explosion and fire that damaged two of its tanks, causing roof damage and smoke damage to the interior of the tanks.
Drake, Inc., a restoration contractor based in Waco, NE (402-362-1863), was retained to do the concrete repairs to the roof and restore the structural integrity of the tanks. The coop retained other companies to do the demolition work.
Solution
• The inside of the first tank suffered damage with deformed concrete toward the top of the slip wall. It was determined that a 10-foot shotcrete collar was necessary to strengthen that tank and also reinforce the areas around the beam pockets, so the beams did not have the option to slide out in the future.
• Also in the first tank, where there was smoke damage, Weatherzyme 727 was sprayed on and power-washed off to clean the concrete of smoke and odor from the fire.
• When the stiffening and deodorization was complete in the first tank, the focus switched to deodorization of the second tank with the Weatherzyme product. There was more thermal damage and spalling (a rough and flaky surface and breaking of some concrete chunks) in the second tank, because it was damaged by a hotter fire than the first tank. Drake’s crew installed a full 125-foot concrete structural liner with both rebar and shotcrete from the top of the hopper to just underneath the roof beams.
• Two lower drawspouts were damaged when the hot grain was unloaded from the tank, so a spout repair was needed. A rebar network was installed over the area around the spout, and shotcrete was applied to make a large concrete structural patch – approximately 10 feet by 10 feet – to ensure that there will be no further damage around the spout areas and prevent deflection of the wall.
- Jerry Perkins, contributing writer
The crew from Drake, Inc. pours concrete over rebar for the new roof.
Procedure
The roof repair involved cutting and demolishing any loose concrete that was left from the incident; installing new beams to support the roof decking; installing roof decking, rebar, new manholes and lids, construction rings for aeration, and spout blockouts; and forming cornice ledges in preparation for concrete pour. Concrete then was pumped and finished with positive drainage and curbs at penetrations.
Two completed tank roofs.
