CURRY-WILLE & ASSOCIATES
CONSULTING ENGINEERS, P.C.
425 S. 2ND STREET AMES, IA 50010
P.O. BOX 1732 515-232-9078
FLOODED GRAIN BIN CONCERNS TO WATCH FOR
With the recent flooding in the Midwest, many steel grain bins were exposed to unusually high-water conditions. During these flooding situations, many operators will have questions about what to do and how-to asses the damages.
While the water is still present there is vey little that can be done. It is safest to stay away from the bin until the water has subsided. Flood water can affect the grain a foot or more above the flood water level. This wet grain will fluidize and swell, causing bin wall pressure to increase 2 to 3 times normal pressures observed with stored corn and even more with soybeans.
After the water subsides it is recommended to asses the damages and determine the next steps. Remember that damaged bins can be dangerously waiting for collapse or serious failure without warning. All inspection should be done visually from a safe distance before approaching the bin. The following is a basic check list for preliminary evaluations of the grain bins and equipment after flooding:
- Visually determine if the bin is bulging or if grain is leaking out of the sidewalls. This is an indication of the bin failing or continuing to fail and is an extremely serious situation that could suddenly burst open. If this situation is found, discontinue any contact with the bin and seek professional assistance as soon as possible.
- Looking at the bin from a distance and see if the bin is leaning or has any damages associated with impacts from floating debris.
- Corrosion will not occur for some time after the flood but water will frequently accentuate previous corrosion particularly along the bottom sheets and anchorage
- Check bin wall access doors for alignment and if they are not closing or fitting properly or if there are missing bolts. Doors are sometimes affected by shifting in the bin or excess pressure from the wet grain.
- Slightly move slide gates to see if they are plugged or jammed with flood debris. Do not open them all the way until the handling equipment has been evaluated. Simply move them to determine if they are free.
- Check for missing or sheared stiffener or bin wall bolts. Missing bolts are easy to spot but sheared bolts frequently will stay in the sheet and can be found only by applying side pressure to the head. If any bolts of this type are found, discontinue any contact with the bin and seek professional assistance as soon as possible.
- After the bin has been determined to not have any damage which will cause immediate failure, check the exposed concrete for any cracks. Particularly cracks that are offset indicating a shearing of the concrete. While all concrete cracks, sheared concrete indicates uneven settlement.
- Look for any tilting or settlement of the foundation. This may be more obvious by leaning of the bin or egg shaping of the bin. This is also and indication of soil settlement problems.
- Frequently running water around the bin (surprisingly even at low flow rates) will cause the soil to be washed out under the bin foundation. If this situation is found, contact a professional. Simply replacing the washed material will not re-establish structural stability.
- Remember that water can change the properties of the soil during flooding but this potential problem and soil properties and bin loading can change after the water is gone. Problems associated with flooding can manifest themselves later.
- If soil correction was done for construction of the bin and foundation there is a higher probability that the soil conditions have changed due to flooding.
- Check anchor bolts for any locations where the bolt is pulled out, sheared off or the bolt is breaking off the edge of the concrete. This is an indication that the flooded grain has caused the bin move and a professional will need to evaluate the extent of the damage.
- Drain and clean out all equipment before any operations. Do not simply run the equipment to remove the water because this will likely result in damage to the equipment and the grain
- Check all bearings for rust and pitting and re-lubricate
- Check all components for corrosion and debris. The tails of augers and conveyors as well as bucket elevator boots are prime locations for old grain to become soaked with flood water
- Check all aeration tunnels and chairs for corrosion and debris. Previous fines and dirt become corrosive and difficult to remove after they are soaked with flood water
- Turn off all power before accessing any portions of the bin, drain all water and call a qualified electrician