Easy Winter Construction of O’Toole’s Fertilizer Storage Dome—Step by Step in Pictures
The dome is complete, and the exterior door is added. Next is to add the conveyor equipment to the top.
Mike South / Monolithic Commons / CC BY-SA 4.0
Winter construction on a new fertilizer storage for O’Toole, Inc. in Letts, Iowa, went very smoothly despite the weather. One of the great things about Monolithic Dome construction is that most of the work is done inside and out of the elements. This project highlighted that advantage.
This fertilizer storage is a great example of the most efficient single-component dome storage that can be built. It is a simple design that holds 1500 tons of urea or any other product they wish to store. Mr. O’Toole mentioned more than a few times about how he would make money with this dome. The key for him was the ability to store the fertilizer long-term. He said that If his company can buy when the price is low and availability is good, then store it for the whole year, they will seriously increase their profit margins.
It was a great project. I’d love to be building lots of these simple storage buildings.
Almost finished digging the footing trench. Notice the elevation changes on the property. Domes are easy to build on a wide variety of surfaces.
Mike South / Monolithic Commons / CC BY-SA 4.0
This is the first phase of footing construction. We dig a 4’ deep trench to be below frost depth. After the trench is dug, we immediately fill that with non-reinforced concrete. This will ensure that we don’t cave in the trench while forming and reinforcing the structural footing.
Mike South / Monolithic Commons / CC BY-SA 4.0
The outer forms are ready, the forms for the step are set, and the rebar is tied. The rebar dowels will extend into the dome’s concrete shell. We pour a step into the footing for Airform attachment.
Mike South / Monolithic Commons / CC BY-SA 4.0
The footing is formed and ready for concrete. This dome is built close enough to the customer’s current blend plant so crews can easily unload the material into the existing weigh and unload stations.
Mike South / Monolithic Commons / CC BY-SA 4.0
In this image, you can see the unloading doorway section. This section is an extension of the dome that covers the doors to access and unload the materials.
Mike South / Monolithic Commons / CC BY-SA 4.0
The crew is adding finishing touches to the concrete that has been pumped into place.
Mike South / Monolithic Commons / CC BY-SA 4.0
Once the Airform is inflated, dome construction can continue, even when the weather turns on us.
Mike South / Monolithic Commons / CC BY-SA 4.0
Our crew takes pride in their rebar patterns. This is an excellent image of the rebar tied and ready for shotcrete. The scaffolding you see is called a Paxis 10 scaffold. The Paxis scaffold is designed, engineered, and manufactured by Monolithic.
Mike South / Monolithic Commons / CC BY-SA 4.0
Shotcrete takes a large concrete pump, an air compressor, a good concrete supplier, and a trained crew to apply. This image shows the air compressor on the left, and the concrete pump on the right.
Mike South / Monolithic Commons / CC BY-SA 4.0
This is inside the dome after the first few shotcrete layers are applied. Notice there is more rebar and concrete thickness on the base. The increased strength is there due to the pile of materials that will be resting against the dome.
Mike South / Monolithic Commons / CC BY-SA 4.0
Another image of the shotcrete progress.
Mike South / Monolithic Commons / CC BY-SA 4.0
A second mat of reinforcement was required at the top of the dome to help support and distribute the weight of the conveyance equipment that will rest on the top of the building. We spray and embed the first layer of rebar to ensure that it is well encapsulated, then install the second mats. Paxis scaffolding provides an excellent building platform.
Mike South / Monolithic Commons / CC BY-SA 4.0
The paxis rotating scaffold rotates on a center pivot point. The motor is variable speed. The best part of this scaffold is its huge working platform. Ten-foot wide scaffolding, with the ability to step the planks down the entire surface of the dome, creates an unmatched working platform.
Mike South / Monolithic Commons / CC BY-SA 4.0
The inflated dome during the shotcrete phase. The concrete pump is covered due to the freezing weather. The top of the dome has rebar dowels that extend through the dome membrane. These dowels will tie into a landing pad at the top of the dome where the conveyors will be mounted.
Mike South / Monolithic Commons / CC BY-SA 4.0
Monolithic Domes are naturally strong. We rarely need to add extra rebar or shotcrete when completely burying a dome. This project had an area where a few feet of the dome would be backfilled. The only extra thing we did was add an additional layer of the Airform fabric to protect the layer underneath from being punctured.
Mike South / Monolithic Commons / CC BY-SA 4.0
Once the dome is built, the interior concrete floor is poured.
Mike South / Monolithic Commons / CC BY-SA 4.0
This access hatch holds the dehumidifier system. This is one of the great things about fertilizer storage domes: this small, inexpensive, and quickly replaceable air conditioner has enough power to keep the material inside completely dry.
Mike South / Monolithic Commons / CC BY-SA 4.0
Located inside the tunnel, the bulk materials door, when raised, allows a controlled release of materials, making for easy handling by skid loaders.
Mike South / Monolithic Commons / CC BY-SA 4.0
Domes can hold an enormous amount of weight. This small conveyor is no problem for the dome to support.
Mike South / Monolithic Commons / CC BY-SA 4.0