Tag Archives: slip-formed concrete

Revisiting Greenwood, Nebraska, and its Tillotson grain elevator

by kocart
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The Tillotson elevator and annex alongside the railroad tracks in Greenwood, Neb.

Story and photos by Kristen Cart

Along U.S. 6 between Omaha and Lincoln, Neb., stands an early testament to the ingenuity of the Tillotson Construction Company of Omaha. This early elevator, which rises alongside the highway next to its attached annex in the town of Greenwood, still holds grain. The original elevator was built with a capacity of 129,000 bushels. On the side facing the highway, stenciled in black, is a sign that says “Built by Tillotson Construction Co. Omaha Nebraska.” The lettering is partially obscured by paint and concrete patches.

Highway 6 is a very familiar stretch of road. I have driven it innumerable times between Ashland and Lincoln while visiting my family–on every run to Lincoln, the old Tillotson elevator and its annex come up on the right side of the road about a third of the way there. As a little girl, when traveling across Nebraska, I would see a white edifice on the horizon, and it meant a new town was coming up and we were closer to our destination. Now, living far away, I rarely see the elevators that have become so familiar. But last summer, I revisited this one.

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A Burlington Northern train slows to pass through town on an early morning run.

The Greenwood elevator was built in 1951. Its annex was added in 1954, and although we do not have the construction record of the annex among our Tillotson company papers, the embossed manhole covers identify its provenance.

The pairing of a Tillotson elevator with a Tillotson annex is fairly unusual in the company records–usually another company would come along and build an annex. During the elevator boom, it seems very likely that the Tillotson company was too busy to meet the demand for annexes that were springing up everywhere, and it is very doubtful that they competed and lost the contract at each site. The company was too good at what they did, and it is almost certain that they had more work than they could accept.

DSC_0421We have the building specifications for the original elevator in the Tillotson Construction Company records.

Greenwood’s elevator was built following the Churdan Plan, with four 14 1/2-foot-diameter tanks, 120 feet high, and a 13 x 17-foot driveway. The spread was 13 feet, and eight bins were built over the driveway. The plan called for 17 total storage bins and a dust bin, with bin number 8 split to accommodate a dryer. The total capacity was 129,000 bushels.

Grain capacity per foot of height was 1318 bushels. For the project the company poured 1255 cubic feet of reinforced concrete, and 25 cubic feet of plain concrete for the hoppers. 60.23 tons of steel were used for construction (including jack rods). The average weight of steel per cubic yard of concrete was 96 pounds. The plans broke out the concrete and steel to be used for each line item:

Below main slab: 3,200 pounds of steel; 30 cubic yards of concrete;

Main slab: 15,870 pounds of steel; 118 cubic yards of concrete

Draw-form walls: 82,377 pounds of steel; 934 cubic yards of concrete

Driveway and work floor (including columns): 3,370 pounds of steel; 26 cubic yards of concrete

Deep bin bottoms: 3,491 pounds of steel; 19 cubic yards of concrete

Overhead bin bottoms: 3,752 pounds of steel; 23 cubic yards of concrete

Bin root: 3,060 pounds of steel; 30 cubic yards of concrete

Scale floor (or garner), complete: 186 pounds of steel; 3 cubic yards of concrete

Cupola walls: 2,789 pounds of steel; 35 cubic yards of concrete

Distributor floor: 886 pounds of steel; 7 cubic yards of concrete

Cupola roof: 1,129 pounds of steel; 9 cubic yards of concrete

Misc (boot, leg, head, track sink, steps, etc.): 360 pounds of steel; 20 cubic yards of concrete

Attached driveway: driveway extension included above

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Concrete repairs are evident around the annex manhole cover.

Construction Details

The dimensions of the main slab were 49 x 49 feet, with a main slab area (actual outside on the ground) of 2,377 square feet. The total weight of reinforced concrete, at 4000 pounds per cubic yard plus steel, was 2,570 tons. Also computed at 4000 pounds per cubic yard, the total plain concrete weight for the hoppers was 50 tons. The fill sand for the hoppers, at 3000 pounds per cubic yard, was 360 tons. The planned weight of grain was 60 pounds per bushel, and when filled, the elevator could hold 3,870 tons of grain. Fifteen tons of structural steel and machinery were added to complete the planned gross weight, loaded, of 6,865 tons. The elevator was designed to withstand 2.89 tons per square foot of bearing pressure.

Greenwood 01The dimensions of the elevator were planned as follows:

Main slab thickness: 18 inches

Main slab steel: 1 1/4-inch square at 10-inch o. c. spacing

Tank steel and bottom for the round tanks: 1/2-inch diameter at 12-inch spacing

Lineal feet of drawform walls: 1,006 feet

Height of drawform walls: 120 feet

Pit depth below main slab: 12 feet 0 inches

Cupola dimensions (outside width x length x height): 17 x 34 x 22 feet

Pulley Centers: 145.67 feet

The elevator was designed to operate with one leg. A distributor floor, track sink, full basement, and electrical room were included in the plans. Two dump grates, 5 1/2 x 9 and 15 x 9 feet, were built. The columns under the tanks were 16 x 16 inches square, and the boot-leg and head were built of concrete.

Machinery details

Boot pulley: 60 x 14  x 2 2/16 inches

Head pulley: 60 x 14 x 3 15/16 inches

R.P.M. Head pulley: 42 rpm

Belt: 310 feet of 14-inch 6-ply Calumet

Cups: 12 x 6 inches at 9-inch spacing

Head drive: Howell 30 hp.

Theoretical leg capacity (cup manufacturer rating): 6,250 bushels per hour

Actual leg capacity (80% of theoretical): 5,000 bushels per hour

Horsepower required for leg (based on above actual capacity plus 15 percent for motor): 22 hp.

Man lift: 1 1/2 horsepower electric

Load out scale: 10 Bu. Rich.

Load out spout: 8 inch w.c.

Truck lift: 7 1/2 Ehr.

Dust collector system: fan to dust bin

Cupola spouting: 10-inch diameter

Driveway doors: 2 overhead rolling

Conveyor: none

Also built

Inside steps

Dryer provided (split bin)

 

 

 

 

 

 

 

Collin Quiring delivers a load of corn to Tillotson’s Aurora South elevator

by baggyparagraphs

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Collin Quiring, a 26-year-old reader of this blog who farms with his brother in Henderson, Nebr., made contact and offered to send some photos when he took a load of grain to the Aurora South elevator, which was built by Tillotson Construction Company in 1959.

Collin had first commented on one of Kristen’s posts.

A view of Tillotson Construction Company's Aurora South elevator, as seen Nov. 2, 2014, by Collin Quiring.

A portrait of Tillotson Construction Company’s Aurora South elevator, as seen Nov. 2, 2014, by Collin Quiring.

“It’s funny that you drove through Hampton,” he wrote. 

“I’ve been following this blog for a while now and started looking at all the manhole covers on elevators that I haul to, and sure enough there were a lot of Chalmers-Borton, Tillotson, and Mayer-Osborn elevators around.

Hampton has the manhole covers on the outside of the silos and they’re 10 feet or so off the ground, so I’ve been wondering who made it for a while now!

It looks like you just saw the one downtown elevator in Aurora though?

The other elevator is called Aurora South and is on the southwest edge of town. It used to be a Cargill elevator, but Aurora Coop purchased it.

I’m pretty sure that’s a Tillotson elevator, too.”

So Collin did some more reconnoitering and took pictures on his next run.

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Collin’s view from the scale house.

“We’ve been alternating where we were taking corn, and I was planning to get back there for a few more pics.

But harvest will be over in an hour.

So I won’t be getting back there anytime soon.

Here’s what I did get while trying not to hold up the line.

End of this week or beginning of next I will be hauling to Hampton and will send you some from over there.”

Two days later, he made the run to Hampton but found it was not a Tillotson elevator; instead, it was built in 1959 by Grain Storage Construction Company, of Council Bluffs, Iowa.

A recent trip west reveals mystery elevators

by kocart

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Story and photos by Kristen Cart

After our annual trip west to tease the elk (hunting them is perhaps too strong of a term, since our freezer has admitted no elk meat for several years), we took a small detour to look at elevators. I headed the car east onto Hwy 34 in Neb. after stopping to photograph the Grand Island, Neb. elevator, a Johnson Construction project.

This time my dad, Jerry Osborn, went with us, and he humored me, though he was eager to get home. The kids just rolled their eyes and said, “Not another elevator!”

Like pearls on a string, grain elevators line up on Hwy 34 as it stretches from town to town west of Lincoln, Neb. From the look of the rounded headhouses on each elevator,  Tillotson Construction Company of Omaha had free reign there during the construction years, having butted out potential competition as it changed the landscape on the old road.

Only the York and Aurora elevators are recorded in the company construction record pages we have. I will present them more fully in a later post.

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The Murphy sign stenciled on the elevator does not seem to be a town name

The Murphy and Hampton elevators present a bit of a mystery. Since I had a full load of family cramped together in a rental car that was barely an SUV, more suited to a terrier dog and a bicycle than the five passengers it claimed to hold, I did not stop to investigate the mystery elevators. I had to be content with a few pictures taken on the fly.

Here they are. I wonder if any of our readers remember these elevators, or can identify the builders? They will get another visit, hopefully soon, but for now, enjoy the photos.

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Hampton’s elevator also has a rounded headhouse

‘A Tillotson unique feature: the end of the headhouse is round’

by baggyparagraphs

Neil Lieb Collection

Commentary by Neil A. Lieb, photo from his archive

The concrete work is finished. You see those windows up there? The end of the headhouse is round because it’s hard to lay steel on a square corner. When you’re laying rebar, you have long straight sticks. Corners are hard to do. The is a Tillotson unique feature, as far as I know. It looks good because it matches the contours of the rest of the building. It was functional because the steel of the tank comes in about four pieces, and you lay them and they overlap. It was pretty exacting. You worked on your knees all night, up and down. You got the steel off the rack and you had to get down under neath and run it under all that stuff. And you did that over and over. The day that we were going to put the glass in the windows, those were steel-frame windows. There’s a little metal clip that holds the glass. You put the putty on the outside and you’re all done. The day we were doing that, the wind was blowing so hard, it was breaking the glass as we were put it in. We had to quit because of the danger of flying glass. They bought some different glass that was stronger, double-strength glass. It was just one of those things. All of a sudden, boom, this flying glass comes across the room at you.

Filled with concrete, a nail keg counterbalanced the rooftop crane

by baggyparagraphs

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Commentary by Neil A. Lieb, with photo from his archive

See the little cornice atop the tank? Those are forms for the cornice, the overhang. They call them eaves on a house.

The roof was poured before the headhouse went up.

That crane is a concrete-hoisting crane.

The headhouse is quite an operation because you had to hoist the concrete up to the top of the tank. And then they had a deck crane, and you had to hoist it [the concrete] to the top.

Every job I worked on, they used a nail keg that had been filled with concrete as a counterbalance weight. When you went up and down on the cable to go to work, that’s what you stood on—two guys, one foot each. That’s all there was room for.

It didn’t take that long, about fifteen or twenty seconds.

The motor and cable were down on the ground.

The operator had a shed to keep him out of the rain and sun.

 

DN Tanks builder explains differences between concrete tanks and elevators

by kocart
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A water tank built by D N Tanks in Cary, Illinois

Story and photos by Kristen Cart

At first glance, a water storage tank and a grain elevator seem to have a few things in common, both in function and appearance, though they present a number of differing engineering challenges. I had the opportunity to interview Joseph Carroll, a project superintendent for D N Tanks, while flying on a commercial airline to start one of my trips. When he realized the lady sitting next to him had some engineering background, and actually was interested in concrete construction methods, he warmed to his subject with enthusiasm.

I wanted to find out how the construction of a tank answered the problems that grain elevator designs had to address–the management of stress (both vertical and lateral), the aging of the tank, interior access, wrecking out, weather considerations, and basic construction methods.

D N Tanks had been in the business since 1949, and some of their tanks (still in service) were built before 1950. During the heyday of elevator building, when our grandfathers operated at the cutting edge of concrete design, water tank builders were innovating right alongside them. The types of problems they had to solve had common elements with those of elevator designers, but their solutions were widely divergent.

After looking at our Tillotson construction specifications, Mr. Carroll commented that the design bearing load (the pressure of the water against the tank walls, expressed in pounds per square inch) of his tanks is about double the bearing load in a grain elevator.  Elevator builders relied on a continuous concrete pour and steel reinforcement to provide the required strength. Obviously, something had to be done differently to build a water tank that would sustain that kind of load.

D N Tanks, instead, builds tank panels which are poured in curved sections separately, then tensioned externally with wire winding as they are assembled on site.

Cold weather also creates a design challenge for concrete construction. I mentioned that in Canada, wood construction for grain elevators was preferred, because rigid concrete could crack under differential heating–an elevator would experience freezing temperatures on one side and solar heating on the other. Water tanks require insulation to prevent freezing, though they can handle surface freezing to the depth of about six inches. The tank walls are built thicker, and an insulating material of styrofoam blankets the tank exterior for installations in Alaska and other northern locations.

After the concrete roof is poured, wrecking-out is required (internal wooden concrete forms are removed). It is a process required for both elevator bins and tanks. Elevators retain the manholes used to remove the wrecking-out debris for later access to bin bottoms for cleaning. For water tanks, an access opening is left at the side to permit this process, but it is sealed afterwards. No access is needed from the side, because under normal use, the tank remains filled with water. Access to electrical systems for the pumps is from the top.

Concrete elevators are subject to much more wear and tear than water tanks. Internal friction is an issue with grain elevators:  filling and emptying of grain bins abrades the inner concrete surfaces, eventually causing cracking and damage after many years.  Tanks suffer from no such problems.

Fire is an ever present danger in grain elevators, and cleanliness is a constant battle. Tanks tend to be cleaner and safer, and if built correctly from the start, will long outlast the most robust grain elevator.

DSC_9898I happened upon one of these water storage facilities, built by D N Tanks, while attending my son’s football game at Cary Junior High School in northern Illinois. It appeared just as Mr. Carroll described as a typical D N Tank project: it was bordered with a two-foot wide lip, and topped with a white vent.

The tanks are built in cities and towns to comply with a requirement for an emergency water supply. The tank or tanks must hold enough water to last for three days after normal municipal service is lost. Unlike the many grain elevators that dot the Midwest, which rise to monumental heights, these tanks are designed to blend seamlessly into the community with as little visual impact as possible. The D N Tank website pictures a number of disguises, including architectural treatments, and fully underground construction.

D N Tanks also produces tanks for glycol used for aircraft deicing, water treatment tanks, and various other tank types.

Summer 1950: All finished with the main house in Alta, Iowa

by baggyparagraphs

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Commentary by Neil A. Lieb and photo from his archive

From a telephone interview on July 22, 2014

It’s all done. It looks like they’re putting scaffolding up for painting. The main hoist is on the left. That’s a Georgia buggy hanging on the hoist. The guy that’s standing there is going to push it as soon as it hits the deck. They might be just starting on the headhouse. I can’t figure that scaffolding out. It’s a rigid scaffolding.

Memories of cranes and pushing the Georgia buggy in Alta, Iowa

by baggyparagraphs

The formwork is clearly seen at the Alta elevator rises. The catwalk around the bottom was for the concrete finisher, who smoothed and patched the freshly formed surface. Photo from the Neil A. Lieb Archive.

Commentary by Neil A. Lieb, photo from his archive.

From a telephone interview on July 22, 2014

On the upper left-hand corner, there’s a crane. That crane we used to haul the steel up to the top, the rebar, the jackrods. That’s all we used it for. You didn’t tie up the other hoist, you used that one. I think it’s called a jack crane. It was an electrically operated crane. The railroad tracks are on the bottom, that’s the end of a box car in the lower right. That doorway—that’s used when you’re loading grain after the thing was all over with.

When I first started, I pushed the Georgia buggy.  It’s probably the worst job in the world because it’s very physical. They weighed 1000 pounds. At Alta, I progressed to laying steel. All the new hires always got to push the concrete because that was the hardest work. There was a big turnover when you started out because pushing Georgia buggies wasn’t very much fun.

The Tillotson elevator in Boxholm, Iowa, afforded unique photographic possibilities

by kocart

DSC_0535Story and photos by Kristen Cart

The Boxholm elevator located in central Iowa was an intriguing destination, particularly since I had knowingly passed it by, missing it by a few miles on more than one trip. It became imperative to make the detour to see it. I was glad I did, since the elevator made beautiful pictures on that early summer day. I used a wide-angle lens that added pronounced distortion to the scene, causing the buildings on the edges to lean in dramatically. But the leaning lines pointed to the beautifully clouded sky.

You can use a wide-angle lens to include more of the scene from close quarters than would be possible with another lens, but you forfeit realism. This is not a problem for certain artistic photos, but it is not ideal for documentary shots. When photographing buildings where you want to preserve parallel lines, you must stand farther away and use a longer focal-length lens. At Boxholm, I did not have that option.

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Wide-angle lens distortion is maximized in this view.

At extremely close quarters, the wide-angle lens exaggerates height and adds drama. But the distortion becomes more pronounced.

The Tillotson Construction Company of Omaha, Neb., built the elevator in 1955. An annex stands beside it, and an old wooden feed mill is beside that. A much newer elevator with the West Central logo was built later, after it became customary to leave the concrete plain, without the white finish.

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A more conventional view of the elevator complex.

The specifications for the Boxholm elevator are among the Tillotson Company construction records. We learned some details about the elevator from a few stray sources before my visit; for instance, the elevator has exactly 96 light bulbs installed. Its construction followed the Drummond plan. Other projects using the same architectural plan were the elevators at Waverly, Neb., and Lahoma and Drummond, Okla.

Specifications

Capacity per plans (with Dock): 199,400 bushels

Capacity per foot of height: 2,002 bushels

Reinforced concrete per plans (total): 1,797 cubic yards

Plain concrete (3″ hoppers): 33 cubic yards

Reinforcing steel per plans (includes jack rods): 85.71 tons

Average steel per cubic yard reinforced concrete: 95.4 pounds

Steel and reinforced concrete itemized per plans:

Below main slab: 6,861 pounds steel, 59.2 cubic yards concrete

Main slab: 25,603 pounds steel, 202 cubic yards concrete

Drawform walls: 103,192 pounds steel, 1,295 cubic yards concrete

Driveway and Work floor : 3,820 pounds steel, 23.8 cubic yards concrete

Deep bin bottoms (including columns): 7,271 pounds steel, 39.3 cubic yards concrete

Overhead Bin bottoms: 6,040 pounds steel, 27.6 cubic yards concrete

Bin roof and Extension Roofs: 7,210 pounds steel, 41.7 cubic yards concrete

Scale floor (or garner complete): 160 pounds steel, 2.5 cubic yards concrete

Cupola walls (including leg & head): 7,257 pounds steel, 76 cubic yards concrete

Distributor floor: 1,560 pound steel, 9.4 cubic yards concrete

Cupola roof: 2,147 pounds steel, 15.6 cubic yards concrete

Misc. (track sink, steps, etc.): 173 pounds steel, 3.5 cubic yards concrete

Attached driveway: none

Bridge and/or Tunnel: none

Pit Liner–plain: 16 cubic yards concrete

Drier Bin Bottom: 134 pounds steel, 1.3 cubic yards concrete

Coffer Dam, Cleaner Floor: Wood

Remarks: 10 Bin Hot spot; 8 Bin Aeration tubes; Dryer bin

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The rounded headhouse is a reliable indicator of a Tillotson elevator

Construction details

Like Waverly: construction details were identical to Waverly and not listed separately in the records.

Main slab dimensions (drive length first dimension): 56 1/2′ x 70′

Main slab area (actual outside on ground): 3,850 square feet

Weight reinforced (total) concrete (4000 pounds per cubic yard plus steel): 3,747 tons

Weight plain concrete (hoppers; 4000 pounds per cubic yard): 98 tons

Weight hopper fill sand (3000 pounds per cubic yard): 732 tons

Weight of grain (at 60 pounds per bushel): 5,982 tons

Weight of structural steel and machinery: 20 tons

Gross weight loaded: 10,579 tons

Bearing pressure: 2.75 tons per square foot

Main slab thickness: 24″ with 3″ pile cap

Main slab steel: straight #9 at 7″ spacing

Tank steel and bottom (round tanks): #4 at 12″ spacing

Lineal feet of drawform walls & extension: 606′

Height of drawform walls: 120′

Pit depth below main slab: 15’3″

Cupola dimensions (outside width x length x height): 22 1/4′ x 48 1/2′ x 35′

Pulley centers: 160.75′

Number of legs: 1

Distributor floor: yes

Track sink: yes

Full basement: yes

Electrical room: yes

Driveway width clear: 13′

Dump grate size: 2 at 9′ x 5′ and 9′ x 15′

Column under tanks size: 16″ square

Boot legs and head: concrete

DSC_0531Machinery details

Boot pulley: 72″ x 14″ x 4 15/16″

Head pulley: 72″ x 14″ x 2 7/16″

R.P.M. Head pulley: 42

Belt: 335′, 14″ 6 ply Calumet

Cups: 12″ x 6″ at 8″ spacing

Head drive: Howell 40 horsepower [4 circled here]

Theoretical leg capacity (cup manufacturers rating): 8,440 bushels per hour

Actual leg capacity (80% of theoretical rating): 6,750 bushels per hour

Horsepower required for leg (based on actual capacity): 32 horsepower

Man lift: 1 1/2 horsepower Ehr.

Load out scale: 25 Bushel

Load out spout: 10″ diameter

Truck lift: 7 1/2 horsepower Ehr.

Dust collector system: Fan to bin

Cupola spouting: 10″ diameter

Driveway doors: 2 overhead rolling

Conveyor: provision

Remarks

see page 10 (above)

Night and day in 1950, Tillotson’s grain elevator rose in Alta, Iowa

by baggyparagraphs

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Commentary by Neil A. Lieb, photos from his archive

From a telephone interview on July 22, 2014:

It was commercial power for the lamps. The only thing that was noisy was the mixer and the hoist. Once you got about 40 feet off the ground, all that anybody heard was people talking to each other. That’s the top of the driveway (seen in the photo), about 16 feet, so they’re about 25 or 30 feet off the ground. On a construction site, there’s lumber all over everywhere. Today they keep track of it very carefully because people steal it. But when we were building these, nobody stole lumber. People in Iowa and the Midwest, they didn’t steal lumber from a construction site like they do out here (California.) See the scaffolding below the forms? A cement finisher finished the concrete as it came out of the forms. That’s all he did, all night long.

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Those cars…I didn’t have a car at Alta. Those shacks were probably, lower right, the office, and the other was where we kept the tools. We built a lot of those things and then we tore them down. Slip-form construction was a major engineering feat. They built concrete grain elevators before slip-forms. They had steel forms they’d fill with concrete.