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

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.

DSC_0547

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.

DSC_0563

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

DSC_0541

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)

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