REINFORCED 
 
 CONCRETE 
 
 CODE 
 
 CITY OF COLUMBUS 
 OHIO 
 
 DEPARTMENT OF 
 BUILDINGS 
 
Reinforced 
 Concrete Code 
 
 * 
 
 AN ORDINANCE No. 27098 
 
 To define 'and describe the term and meaning 
 of reinforced concrete construction and to 
 regulate the manner of its use in building 
 operations. 
 
 Be it Ordained by the Council of the City of 
 Columbus, State of Ohio: 
 
 Section 1. Definition. By the term Rein- 
 forced Concrete in these regulations is meant 
 an approved structural combination of concrete 
 and steel, so arranged that the steel resists all 
 the tensile stresses and may aid the concrete in 
 resisting shear and compression. No system 
 of reinforced concrete design shall be used 
 which is not capable of design and investiga- 
 tion according to the best engineering practice, 
 and the principles laid down in this code. 
 
 Sec. 2. Requirements for Permit. Before a 
 permit to erect any reinforced concrete struc- 
 ture is granted, complete plans and specifica- 
 tions showing all details of construction, the 
 size and position of all reinforcing members and 
 the composition of the concrete shall be sub- 
 mitted to the Department of Buildings. The 
 Department of Buildings reserves the right to 
 demand that the owner, architect or engineer 
 submit certified copies of all computations or 
 stress sheets for examination upon application 
 for a building permit. 
 
 Permission to erect any reinforced concrete 
 
 3 
 
structure does not in any way approve the con- 
 struction until after tests have been made of 
 the actual construction to the satisfaction of 
 the Department of Buildings. 
 
 Sec. 3. Unit Stresses. The following unit 
 stresses shall not be exceeded: 
 
 Medium steel, 16,000 lbs. per sq. in. 
 
 High carbon steel, 18,000 lbs. per sq. in. 
 
 Steel to resist diagnoal tension, 12,000 lbs. 
 per sq. in. 
 
 Concrete, extreme fiber in compression, 700 
 lbs. per sq. in. 
 
 Bond stresses for plain round bars, 70 lbs. per 
 sq. in. 
 
 Bond stresses for twisted bars or deformed 
 bars, 100 lbs. per sq. in. 
 
 Concrete in shear, 50 lbs. per^q. in. 
 
 Sec. 4. Assumptions. The following as- 
 sumptions shall be made as a basis for the cal- 
 culation of girders, beams and slabs : 
 
 (a) The stress strain curve of concrete in 
 compression is a straight line. 
 
 (b) The modulus of elasticity of concrete 
 remains constant within the limits of unit 
 working stresses specified in this ordinance. 
 
 (c) The adhesion between concrete and steel 
 is sufficient to make the two materials act 
 together. 
 
 (d) Concrete has no value in tension. 
 
 (e) The ratio of the modulus of elasticity of 
 steel to the modulus of elasticity of concrete 
 is 15. 
 
 Sec. 5. Slabs, Beams and Girders. Slabs, 
 beams and girders with uniform distribution of 
 load shall be calculated as follows: When sim- 
 ply supported the moment equals WL/8; when 
 continuous over one support the moments shall 
 
 4 
 
be considered as WL/10 at center and WL/8 
 over intermediate support; when continuous 
 over two or more supports with equal or ap- 
 proximately equal spans, the moments shall be 
 considered as WL/12 at center and over sup- 
 ports of intermediate spans, and WL/10 at cen- 
 ter of end span and over second support; where 
 “W”=total load and “L”=span in feet. 
 
 In continuous slabs, beams and girders, with 
 uniform distribution of load, continuity rein- 
 forcing shall extend over and beyond supports 
 at least one-fourth (J4) of the adjoining span. 
 
 Concentrated loads shall be computed accord- 
 ing to accepted theory, and in the case of con- 
 tinuous spans proper provisions shall be made 
 for continuity. 
 
 For slabs, beams and girders the span shall 
 be taken as the distance from center to center 
 of supports, but need not exceed the clear 
 span plus the depth of slab, beam or girder. 
 
 "Sec. 6. Tee-Beams. Where beams are 
 made monolithic with the floor slab, with the 
 slab reinforcing at right angles to the beam, 
 the slab may be considered as acting in flex- 
 ture with the beam, provided the width of 
 slab so considered be governed by the shear- 
 ing resistance between the slab and beam, but 
 be limited on either side of the beam to 1/6 
 of the span of the beam between supports and 
 also limited on either side of the beam to five 
 (5) times the thickness of the slab. In case 
 the reinforcing is not at right angles to the 
 beam, the portion of the slab so considered 
 shall be limited on either side of the beam 
 to three (3) times the thickness of the slab. 
 In no case shall the total width of flange so 
 taken exceed the distance center to center , of 
 beams. 
 
 No part of the slab shall be considered as a 
 
 5 
 
portion of the beam unless the slab and beam 
 are cast at the same time. 
 
 Where reinforced concrete girders support 
 reinforced concrete beams, the portion of the 
 floor slab acting as flange to the girder must 
 be reinforced with rods near the top, at right 
 angles to the girder, to enable it to transmit 
 local loads directly to the girder and not 
 through the beams. 
 
 In tee-beams construction the bottom of the 
 web over continuous supports shall be pro- 
 vided with haunches, or be reinforced with 
 sufficient steel in compression, to reduce the 
 stress on the concrete to within ten per cent 
 of that allowed at the center of the span. This 
 steel shall project at least twenty-four inches 
 on each side of supports and the unit com- 
 pressive stress in the steel shall not exceed 
 fifteen (15) times the unit compressive stress 
 in the concrete at the same distance from the 
 neutral axis. 
 
 Sec. 7. Square and Rectangular Slabs. For 
 
 square slabs reinforced in both directions the 
 moments for each set of reinforcing in the 
 center half of the slab shall be taken not less 
 than WL 2 /16 where the slab under considera- 
 tion is not continuous; WL 2 /20 where the 
 slab under consideration is continuous over 
 one support, and WL 2 /24 at center and over 
 supports where the slab is continuous over 
 both supports; where “W”=the load per 
 square foot and “L”=side of square in feet. 
 The steel in the remaining quarters may be 
 proportioned by using one-half of the amount 
 used in the middle half. 
 
 For rectangular slabs, with equal spacing of 
 reinforcing in each direction, the transverse 
 reinforcing shall be proportioned to carry the 
 
 6 
 
 j 
 
amount of load given by the following 
 formula : 
 
 Wa 4 
 
 w= 
 
 a 4 +b 4 
 
 Where “w”==load per square foot carried by 
 the transverse reinforcing. 
 
 “W”=total load per square foot of slab. 
 
 “a”=length of slab and 
 
 “b”=breadth of slab. 
 
 The moments in the central half of the slab 
 for the transverse reinforcement shall be not 
 less than wa 2 /8 where the slab is not contin- 
 uous, wa 2 /10 where the slab is continuous 
 over one support, and wa 2 /12 at center and 
 over supports where the slab is continuous 
 over both supports. The steel in the remain- 
 ing quarters may be proportioned by using 
 one-half (J4) the amount used in the middle 
 half. Where the length of a rectangular slab 
 exceeds one and one-half (1J4) times the 
 breadth, the load shall be assumed to all be 
 carried by the transverse reinforcement. 
 
 The amount of load carried to the side beams 
 for square and rectangular slabs shall be taken 
 according to the above assumptions and mo- 
 ments, as derived by the assumption of uniform 
 distribution of load, shall be increased twenty- 
 five (25) per cent. 
 
 Sec. 8. Minimum Thickness of Slabs. Re- 
 inforced concrete slabs shall not be less than 
 four (4) inches thick for floors, and three and 
 one-half (3/4) inches for roofs in beams and 
 girder construction, except in spans of six feet 
 or under, in which case the above thicknesses 
 may be decreased one-half (J4) inch, provided 
 the unit stresses as herein given are not efcc- 
 
 7 
 
ceeded. Slabs shall not be less than two (2) 
 inches thick, with reinforcing at right angles 
 to the beam, for floors using beams spaced 
 close together and separated by hollow tile or 
 other centering or fillers satisfactory to the 
 Inspector of Buildings. 
 
 Sec. 9. Reinforced Terra Cotta Hollow Tile. 
 
 (a) By reinforced terra cotta tile is meant a 
 system of hollow burned clay tile in combina- 
 tion with reinforced concrete, in which combi- 
 nation the hollow tile may be used to resist 
 compressive and shearing stresses, subject to 
 the following provisions : 
 
 The provisions relating to reinforced con- 
 crete construction shall hold as far as appli- 
 cable to this system. 
 
 All tile to be hard burned terra cotta tile of 
 uniform quality, deeply scored, free from 
 shrinkage cracks, with true beds, and having 
 an ultimate compressive strength of 4000 lbs. 
 per square inch of the net area of surface 
 tested. 
 
 The following unit stresses and values shall 
 not be exceeded. Compression, extreme fiber 
 stress on tile 500 pounds per square inch. 
 Shearing stress on tile 200 pounds per square 
 inch. Adhesion between tile and 1:2; 4 con- 
 crete to 1 :3 mortar, 40- pounds per square inch. 
 
 Ratio of modulus of elasticity of steel to that 
 of tile with cement mortar joints, 10. 
 
 (b) Workmanship. The hollow tile shall 
 be thoroughly drenched with water at the time 
 the concrete is poured. The lines of tile shall 
 be true and the joints between tiles shall be 
 staggered. 
 
 Sec. 10. Girderless Floor. By girderless 
 floors is meant a type of reinforced concrete 
 construction in which the columns are pro- 
 
 8 
 
vided with flaring heads and the loads are 
 carried directly to the columns by the slab and 
 not through beams and girders. • 
 
 The bending moment at the center of the 
 slab shall not be less than WL/30 where 
 “W”=total load on panel and “L”=length in 
 feet of the side of a square panel and of the 
 side of an equivalent square in rectangular 
 panels. This length shall be taken center to 
 center of columns. The steel to resist this 
 moment shall be divided into four bands, two 
 in cross and two in diagonal direction over the 
 column head. 
 
 Each band of steel shall be approximately 
 7/16 L in width and the total amount of steel 
 in any one band shall not exceed .30 of 1 per 
 cent for high carbon and .36 of 1 per cent for 
 medium steel. In determining the percentage 
 of steel, the width of concrete band so consid- 
 ered shall not exceed the width of band of 
 steel plus twice the thickness of the slab. 
 
 All splices shall be made at the column 
 heads and the amount of lap of each bar shall 
 be approximately one-fourth L (J^L). At 
 least 50 per cent of all the bars shall be spliced 
 over each column. In this construction provi- 
 sion shall be made to take care of the circum- 
 ferential stresses. Proper provisions shall be 
 made for resisting the* shear at the capital and 
 for holding the steel in the proper position over 
 the column head. 
 
 The diameter of the column head shall never 
 be less than .25L and its profile shall not fall 
 inside of a line drawn from its periphery to the 
 edge of the column and making an angle of 
 45 degrees with the vertical. The spiral rein- 
 forcing of the column shall extend into the 
 
 9 
 
capital approximately to the under side of the 
 slab. 
 
 The minimum thickness of the slab shall be 
 seven (7) inches for floors and six and one- 
 half (6 J4) inches for roofs. 
 
 In end panels or wall panels, in which wall 
 columns of reinforced concrete “with flaring 
 heads are omitted an allowance of ten (10) 
 per cent shall be made for increased moments. 
 Wall columns shall be designed to carry one- 
 half the panel load and such other loads as 
 may come upon it, and if necessary the col- 
 umns shall be designed for eccentric stresses. 
 The wall beams shall be designed for one-third 
 the panel load plus any other loads which may 
 come upon them. 
 
 Sec. 11. Web Stresses. Shear on concrete 
 shall not exceed one hundred and twenty (120) 
 pounds per square inch, but where said shear 
 exceeds fifty (50) pounds per square inch, web 
 reinforcement of approved design shall be used. 
 The reinforcement shall be designed to take all 
 web stresses in excess of fifty (50) pounds per 
 square inch, without exceeding the unit stresses 
 hereinbefore given, and must be so spaced as 
 to intersect any 45 degree line of rupture from 
 the neutral axis to the center of the steel. 
 Where unattached stirrups are used, they shall 
 pass under the main reinforcing bars. At- 
 tached stirrups shall have connections of suf- 
 ficient strength to develop the elastic limit of 
 the steel without slipping along or shearing 
 from the main bars. All web reinforceing 
 shall be provided with sufficient anchorage 
 above the neutral axis to develop the safe 
 strength of the member without exceeding the 
 bond stresses hereinbefore given. In comput- 
 ing the intensity of the vertical shear only the 
 area of the web between the center of grav- 
 
 10 
 
ity of the steel and the center of compression 
 of the concrete shall be considered as effective. 
 
 Sec. 12. Protection Against Fire and Cor- 
 rosion. All reinforcing steel shall be protected 
 by concrete of the following minimum thick- 
 ness : Two (2) inches in columns, one and one- 
 half (1J4) inches for beams and girders, and 
 three-fourths ($4) inches in slabs. 
 
 Sec. 13. Reinforced Concrete Columns. 
 
 Reinforced concrete columns shall not exceed 
 in length fifteen (15) times the least diameter 
 of the column, including the reinforcement, and 
 where such ratio is more than twelve (12) 
 times, the stresses shall be reduced in accord- 
 ance with the best engineering practice. In 
 computing the strength of columns only the 
 area within the limits of the ties, bands, hoop- 
 ing or spirals shall be considered as effective 
 area. The concrete which must in all cases 
 be provided outside of the ties, bands, hooping 
 or spirals as provided in Section 12, shall be 
 considered only as protection against fire and 
 corrosion. No reinforced concrete column 
 shall be used whose least side or diameter, 
 including the protection against fire and corro- 
 sion, is less than twelve (12) inches. 
 
 Wall columns and other columns subject to 
 eccentric loads of and indeterminate amount 
 shall have the stresses, as hereinbefore given, 
 reduced by twenty (20) per cent. Eccentric 
 loads of determinate amount shall be computed 
 according to accepted theory, but in no case 
 shall the sum of the stresses due to direct and 
 eccentric loads exceed the maximum stresses 
 hereinafter given for each type of column. 
 
 Sec. 14. Square Core Columns. In the 
 
 square core type of columns, where four rods 
 are used, and the minimum area of each rod 
 
 11 
 
is not less than .4418 of a square inch, and the 
 total area of the rods is not less than one-half 
 (y 2 ) and not more than four (4) per cent of 
 the required area of the column, and the max- 
 imum tie spacing does not exceed twelve (12) 
 inches, and in no case more than one-half the 
 distance between two of the vertical rods, and 
 the minimum area of the ties is at least .0625 
 of a square inch, the following values shall not 
 be exceeded: 
 
 7000 pounds per square inch on the vertical 
 steel. 
 
 500 pounds per square inch on the concrete. 
 
 In the square core type of column, where 
 eight rods are used and the minimum area of 
 each rod is not less than .4418 of a square inch, 
 and the total area of the vertical rods is not 
 less than one-half (^) of one per cent and not 
 more than fiv'e (5) per ‘cent of the required 
 area of the column, and the maximum tie spac- 
 ing does not exceed twelve (12) inches and in 
 no case more than seven (7) times the diam- 
 eter of the vertical rods, and the minimum 
 area of the ties is at least .0625 of a square inch, 
 and two sets of ties are used, one in the form 
 of a square inscribed within the outer tie; and 
 the ends of the ties secured in such a manner 
 as will fully develop the elastic limit of the 
 ties; the following values shall not be ex- 
 ceeded : 
 
 9000 pounds per square inch on the vertical 
 steel. 
 
 600 pounds per square inch on the concrete. 
 
 Sec. 15. Round Core Columns. For round 
 core columns vertically reinforced and hooped 
 with circular bands or spirals, the vertical rods 
 shall not be less than four (4) in number, nor 
 the area of the cross section of each rod less 
 
 12 
 
than .4418 of a square inch, nor the maximum 
 spacing of the verticals more than twelve and 
 one-half (12 1 / 2 ) inches measured on the cir- 
 cumference of the spiral, the percentage of 
 spiral hooping shall not be less than one-half 
 of one per cent and not more than one and one- 
 half (1 1 / 2 ) per cent of the area within the 
 hooping, the spacing of the spirals, if such are 
 used, shall not exceed one-seventh (1/7) of the 
 diameter of the core and in no case more than 
 three (3) inches. Provided, however, that in 
 cases where properly welded bars are used and 
 there are enough vertical rods of the proper 
 area to give the same restraint as a grill, the 
 spacing of the bands shall not exceed, for the 
 values hereinafter given, seven (7) times the 
 diameter of one such vertical rods. 
 
 The following values shall not be exceeded 
 for either of the foregoing conditions : 
 
 10,000 pounds per square inch on the vertical 
 steel. 
 
 700 ponds per square inch on the concrete. 
 
 10,000 pounds per square inch on 2.4 times 
 the volume of the spirals considered as imag- 
 inary verticals, provided that the spirals are 
 continuous, machine made, provided with ac- 
 curate spacers and secured at every intersec- 
 tion. 
 
 Provided, however, that if wire hooping is 
 used not less than five-sixteenth (5/16) of an 
 inch in diameter (of 80,000 pounds ultimate 
 strength and 50,000 pounds elastic limit) an 
 allowance of twelve thousand pounds per 
 square inch may be used for hooping, provided 
 that whenever such value is allowed, said 
 spirals shall be continuous, machine made, and 
 provided with accurate spacers and secured at 
 every intersection. 
 
 13 
 
Sec. 16. Column Splices. All vertical re- 
 inforcing in columns shall be spliced in such 
 manner as will transmit the stresses for which 
 it is designed. Sharp bends in the steel shall 
 be avoided. The splicing of verticals having 
 an area of less than one and one-fourth (1*4) 
 square inches may be done by -lapping, the 
 lapped bars to be wired securely to each other. 
 Verticals having an area in excess of one and 
 one-fourth square inches shall be spliced by 
 putting the bars squarely one over the other, 
 and tying the same together by some mechan- 
 ical means that will not utilize the adhesive 
 strength oT the concrete. All splices shall 
 occur only at floors or some other means of 
 lateral support. 
 
 Sec. 17. Tension in Columns. In tall nar- 
 row buildings special provisions shall be made 
 for tension in columns. 
 
 Sec. 18. Additional Stories. Where addi- 
 tional stories are to be added to work over 
 two years old, the strength of the concrete in 
 the existing columns may be taken fifteen (15) 
 per cent higher, than the values herein 
 specified. 
 
 Sec. 19. Footings. Footings for walls and 
 columns may be constructed of reinforced con- 
 crete, providing the working stresses, as given 
 in this code, for concrete and steel are not 
 exceeded, and the steel is protected by at least 
 three (3) inches of concrete. 
 
 The vertical rods in reinforced concrete col- 
 umns shall be anchored to the footings by 
 anchor bars or other means satisfactory to the 
 Inspector of Buildings. 
 
 Sec. 20. Reinforced Concrete Curtain Walls. 
 
 Exterior and interior walls of reinforced con- 
 
 14 
 
crete shall be not less than eight (8) inches 
 thick and reinforced with not less than three- 
 tenths (3/10) of one per cent of steel in each 
 direction, vertically and horizontally. Rods 
 shall be spaced not more than twelve (12) 
 inches on centers and shall be wired to each 
 other at each intersection. 
 
 Sec. 21. Cement. Only Portland cement 
 shall be used which conforms to the standard 
 specifications of the Society for testing ma- 
 terials. All cement shall be tested in lots of 
 not more than one carload, and the Department 
 of Buildings may at any time demand that cer- 
 tified copies of all test records be submitted 
 for examination. 
 
 The minimum requirements for tensile 
 strength for briquette one (1) inch square in 
 
 section shall be : 
 
 NEAT CEMENT. 
 
 24 hours in moist air 175 pounds 
 
 7 days (one day in air, six in 
 
 water) 500 pounds 
 
 28 days (one day in air, twenty- 
 
 seven in water) 600 pounds 
 
 ONE PART CEMENT, THREE PARTS 
 
 SAND. 
 
 7 days (one day in air, six in 
 
 water) 175 pounds 
 
 28 days (one day in air, twenty- 
 
 seven in water) 275 pounds 
 
 Sec. 22. Sand. Fine aggregate shall con- 
 sist of a mixture of fine and coarse grains of 
 clean, natural sand, screened to pass a one- 
 fourth inch screen, with the coarse grains pre- 
 dominating. Sand shall be composed of hafrd 
 
 15 
 
silicious particles, free from all decomposed 
 materials, loam or other deleterious matter. 
 
 Sec. 23. Aggregate. Coarse aggregate 
 shall consist of crushed stone or washed gravel. 
 It shall pass through a one (1) inch screen and 
 be retained on a one-fourth {%.) inch screen, 
 preferably graded from small to large particles. 
 Crushed stone shall be reasonably free from 
 crusher dust. The particles composing the 
 aggregate shall be clean, hard, durable and free 
 from all decomposed materials, loam or other 
 deleterious matter. 
 
 Sec. 24. Proportions for Mixing Reinforced 
 Concrete. Reinforced concrete shall consist of 
 a mixture of one part Portland cement to not 
 more than four (4) parts aggregate fine and 
 coarse either in proportion of one part cement 
 to two parts sand and four parts aggregate, or 
 in such proportion that all voids in the aggre- 
 gate shall be properly filled. 
 
 Mixing shall be done by approved batch 
 mixer, unless the conditions of the work would 
 make hand mixing preferable ; hand mixing 
 shall be done only under the approval of the 
 Department of Buildings. Enough water shall 
 be added to the mixture to make it a plastic 
 mass capable of being rammed into all parts 
 of the mould and around all reinforcing mem- 
 bers. In all mixing the separate ingredients 
 shall be measured and thoroughly mixed to a 
 uniform color, appearance and consistency be- 
 fore placing. Thirty days after mixing, the 
 concrete shall develop a compressive strength 
 of 2000 pounds per square inch by testing a 
 six-inch cube. 
 
 Sec. 25. Bending and Elongation of Steel. 
 
 The reinforcing steel used in reinforced con- 
 crete construction shall conform to the follow- 
 ing requirements : 
 
 16 
 
The Inspector of Buildings may require cer- 
 tified tests of each size of bar used in the con- 
 struction, said test to be acceptable for not 
 more than ten tons of material. 
 
 The tests for bending may be made on the 
 ground under the supervision of the Inspector 
 of Buildings or his authorized assistant. 
 
 17 
 
Sec. 26. Placing Concrete and Steel. All 
 
 reinforcement shall be free from paint, loose 
 rust, scale or coating of any character that 
 would tend to destroy the bond. Steel must 
 be accurately located and secured against dis- 
 placement before concrete is poured around 
 it. All concrete shall be tamped in place 
 within* one-half (J4) hour after mixing, and 
 shall be conveyed in place in such a manner 
 that no appreciable separation of the ingredi- 
 ents occurs. Concrete must be worked con- 
 tinuously with suitable tools as it is put in 
 place, and in warm weather must be kept moist 
 for at least seven (7) consecutive days after 
 pouring. Work must be laid out so that par- 
 tially set concrete will not be subjected to 
 shocks from handling or wheeling materials 
 over it. 
 
 Where it is not possible to cast the entire 
 structure in one operation the work shall be 
 stopped ; for columns, at the under side of the 
 girders; for girders, at a point midway be- 
 tween supports unless a beam should occur 
 at this point, in which case the joint should 
 be offset a distance equal to twice the width 
 of the beam; for slabs and beams, at the cen- 
 ter of the span. Under no circumstances shall 
 a joint be made where high present or future 
 shearing stresses may occur. The plane of all 
 joints shall be made at right angles to the 
 direction of the beam, girder, column or slab. 
 When work is resumed the joints shall be 
 thoroughly cleaned, drenched and slushed with 
 neat cement mortar. 
 
 Beams and girders shall not be constructed 
 over freshly placed columns without permit- 
 ting a period of at least ten (10) hours to 
 
 18 
 
elapse to provide for the shrinkage in the 
 columns. 
 
 The longitudinal steel in beams and girders 
 shall be so designed that there is a thickness 
 of concrete between the separate pieces of steel 
 of not less than one and one-half (1*4) times 
 the maximum sectional dimensions of the steel 
 and in no case less than one (1) inch. Some 
 means satisfactory to the Inspector of Build- 
 ings shall be used to hold all reinforcing steel 
 in its proper position. 
 
 Sec. 27. Centering and Forms. All forms 
 shall be substantially built and secured to pre- 
 vent movement or deflection during the prog- 
 ress of the work. They shall be tight to pre- 
 vent leakage of the concrete. An opening shall 
 be left at the bottom of all column forms for 
 removing foreign matter and adjusting the 
 steel, and said openings shall not be closed 
 until just before the concrete is poured. Be- 
 fore placing the concrete, the forms must be 
 thoroughly cleaned of all chips, .dirt, old con- 
 crete and other foreign matter. Forms shall 
 not be removed until the concrete has set suf- 
 ficiently to safely resist all stresses to which 
 it may be subjected. Two weeks of good dry- 
 ing weather with a temperature above 60 
 degrees Fahrenheit shall be taken as the min- 
 imum time for the removal of forms where 
 the concrete will support only its own weight. 
 The joists and lagging may be removed in 
 not less than ten days, providing the sheating 
 under the slabs is properly shored. The time 
 of removal of forms and^shores under heavy 
 beams and girders, varies with the design and 
 weather, but in no case shall they be removed 
 in less than three (3) weeks after pouring, pro- 
 viding the beams carry their own weight only. 
 When beams and girders carry construction 
 
 19 
 
loads from above, sufficient shores shall be left 
 in place to carry the loads until the completion 
 of the work. If sufficient shores are provided 
 to support the loads on slabs and girders, the 
 column forms may be removed in not less than 
 four (4) days. M 
 
 Sec. 28. Placing Concrete in Cold Weather. 
 
 When concrete is placed in freezing weather, 
 the material must be heated and such provi- 
 sions made that the concrete can be put in 
 place without freezing.. 
 
 The use of frozen lumpy sand or aggregate 
 depending on hot wateir used in mixing to thaw 
 it out, will not be permitted. All reinforced 
 concrete shall be kept at a temperature above 
 freezing for at least forty-eight (48) hours 
 after being put in place. All forms under con- 
 crete placed in freezing weather shall remain 
 until all evidences of frost are removed from 
 the concrete and the natural hardening of the 
 concrete has proceeded to the point of safety. 
 
 Sec. 29. Inspection. When any reinforced 
 concrete is used in construction, the owner 
 shall provide for the inspection of cement and 
 inerts ^ as required by this ordinance. Unless 
 otherwise authorized in writing by the* In- 
 spector of Buildings, the owner shall also pro- 
 vide a special inspector, who shall be on the 
 work continually during the building and 
 removing of forms and the placing of concrete 
 and steel. Said special inspector shall be 
 acceptable to the Inspector of Buildings, and 
 may be required to pass an examination given 
 by said Inspector. He shall make daily reports 
 to the Inspector of Buildings of the progress 
 of the work, on blanks furnished by the 
 department. 
 
 Sec. 30. Test for Safety. Within a reason- 
 
 20 
 
able time after erection, and before the build- 
 ing is occupied, a -test shall be made of the 
 work as directed by the Inspector of Buildings. 
 For such test the floor panels selected by said 
 Inspector must be loaded to twice the com- 
 puted live load and must sustain this load for 
 twenty-four (24) hours without undue deflec- 
 tion or other evident signs of failure. 
 
 Sec. 31. When to Take Effect. This ordi- 
 nance shall take effect and be in force from 
 and after the earliest period allowed by law. 
 
 DAVID T. LOGAN, 
 
 President of Council. 
 
 Passed April 7, 1913. 
 
 Approved April 7, 1913. 
 
 GEORGE J. KARB, Mayor. 
 
 Attest : 
 
 JOHN T. BARR, Clerk. 
 
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