To protect hay supplies from Oklahoma’s often-devastating weather, where wind gusts of 50-60 miles per hour are not uncommon, well-conceived shelters are a must.
“Producers often talk about the weather, but proper construction of hay shelters is one area where they can actually do something about it,” says Carol Jones, Oklahoma State University biosystems and ag engineer.
The most critical wind forces tend to pull the roof off the frame and poles out of the ground.
“If we’re looking at a partially filled building with the wind blowing in the open side, the force could exceed 20 lbs per square foot uplift,” she says. “For a 40 x 80’ building, this is equivalent to 32 tons of force pushing upward.”
So Jones suggests that the roof be tied down all the way to the ground. Roof frames and trusses or rafters should be fastened to supporting members with tie-downs such as storm clips, framing anchors and straps. Producers also should fasten support members and beams or girders to framing poles using bolts or pole-barn nails.
“Knee braces can be added to increase the strength and stiffness of these joints,” Jones says. “If constructing a new shelter, poles should be anchored in concrete rather than using tamped earth anchorages.”
The additional cost is minimal for building a new shelter or reinforcing an existing one, she adds.
“Hay supplies are a key part of most livestock operations’ profitability. It’s not worth risking a reduction in hay quality when it can be protected so easily.”