Making sense of a chimney near a wooden elevator in Alta, Iowa

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Commentary by Tim Tillotson, photo from the Neil A. Lieb archive

Note: What follows is from a phone interview on May 14. Uncle Tim is speculating about the reason why some Tillotson Construction Company employees stayed behind for this small job after completing the concrete elevator at Alta, Iowa, in the summer of 1950.

That chimney is probably about 30 inches in diameter. They’ve got a mortar mixer down there for masonry, a hand line going up, and the framework is scaffolding. The building in front is eight-inch block. Every three blocks is two feet. The building is 12 foot to the eaves.

There’s a reason for that damn stack, and it’s got to have something to do with fire down below. [Brother] Charles [Tillotson] said it could’ve been an iron-working shop.

Why does that car have chock blocks front and rear? Is it some kind of an anchor? It’s a 1935 or 1936, possibly DeSoto.

If you were burning coal, you wouldn’t get sparks. Maybe they were baking bread, cornbread. They’re carrying that stack high enough to get above the wooden elevator. What the hell it could be made of to be that thin and not be braced?

I don’t understand what’s with the masonry mixer down there. If that stack, for example, was a heavy metal tube, I don’t know that you could plaster it.

The gun fired, and continuous action of many processes began in Alta, Iowa

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In this post, Charles J. Tillotson elaborates on Neil A. Lieb’s previous comments, describing the above photo from his archive. The jack rods referred to in the text are the tall, slender steel poles seen throughout the photo.  

They often say, a picture is worth a thousand words and this one fits the bill perfectly. The photo is truly an aid to describing the method of slipform construction that was used in grain elevator construction. Neil mentions the one-handed placement of the jack rod, so I’ll start with that.
 
Slipform construction is made up of many complex disciplines which have to all work together in order to provide the final poured-in-place concrete product.

As mentioned prior to this, the slipping of the formwork used in this type of construction was provided by a series of screw jacks placed apart by an engineered calculation sufficient to lift each jack’s portion of the formwork assembly.

Each screw jack was supported by a wooden, U-shaped yoke, the legs of which were attached to the vertical concrete formwork. Inserted in the top (or horizontal) portion of each yoke was a screw jack (similar to that used in jacking building foundations). A smooth one-inch jack rod was then inserted into the top head of the jack and threaded down through it until stopping at the foundation slab. 

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.

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

A series of horizontal wooden rails at about waist height (looks like a railroad track) were then built directly above the open formwork, the “ties” of which were placed at prescribed intervals and used as a template spacer for inserting the actual vertical reinforcing steel. (See the small, half-inch rebar rods extending vertically out of the open bin forms at each cross tie). The vertical rebar was staggered slightly in an alternating fashion so as to allow the half-inch horizontal rebar to be threaded through the vertical rebar. On the vertical 2x4s that are attached to the exterior side of the formwork and rise above the entire deck assembly, so-called targets placed on their tops were used in leveling the deck in order to provide a final elevator that rose plumb and straight above the foundation.

As the screw jacks were turned (each jack was turned the same amount), the foreman on deck used a leveling instrument and sighted on each target to insure that the formwork was rising true plumb and level. If any of the targets did not align with true level, the portion of the deck out of plumb was corrected by extra turns of the screw jack or jacks as necessary to bring that portion of the deck up level with the rest of the formwork. 

Not shown in the photo is the horizontal rebar that was required to form a steel reinforced grid integrally cast in the concrete to form a reinforced concrete structure. Initially, the horizontal steel was wire-tied in place to the vertical rebar prior to one side of the forms being installed.  This placement occurred only to the height of the wood bin forms. Once the form-lifting began, the horizontal steel was placed by hand by pushing and threading the rebar horizontally through the vertical rebar. Because of the vertical movement of the formwork, close attention was required as to the spacing between horizontal rebar. 

Now, try to imagine: the start gun is fired and the continuous action of the many processes begins, never to stop until the wooden forms and finished structure reaches the prescribed vertical height (some 120 feet) eight days later. Manual labor is involved in each discipline. Personnel changes occur, but each position is filled by a replacement. The gun is fired, cement is mixed and lifted to the deck of the formwork via a Georgia buggy, and the content is dumped into the open form. The pouring of the cement into the formwork is continued in a circular fashion around the entire deck until it reaches a prescribed height in the form. 

The finished elevator. Photo from the Neil A. Lieb Archive.

The finished elevator. Photo from the Neil A. Lieb Archive.

Once the cement is allowed to solidify in the forms on the foundation slab, the jacking operation begins and the formwork starts its vertical lifting and slipping process. The jacks are turned, the cement is poured, the vertical rebar and jackrods are placed and spliced, and all the while the horizontal rebar is positioned at the proper height and spacing. Pour cement, turn jacks, place rebar, check deck level, and on and on through night and day until the construction reaches final height. The most problematic aspect of this system is the placing of the horizontal steel at the correct spacing, the placement of formed openings in the bins, keeping the hoist in operation, mixing the cement, and obtaining enough set time of the cement mixture so that as the finished concrete walls do not fall apart or slough off.     

Also, hanging beneath the formwork structure is the scaffolding for the cement finishers who dutifully serve to patch and smoothly finish the concrete surfaces appearing at the bottom of the vertically slipping formwork. 

 

 

Analysis of photos from Tillotson Construction’s job in Alta, Iowa

 

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By Charles J. Tillotson with photos from the Neil A. Lieb archive

The images from the Neil A. Lieb Archive are the best historical, phase-by-phase photos that I’ve seen yet. They give the layman a good concept of what actually takes place, from start to finish, in building a grain elevator.

A few comments I might add:

The excavation for the foundation began with dynamite.

Excavating the foundation began with a bang.

Neil writes about the use of dynamite during the excavation process. Dynamite was used for foundation excavation on many a job because of the deep frost. We even used it for cutting the foundation of the reinforced concrete garage we built on the old place in Omaha. We were young ’ns then, but still got to set (light) the fuses to a few charges.

I remember getting the neighbors excited about what the hell we were doin’ now.

By the way, the garage utilized slip-form construction with steel stays instead of wood for the formwork—another of Dad’s experiments. He was interested in finding materials that could be reused over and over, rather than having to buy lumber formwork for every new job. I guess this method didn’t make a lot of sense, as he never tried it out on an elevator.

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This photo is an historical testimony as to how the so-called unskilled, common man could be taught layout along with measuring, wood cutting, and other carpentry skills. The labor used to build these forms and construct the entire grain elevator structure was obtained, for the most part, from the inhabitants of the local vicinity where the elevator was to be built. Most of the workmen had no experience whatsoever in the construction industry.

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People used to marvel at how the cement went into the top of the formwork and came out the bottom of the forms, in a set-up, semi-solid state, all occurring whilst the deck and forms continued to extend upwards, being jacked up on screw jacks. Once the slipping of the forms began, it never stopped, unless by a power outage, a severe storm, or some other interference.

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Beneath the deck and main formwork, a sub-scaffolding was constructed to provide access to the exterior face of the concrete structure, which required patching and touch-up for a final smooth finish. A rich mixture of cement, sand, and lime was used which was applied to the concrete face by hand, usually covering the entire exterior surface, removing all blemishes. The finish material was hoisted in five-gallon buckets to the finishers. These workmen traversed the scaffold of wood planking—usually two, 2 x 12s laid flat between the wooden hanger frames that attached to the formwork above. Very dangerous work without a safety net!

At the ground level, a workman on a tractor would load a Georgia buggy with cement, to be hoisted to the top and placed in the formwork. Small skip loaders, tractors with scoop-type buckets mounted on the front, were an essential tool used during construction. This included scooping up the sand, gravel, and cement to make concrete and placing them in a mixer.

Neil A. Lieb collection Once the concrete was ready for placement, the tractor scoop was filled with the cementitous mixture and transported to the side of the elevator whereby the tractor would dump its load into a Georgia buggy to be hoisted up to the deck for placement.

Because of the extensive use of the tractor, more than one would be worn out. During the extremely active 1950s, Tillotson Construction Company would purchase Ford Ferguson tractors a dozen at a time, just to keep up with the need for replacement

The logistics of material supply was always challenging for the grain elevator builder. Usually, the projects were located in very rural farmland areas, where the supply of lumber, steel, sand, gravel, cement, gasoline, and oil was miles from the site. Because the construction utilized the slip-form method, the operation never stopped once it began, making it paramount that the supply of materials be established beforehand along with a comfort level that there would be no interruption once the job started.

Neil has noted (in an as yet unpublished commentary) the mixture of the gleaming, white, finished “paint,” which wasn’t really paint at all but instead a cementitious mixture that lasted for a very long time. Some of the elevators existing today still boast the original finish. Tillotson was among the few contractors that finished out their jobs this way.

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Training the local unskilled labor in the processes of placing and wire-tying the reinforcing steel –and of pouring concrete, turning screw jacks, keeping the slip-form deck level, et cetera– were just a few of the many headaches the job superintendent had to bear during the initial start-up phases.

Charles H. Tillotson straddled the divide between wood and concrete

Charles H. Tillotson

By Ronald Ahrens

My Great-grandfather Charles H. Tillotson may have been following his trade by instinct, but he opened the way for descendants to distinguish themselves in the business of elevator construction.

I know the Tillotsons saw themselves primarily as carpenters. My Uncle Charles J. Tillotson went to work as an apprentice carpenter for Tillotson Construction, which was founded after the death of his grandfather Charles. My Uncle Michael Tillotson learned carpentry on through the family business and worked as a carpenter throughout his career. When I helped him finish concrete sidewalks on a couple of side jobs in the 1970s, he preached a gospel that carpenters could do it all, whether it be concrete or painting. And in elevator construction, it was true.

Charles H. Tillotson was born in Brunswick, Mo., in 1880. He married Rose Brennan in Riverside, Iowa.

He and my Great-grandmother Rose had an apparently cozy life in Omaha with their three grown children, Joseph, Reginald, and Mary, all of whom became involved in elevator construction. Kristen Cart’s research has found the Tillotsons listed in the 1930 census. They lived at 624 N. 41st.

A 1936 city directory listed Charles H. as president of Van Ness Construction, a company that built mills and elevators. Joseph served as secretary-treasurer and Reginald was a foreman. Mary worked as a clerk-typist at the Federal Land Bank.

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By then, Reginald was married to my grandmother, Margaret Irene McDunn Tillotson. Their firstborn Charles J., had arrived in 1935, followed the next year by my mother, Mary Catherine.

Uncle Tim Tillotson, the middle of their three sons between Charles J. and Michael (who was born in a home-built house trailer at a Smith Center, Kan., job site), says a story exchanged among the uncles was that Great-grandfather Charles H. would tell Reginald, “Put out that cigarette,” when they were working on jobs. The danger of fire was constant. How ironic, then, that Charles H. held a cigarette for his portrait.

After the death of paterfamilias Charles H., the Tillotson Construction Company was formed by Reginald, Joseph, and Mary. We would love to learn more about how this proceeded.

Meanwhile, the transition to slip-formed concrete construction was under way, with the Tillotsons’ carpentry skills being readily applied to the formwork.

Wrecking out details are provided in drawings from Tillotson records

Charles H. Tillotson

By Ronald Ahrens

The papers we received from my Uncle Tim Tillotson included not only the record of Tillotson Construction Company’s building activities, but also these pages showing details of building a wrecking-out platform as well as jack rod assemblies and formwork details. Page two is dated November 12, 1954.

A wrecking-out platform was needed as workers disassembled the formwork on the inside of the completed elevator.

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Uncle Charles Tillotson has previously written about his close call when cable clamps failed.

In that post he described a wrecking-out platform this way:

The final scaffold then becomes a square platform suspended in a round tank.

The void on each side of the scaffold is used for lowering or throwing the wood material into the tank’s dark abyss. After all the overhead wrecking has been accomplished, another team gains access to the tank’s bottom via a manhole in the side of the tank at or near ground level.

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The drawings and details presented in the notes included here are invaluable. For example: The hole in the roof is formed with a one-quart motor oil can. (“Remove can & plug hole,” the addendum reminds.)

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The handwritten note in the upper right corner of the first page says, “I put my center needle beam under the manhole then it is easy to get plank on and easy to get on scaffold. If you think this helps O.K. other wise [illegible] to a goose going south.”

“I’ll pick it up when I catch him down about Galveston,” this section concludes.

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Another note is on the quality of timbers: “I’ve been using these for 20 years if you use 3 good 2 x 6 they work fine and save over the 3 x 6 & all that steel and all you have to do is cut the ones you use in the tanks and they will work in small bins.”

We look forward to readers’ comments on the pages.

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List of Tillotson Construction supervisors includes 2 unfortunate incidents

Flagler by Gary Rich

Flagler, Colo. in 2011. Photo by Gary Rich

By Ronald Ahrens

My uncles Tim and Charles Tillotson have put their heads together and come up with a list of supervisors who directed operations on Tillotson Construction Company jobs. What follows are Uncle Tim’s notes, and we’ve done the best that we can in regard to spelling.

Glen Morrison

Francis Dawson (ranch in New Mexico connected to ours)

Doyle Elliott

Glen Casey

Jerry Grimes

Wallly Farmer (also did the house, Kelby Road)

Bill Russell (had seven [surviving] sons; some ran jobs for us; one [the eighth] was electrocuted dropping a steel measuring tape down one morning to verify height on a deck “story pole”; wind blew tape, which touched bare spot on high-tension power lines)

Jim Sheets (’bout half Native American)

Everett Glen (Chas & I concur Everett was the super on Flagler, Colo., in 1953; I had told you before that Mother found him dead in his car in the parking at the house where he was working on finish trim, cabinet work, et cetera; this unfortunate incident had to be fall or winter of ’53 after the job in the summer.)

The Vinton Street elevator was Tillotson Construction’s 1950 hometown showcase

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Story by Ronald Ahrens 

The Vinton Street elevator in Omaha was a significant job for Tillotson Construction Company, being a technical challenge to the nine-year-old outfit and representing a major emphasis in its subsequent marketing effort.

Lucky for us, much attention was paid to taking good photos of the elevator, including some early color images that include views of the construction process. These photos were in the hands of Uncle Tim Tillotson, who passed them to us for scanning. The color ones came from a viewer that was presumably shown to prospective clients.

With its headhouse accommodating three legs to lift the grain, it was tall. Exactly how tall isn’t recorded, but it probably came within sniffing distance of 200 feet. Only a few of the city’s downtown office towers surpassed its height, although they weren’t necessarily better-looking.

This terminal elevator had capacity of 382,880 bushels, and the legs handled distribution of the grain inside the main house.

Scan 5It also was a showcase that family and friends could see for themselves. Until then, Tillotson Construction had been building elevators in Texas and Oklahoma as well as some less far-flung places.

The elevator was completed in 1950 on a South Omaha greenfield site at 34th and Vinton Streets. The company’s office at 12th and Jones was only three miles away.

Another reason for its significance is that Reginald and Margaret Tillotson’s oldest son Charles went to work as an apprentice carpenter and hod carrier on the job. He helped to build several other elevators over the next few years.

With the Tillotson construction record now in hand, we present the following technical specifications without yet having achieved a full understanding of all the abbreviations and lingo.

General specifications

Total capacity: 382,880 bushels

Capacity: 38,878 bushels per foot

Reinforced concrete: 4776 cubic yards

Plain concrete (hoppers): 35.3 cubic yards

Reinforcing steel (includes jack rods): 286.5 tons

Average steel per cubic yard of reinforced concrete: 120 lb

Construction of the hoist very early in the process of building the Vinton Street elevator. Note the Georgia buggies near the formwork.

Construction of the hoist very early in the process of building the Vinton Street elevator. Note the Georgia buggies near the formwork.

Steel and Concrete

Below main slab: 20,932 lb/223 c.y.

Main slab: 66,579 lb/618 c.y.

Drawform walls: 233,927 lb/2100 c.y.

Driveway and work floor: no figure for steel/17 c.y.

Deep bin bottoms (including columns): no figure for steel/155 c.y.

O.H. bin bottoms: no figure for steel/40 c.y.

Bin root: no figure given for steel/90 c.y.

Scale floor (or garner, complete): no figure for steel/17 c.y.

Cupola (headhouse) walls: no figures

Distributor floor (cleaner floor): no figure for steel/8 c.y.

Cupola roof (gallery): no figure for steel/49 c.y.

Miscellaneous (headhouse): no figure for steel/640 c.y.

Attached driveway: driveway 416 c.y., track shed 403 c.y.

Construction Details

Main slab dimensions: 58 x 119.5 feet

Main slab area (outside on ground): 6690 sq ft

Weight reinforced (total) concrete  at 4000 lb per c.y., plus steel: 9838 tons

Weight plain concrete (hoppers, 4000 lb per c.y.): 70.6 tons

Weight hopper fill sand at 3000 lb per c.y.: 439.8 tons

Weight of grain at 60 lb per bushel: 11,490 tons

Weight of structural steel and machinery: 100 tons

Gross weight loaded: 21,938 tons

This extreme view shows the elevator before painting. The individual pours can be seen in the drawform walls of the bins. Note the man leaning out of the window opening on the left.

This extreme view shows the elevator before painting. The individual pours can be seen in the drawform walls of the bins. Click on the photo to enlarge the image, and you’ll note the man leaning out of the window opening on the left.

Bearing pressure: 3.28 tons per sq ft

Main slab thickness: 30 in

Main slab steel: 1 in □ at 7 in o.c.

Tank steel at bottom (round tanks): ⅝ in ⌀ at 8 in o.c.

Lineal feet of drawform walls: 975 ft

Height of drawform walls: 120 ft

Pit depth below main slab: 20 ft, 9 in

Cupola (headhouse) dimensions outside (length x width x height): 24 ft x 52 ft x no figure recorded

Machinery Details

Boot pulley: 72 in x 28 in x 3 7/16 in

Head pulley: 72 in x 28 in x 5 15/16 in

RPM head pulley 39 rpm

Belt: leg 26 in x 8-ply, conx 36 in x 4 ply

Cups: 21 x 7 in cal. at 9 in o.c. stag.

Head drive: Link belt, 100 hp

Theoretical leg capacity (Cub manufacturer rating): 17,400 bushels per hour

Actual leg capacity (80 percent of theoretical): 13,900 bushels per hour

HP required for leg (based on above actual plus 15 percent for motor): 89.8 hp

My grandfather used one of the color images from Vinton Street on its business card.

My grandfather used one of the color images from Vinton Street on its business card.

Man lift: 2 – 1.5 hp

Load out scale: Two 2500-bushel hop.

Load out spout: 15-inch diameter

Truck lift: Ehr. semi fans w. col.

Dust collector system: on legs

Cupola spouting: Trolly spouts

Driveway doors: Johnson O.H. rolling

Conveyor: Two 36-in belts and two 30-in belts

 

Also Built

Track shed

Truck shed

Office

Truck scale