Photos contributed by Neil A. Lieb
Of the slew of elevators Tillotson Construction Company put up in 1950, the one at Alta, Iowa, could have been considered a typical job, although the photo above shows that a sign company must have gone to work sinking anchors in the headhouse for the raised lettering. Built in the small Buena Vista County town that sits at the highest point on the Chicago-Illinois Railroad in its crossing of the Hawkeye State, the elevator followed Tillotson’s established Palmer Plan, with eight tanks of 18 feet in diameter rising to 115 feet in height. There was a 13-foot-wide driveway passing through the house in an opening 15 feet high under four split bins. An additional note about the Palmer plan says, “Extra dist @ Cupola and on Cleaner Floor,” and we take the abbreviation to mean distribution.
Formwork as the Alta Cooperative’s elevator rises in a continuous pour. Note the driveway door.
Here is the full list of specifications:
Capacity per Plans (with Pack) 246,070 bushels
Capacity per foot of height 2640 bushels
Reinforced concrete/plans (Total) 2082 cubic yards
Plain concrete (hoppers) 49.6 cubic yards
Reinforcing steel/Plans (includes jack rods) 112.4 tons
Average steel per cubic yard of reinforced concrete 107/96 pounds
Steel & reinforced concrete itemized per plans
Below main slab 9419 lb/91 cu yd
Main slab 32,077 lb/272 cu yd
Drawform walls 142,070 lb/1424 cu yd
Work & driveway floor (including columns) 1485 lb/30 cu yd
Deep bin bottoms 6682 lb/47 cu yd
Overhead bin bottoms 7929 lb/40 cu yd
Bin roof (corner) 10150 lb/51 cu yd
Scale floor (complete) none
Cupola walls 9655 lb/88 cu yd
Distributor floor 1912 lb/10 cu yd
Cupola roof 2753 lb/15 cu yd
Miscellaneous (boot, leg, head, track sink, steps) 2560 lb/13 cu yd (a note here in the plans says “Cleaner floor”)
Elevator construction continued around the clock in a spectacle that must have awed the community.
Main slab dimensions (Drive length first dimen.) 60 x 73.5 feet
Main slab area (actual outside on ground) 4101 sqare feet
Weight of reinforced (total) concrete (4000#/cu yd + steel) 4276 tons
Weight of plan concrete (hoppers 4000#/cu yd) 99 tons
Weight hopper fill sand (3000#/cu yd) 708 tons
Weight of grain (at 60# per bushel) 7380 tons
Weight of structural steel & machinery 20 tons
Gross weight loaded 12,483 tons
Bearing pressure 3.04 tons per sq ft
Main slab thickness 24 inches
Main slab steel (bent) 1 in diameter at 7 inch o.c.
Tank steel at bottom (round tanks) 5/8 inch diameter at 6 inch o.c.
Lineal feet of drawform walls 762 feet including exterior
Height of drawform walls 115 feet
Pit depth below main slab 15 feet 0 inches
Cupola dimensions (W x L x Ht.) 23 x 61.5 x 39 feet
Pulley centers 161 feet
Number of legs 1
Distributor floor Yes
Track sink Yes
Full basement Yes
Electrical room Yes
Driveway width–clear 13 feet
Dump grate size 3 – 9 x 6 feet
Columns under tanks size 20 inches square
Boot — leg & head Concrete
Boot pulley 72 x 14 x 2 3/16 inches
Head pulley 72 x 14 x 3 15/16 inches
R.P.M. head pulley 42 rpm
Belt 14 inch 6 ply Calumet
Cups 12 x 6 inch at 8 inch o.c. Howell
Head drive 40 horsepower
Theoretical leg capacity (cup manufacturer rating) 8440 bushels per hour
Actual leg capacity (80 percent of theoretical) 6750 bushels per hour
The finished elevator, before whitewashing and installation of the headhouse windows.
Horsepower required for leg (based on above actual capacity plus 15 percent for motor) 33 hp
Man lift 1.5 horsepower electric
Load out scale Two 25 bushel Rich.
Load out spout 10.75 inch W.C.
Cupola spouting 10-inch diameter 14 gauge
Truck lift 7.5 horsepower Ehr
Dust collector system Fan → Dust bin
Driveway doors Two overhead rolling
Conveyor 14-inch R.H. 3 hp.