318 



THE GARDEN AND FIELD. 



December, l9l3 



Concrete Silos. 



By J. Wilson, Silo Builder, Jour- 

 nal of Agriculture, Victoria. 



The advantage derived from the 

 construction of silos by using 

 concrete bricks made from the 

 material found on most farms, 

 namely, gravel and sand, with the 

 addition of a proportion of cement 

 (six of sand to one of cement), 

 is steadily being recognised. The 

 silo so built is fireproof, white ant 

 and mouse proof, as well as being 

 durabfe. The proportion of ce- 

 ment used is so small that it is 

 hardly noticeable in the matter of 

 cost, onlv sixteen casks of cement 

 are used to make the bricks and 

 set them in a 70-ton silo. Far- 

 mers who elect to build silos or 

 farm' buildino-s generallv for them- 

 selves with the aid of farm labour 

 can now do so wath a brickmak- 

 ing machine and the use of aver- 

 age intelligence. The necessary 

 material, sand and gravel, or sand, 

 is usuallv to be found close at 

 hand. The sand should be sharp, 

 and washed clean, as both clay 

 and loam are drawbacks, particu- 

 larlv the former. An up-to-date 

 m'achine made entirely of steel can 

 be had for a nominal sum. The 

 machine makes a hollow brick 24 

 ins. b" 6 ins bv (-N, ins., and is 

 lifted from the brick, thus nre- 

 ventiuT anv T^'^s^i'^lilv of the block 

 becoming- cracked or strained. The 

 weirnht of a single brick is about 

 yo Itis., and considerable care and 

 thoueht has been exr)ended over 

 the construction of the machine ; 

 its usefulness for silos or buildings 

 is fullv as.sured. 



To build a 70-ton silo, 850 

 blocks of the si/e mentioned are 

 reouired, and one man, with the 

 assistance of a lad, can make therrf 

 in a week, and the buildine should 

 not occtipv more than ten to 

 twcl\-e davs to erect. The bricks 

 must be pronerlv cured before lay- 

 ine ; this is accomnlisherl bv 

 .sprinklinfr thf-m wi+h water night 

 and morninp- for a fortniplit, so as 

 to prevent them from drvnuf too 

 quicklv. In buildine the blocks 

 are set in cemMit mortar of a 

 mixture made of four parts of sand 

 to one part cement in the sarne 

 manner as ordinary bricks. It is 

 advisable 'not to mix more mortar 

 than can be u.sed in half an hour, 

 as set or hardened cement mortar 

 is quite useless. To insure suc- 

 cess, the initial set should not be 

 disturbed. 



— Foundations. — 



Level a srite for a diameter of 

 t6 feet, fix a centre point by plac- 



ing a 2in. pipe firmly in the ground 

 so as to receive a 2-in. pole ; from 

 this centre attach a piece of quar- 

 tering, 7ft. 4in. long, to act as a 

 trammel which will describe a cir- 

 cle having a diameter of 14ft. Sin. 

 inside measurement. Care should 

 be taken to fix the pole plumb so 

 as to obtain an accurate circle. 

 Cut out a trench 6 inches deep and 

 12 inches wide, the bottom, to be 

 level. A double wall is laid in 

 the trench for the first course, and 

 then single walls to the top. ' 



The blocks break joints at V2 



inches in succeeding courses, which 



allow the hollows in the bricks 

 to come over each other. 



— Reinforcing. — 



During the course of construc- 

 tion the walls should be reinforced 

 bv laying on the top of each course 

 ordinary fencing wire (any old wire 

 lying about the farm will answer 

 the purpose), clipped together at 

 joints, and built in with the 

 blocks. Three rows 'of wire to 

 each course for the first 4 feet, and 

 for the remainder two rows of 

 wire. The height of a 70-ton silo 

 is 21 feet, and inside diameter 14 

 ft. 8 in., and requires '850 bricks, 

 each 24 inches long, of this num- 

 ber 45 would be required to form 

 the footing course. Port holes, or 

 doors, are iormed in the following 

 manner : — The first or bottom dooT 

 commences six courses from the 

 ground, one brick being left out 

 for four courses ; there are thre's 

 such doors to a silo, allowing six 

 cour.ses between each door, size of 

 opening will be 2ft. by 2ft. Form 

 the doors of galvanized iron, 24 

 gauge, cut -^ft. by 2ft. 6in., and 

 nailed to three strips of ym.. by 

 I'^in. hardwood 2 feet long. Door 

 frames are built of 6in. bv i/^in. 

 hardwood, and checked out I'j 

 inches to receive ledgers of doors. 



The inside face should be bagged 

 smoothly, so as to be free of 

 mortar projectiotis, and the joints 

 of exterior struck smoothl-- with 

 a trowel. 



Build in on the top course of 

 bricks eight bolts, each To'/in. by 

 ''^in. long, for bolting down the 

 plates of the roof, four plates of 

 4in. by 2in. are used, and the 

 purlins are Propped up with 4in. 

 by 2in. studs, bolted to the plates 

 at the bottom, and halved out 

 2 inches at the top, to receive pur. 

 lins. Fix two braces 3in. by 'I'^in. 

 from centre studs to ridee pur- 

 lins ; two purlins are used to fo'x-m 

 ridce. All timber used is of hard- 

 wood. Cover with corrugated 

 iron, 9ft. .sheets, and fasten with 



spring head nails, nailing the iron 

 every second corrugation. The 

 concrete silo is one of the types 

 erected for farmers, on terms, by 

 the Department. Application forms 

 for the construction can be ob- 

 tained from the Department of 

 Agriculture, ■ Treasury Buildings, 

 MelV)ourne, togethe'r with particu- 

 lars of the general conditions un- 

 der which the silo is erected. The 

 cost of erecting a 70-ton concrete 

 silo complete, with elevator, is 

 £55, subject to slight variation.'on 

 account of distance from Mel- 

 bourne and cost of cement. 



— Material Required for a 70-ton 



Concrete Silo. — 



Hardwood, 4. in. x 2 in., six 18 

 feet, three '16 feet, purlins plates 

 and studs. 



Hardwood, 6 in. by I'j in. three 

 9 feet, door frames. 



Hardwood, 3 in. by I'j in., two 

 i'8 feet, braces for roof. 



Galvanized corrugated iron, 26 

 gauge, 9 feet, eighteen sheets. 



Galvanised plain iron, 24 gauge, 

 72 in. by 36 in., three sheets. 



Galvanized ridging, 26 gauge, 16 

 inches, 18 feet. 



Spring head nails, 2'/^ inches, 3 



tt)S. 



Wire nails, 3 inches, 5 lbs. 



Cement, sixteen casks. 



Sand, 16 cubic yards. 



Bolts, nuts, and washers, eight 

 TO''j in. X % in., two 6^ in. x \ in., 

 ten 4'2 in. x y<^ in. 



— Material for 30ft. Elevator. — 



White deal, 6 in. x % in., T. and 

 G., nineteen 20 feet. 



White deal, 6 in. x % in., T. and 

 G., four 15 feet. 



Oregon, 6 in. x 1% in., one 8 feet. 



Chain, 60 feet, i 9-16 pitch. No. 

 45 link. 



Thirtv Oretjon slats and attach- 

 ments for No. 4,=, link. 



One 8-inch dianTeter sprocket 

 wheel, ifv teeth, i 9-16 inches pitch. 



One 8-inch diameter by ii^^nch 

 I)unev. 



Two adjustable bearings. 



One 22 teeth, id'^-inch diameter, 

 sprocket wheel for No. 52 link, i'^ 

 inch pitch. 



One TO teeth 5-inch diameter 

 sprocket wheel for No. 52 link, i)^ 

 inch pftch. 



14-ft. chain r^-inch pitch, No. 52 

 link. 



Right 2'5finch by ^-inch bolts, 

 nuts, and washers. 



