diff --git "a/Concrete/practical_reinforced_concrete_buildings_1908.md" "b/Concrete/practical_reinforced_concrete_buildings_1908.md" new file mode 100644--- /dev/null +++ "b/Concrete/practical_reinforced_concrete_buildings_1908.md" @@ -0,0 +1,3853 @@ +PRACTICAL +REINFORCED CONCRETE +STANDARDS + +FOR THE DESIGN OF REINFORCED +CONCRETE BUILDINGS + +BY +H. B. ANDREWS, M. A.M. SOC. C. E. + +FIRST EDITION +FIRST THOUSAND + +PUBLISHED BY +SIMPSON BROS. CORPORATION +BOSTON + +COPYRIGHT 1938 BY H. B. ANDREWS + + + + + + + + + + + + + + + + + + +
123504
OCT 22 1908
SDKC
·AN2
+ +# PREFACE + +Among the many publications relating to reinforced concrete, there seem to be few that answer the requirements of the architectural designer. + +The majority of architects are men who studied for their profession before any thorough investigation of reinforced concrete construction had been made. They are now called upon by their clients to design in a material requiring special and intimate study of its characteristics, and the solution of intricate formulae to determine the proper composition, arrangement, and dimensions of its component parts. + +Many theories have been advanced by many authorities during the progress of scientific research and experiment. Revisions in these theories have been made from time to time until they now tend to converge toward a common focus, but as yet these theories have not been put in practical working shape, and as a result many structures for which reinforced concrete is specially adapted are built of other material. + +It is therefore the purpose of the author to publish information of reinforced concrete in the shape of standard sections, tables, and specifications, that will enable designs to be made in this material as rapidly and as intelligently as in wood or steel. + +The tables contained herein have been in practical use in designing and constructing several large buildings in the City of Boston and elsewhere, and the work designed has been approved by conservative concrete specialists. + +The need of a standard form of construction with standard specifications is often brought forcibly to mind by the failure of reinforced concrete structures through no fault of the materials entering therein, but through the lack of knowledge by the architect, inspector, or contractor of the design or handling of the materials which enter into the work. + +This work is divided into five chapters: + +1. A Brief Theory of Reinforced Concrete Construction, including original formulae by the author for moments of resistance of T-beams and tables of standard sections. +2. Miscellaneous Tables. +3. A Reinforced Concrete Code. +4. Standard Specifications. +5. Foundations. + +It is the author's purpose to make this book as valuable as possible for practical designing and building, and to that end will invite suggestions from all interested so that use can be made of them, if found practical, for future editions. + +H. B. ANDREWS. + +Boston, January, 1908. + +I + +CONTENTS + +CHAPTER I +STANDARD SECTIONS + +Design of Reinforced Concrete Beams .................................................. 1 +Illustrations of Use of Diagrams and Tables ........................................... 4 +Standard Sections - Typical Section of Floor ......................................... 6 +Bending Moments - Formulae ............................................................. 7 +Diagram for Designing Reinforced Concrete Slabs .................................... 9 +Diagram of Bending Moments .............................................................. 10 +Elements of Reinforced Concrete Beams .................................................. 11 +Working Loads for Reinforced Concrete Columns ....................................... 17 + +CHAPTER II +TABLES + +Weights and Areas of Square and Round Steel Rods. Welded and Expanded Metal .................................................................................................................. 18 +Proportions of Concrete Aggregates .......................................................... 19 +Crushing Strength of Portland Cement Concrete .......................................... 20 +Material for 100 Sq. Ft. Concrete Sidewalk or Floor .................................... 21 +Safe Loads for Wooden Beams ..................................................................... 22 + +CHAPTER III +A REINFORCED CONCRETE CODE .................................................................. 23 + +CHAPTER IV +REINFORCED CONCRETE SPECIFICATIONS .................................................. 28 + +CHAPTER V +FOUNDATIONS + +Loading ........................................................................................................... 41 +Classes of Foundations .............................................................................. 42 +Foundations directly upon the Soil ............................................................ 42 +Pile Foundations ....................................................................................... 45 + +. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . + +PRACTICAL REINFORCED CONCRETE +STANDARDS + +CHAPTER I +STANDARD SECTIONS + +DESIGN OF REINFORCED CONCRETE BEAMS + +A diagram showing the dimensions of a reinforced concrete beam. The diagram includes labels for various parts such as the web (b), flange (b'), effective depth of beam (d), distance from top to neutral axis (d/2), full depth of beam (h), depth of flange (h'), distance from lower side of flange to neutral axis (m/d'h'), distance between centroid of compression and neutral axis (n), distance between centroid of compression and centroid of tension (c), unit compression in concrete at top of flange (c'), unit compression in concrete at bottom of flange (e'), unit stress in steel (s), total compression in concrete (S), and total stress in steel (C). The diagram also shows the centroids of compression and tension. + +NOTATION + +\begin{align*} +b & - \text{breadth of web.} \\ +b' & - b + 4h' - \text{breadth of flange.} \\ +d & - \text{effective depth of beam.} \\ +\frac{d}{2} & - \text{distance from top of beam to neutral axis.} \\ +h & - \text{full depth of beam.} \\ +h' & - \text{depth of flange.} \\ +m & - \frac{d}{q} h' - \text{distance from lower side of flange to neutral axis.} \\ +n & - \text{distance between centroid of compression and neutral axis.} \\ +a & - \text{distance between centroid of compression and centroid of tension} - \text{Moment arm.} \\ +c & - \text{unit compression in concrete at top of flange.} \\ +c' & - \text{unit compression in concrete at bottom of flange.} \\ +s & - \text{unit stress in steel.} \\ +C & - \text{Total compression in concrete} = S, \text{total stress in steel.} +\end{align*} + +Pn. 1 + +2 +PRACTICAL REINFORCED CONCRETE STANDARDS + +FORMULAE + +The following assumptions are made in obtaining formulae: + +I. A uniform horizontal compression in flange for a distance of twice the depth of flange each side of web. Making this the maximum width of flange tends to avoid the danger of shear along the web. + +II. That the compression in the concrete varies uniformly from the neutral axis to the top of the flange. + +III. That under working loads, and until the steel is stressed beyond its elastic limit, the neutral axis will lie approximately midway between the top of the beam and the centre of tension. This assumption has been corroborated by tests made to destruction of several T-beams, reinforced with different percentages of steel, at the Massachusetts Institute of Technology, the location of the neutral axis being carefully determined at each increment of load. + +IV. That the total compression in the concrete will be balanced by an equal tension in the steel. + +V. No allowance is made for tensile strength of concrete. + +In Fig. 1 consider first a rectangular section of width $b'$ and of depth $d$, then the theoretical compression due to any load + +$$\frac{b'd}{2} \times \frac{c'd'}{2} = \frac{cb'd'}{4}$$ (1) + +This can be represented by a triangle as shown by Fig. No. 2, where it is shown that the centre of compression will be at the centre of gravity of the triangle or two thirds of the distance $\frac{d}{3}$ above the neutral axis. + +The resistance moment about the neutral axis + +$$\frac{cb'd}{4} \times \frac{d}{3} = \frac{cb'd'}{12}$$ (2) + +Considering next the two areas bounded by $m$ and $2h'$, the theoretical compression + +$$\frac{4ch'm}{2} = 2ch'm,$$ (3) + +and its moment about the neutral axis + +$$-2ch'm \cdot \frac{2m}{8} = -\frac{4ch'm^2}{5},$$ (4) + +The actual compression in the T-section equals the difference between formulae (1) and (3) + +$$-\frac{cb'd}{4} - 2ch'm = C - S.$$ (5) + +STANDARD SECTIONS s + +and the resultant resistance moment about the neutral axis equals the difference between formulae (8) and (4) + +$$\frac{c'b^3}{4} - \frac{4c'h'm^3}{3}.$$ (6) + +The quotient of the resultant resistance moment divided by the total compression is the resultant moment arm, or + +$$n = \frac{\frac{12}{3}}{\frac{c'b^3}{4} - 2c'h'm} = \frac{c'b^3 - 16c'h'm^3}{3(c'b^3 - 24c'h'm)},$$ (7) + +$$c' = \frac{2cm}{d};$$ eliminating $c'$ by substitution in equation (7) and dividing both members by $c$ it becomes + +$$n = \frac{b'd^3 - 92h'm^3}{8b'd^3 - 48h'm^3}. $$ (8) + +To determine the moment of resistance of a beam when the tension in the steel is known, take moments around the centre of compression in the concrete with a moment arm + +$$a = \frac{d}{2} + n,$$ then $Mr = aS.$ (9) + +$S$ must never exceed the value of $C$ obtained by assuming the maximum unit stress $c$; it may, however, be less than this value, and the moment of resistance obtained by using the maximum value of $c$ will be decreased in proportion to the decreased value of $S$. + +**SHEAR** + +The diagonal tension existing in the web of a concrete beam may be resolved into vertical and horizontal components, each of which equals the vertical shear due to load at the section considered. The horizontal component will be taken care of by the horizontal beam rods. The vertical component will be taken care of by the concrete, provided it is not stressed over 60 lbs. per sq. inch of effective cross-section, i.e. the area included in the web between the centroid of compression in the concrete and the centroid of tension in the steel, or distance "a" in the tables. If stressed beyond this, the full vertical component must be taken care of by stirrups of steel, in a horizontal distance equal to "a". + +The stirrups should not be farther apart than $\frac{1}{2}$ "a," as with any wider spacing they would lose part of their value. + +Let $V$ = total external vertical shear at cross section considered, + +$$v = \text{shear per sq. in. cross-section},$$ + +$$a = \text{effective depth between centroid of compression in concrete and centroid of tension in steel};$$ then + +$$v = \frac{V}{ab}. $$ (10) + +1 This assumption is made on the basis of using a 1-8-4 mixture of concrete. + +PRACTICAL REINFORCED CONCRETE STANDARDS + +If $v$ exceeds 50, provide stirrups spaced so that their tensile strength in a length of beam not exceeding $a$ is equal to $V$. + +If beam rods are trussed, the value of the vertical component of the trussed rods may be utilized. + +This value we will call $W$. + +$$W = A \times s \times \frac{a}{3.1}$$ (11) + +Where $A$ - sectional area of steel in trussed rods, +$s$ - working stress of steel, +$a$ - effective depth, +$3.1$ - horizontal length trussed portion; all dimensions being used as inches. + +If $T$ represents tensile strength of stirrups in length of beam = "a," then + +$$T = V - W.$$ (18) + +To locate the section where the vertical shear is just 60 lbs per sq. inch, let $x$ - distance of this section from point of support, $l$ - span in feet, $d$ and $b$ as already used in previous formula, and $W$ the load per linear foot of beam or girdor; then + +$$x = \frac{l}{2} \cdot \frac{30db}{W}$$ (19) + +ILLUSTRATIONS OF USE OF DIAGRAMS AND TABLES + +The diagram shown on page 9 is for use in obtaining graphically the thickness and reinforcement of floor slabs. For illustration, assume a superimposed load of 125 lbs. per sq. ft. and a dead load which includes the weight of the slab, approximated, of 75 lbs. per sq. ft., making a total load of 200 lbs. per sq. ft. to be carried on a span of, say 12 feet. + +The horizontal lines measure the span in feet and the curved diagonal lines the bending moment in foot pounds. Follow the vertical line from the figure 12 to the point where it intersects the diagonal line marked 200 lbs. per sq. ft., and thence horizontally left to the columns marked "Thickness of slab in inches." The thickness of slab may be selected from one of these columns, and the amount of reinforcement to be used with it is shown by the figures in the column, remembering, as a general rule, that the minimum thickness of slab and the maximum amount of reinforcement is the most economical. For the example given the thickness of slab would be 6" and the reinforcement about .58 sq. inch in sectional area for one foot in width of slab. Interpolation can be made in both the diagram and figures for any of the factors entering into the problem. + +The diagram shown on page 10 is used similarly for obtaining the bending moments due to combined live and dead loads for beams. After the bending moment due to the load is obtained, a section of beam whose moment of resistance is equal to this bending moment may be selected from the tables marked "Elements of reinforced concrete beams." + +For illustration, if the combined live and dead loads on a beam with a span of + +STANDARD SECTIONS 5 + +20 feet is 3000 lbs. per lin. ft. of beam, then the bending moment of 150,000 foot lbs. is obtained at the left hand side of the diagram. Referring to the tables, it is found that beams $E-10-26$, $F-10-26$, $G-10-26$, $D-10-80$, $E-12-44$, $F-18-44$, $G-18-24$, and $E-18-26$ with moments of resistance varying from 140,730 to 157,000 foot lbs. will practically fill the requirements. Take, for example, the beam $E-18-26$. The letters from $C$ to $G$ represent thickness of the slab on flange of the T-beam of from 8" to 7". The letter $E$, therefore, represents a thickness of 8". The first figure, 12, is the thickness of the stem, and the last figure, 26, the total depth of beam including slab. The first column in the table shows the maximum unit compressive stress in the concrete; the second column, the total compressive stress in concrete or tensile stress in steel; the third, the moment arm or distance between centroids of compression and tension; the fourth, the moment of resistance of beam in foot pounds; the fifth and sixth, the size of straight and trussed round rods used for reinforcement; the seventh, the sectional area of reinforcement; the eighth, the weight of reinforcement per lin. ft., and the ninth, the sectional area of concrete under the slab. + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
$E$$F$$G$$D$$E$$F$$G$$D$$E$
121212121212121212
8"8"8"8"8"8"8"8"8"
9"9"9"9"9"9"9"9"9"
10"10"10"10"10"10"10"10"10"
Total Depth of Beam Including Slab (in.)
Maximum Unit Compressive Stress in Concrete (psi)
Total Compressive Stress in Concrete or Tensile Stress in Steel (psi)
Moment Arm or Distance Between Centroids of Compression and Tension (in.)
Moment of Resistance of Beam in Foot Pounds
Size of Straight and Trussed Round Rods Used for Reinforcement (in.)
Sectional Area of Reinforcement (sq. in.)
Weight of Reinforcement Per Lin. Ft.
Sectional Area of Concrete Under Slab (sq. ft.)
+ +A page from a technical manual or textbook discussing standard sections for beams and slabs. + +The first figure, 12, is the thickness of the stem, and the last figure, 26, the total depth of beam including slab. The first column in the table shows the maximum unit compressive stress in the concrete; the second column, the total compressive stress in concrete or tensile stress in steel; the third, the moment arm or distance between centroids of compression and tension; the fourth, the moment of resistance of beam in foot pounds; the fifth and sixth, the size of straight and trussed round rods used for reinforcement; the seventh, the sectional area of reinforcement; the eighth, the weight of reinforcement per lin. ft., and the ninth, the sectional area of concrete under the slab. + +6 PRACTICAL REINFORCED CONCRETE STANDARDS + +STANDARD SECTIONS. + +TYPICAL SECTION OF FLOOR. + +A diagram showing various standard sections of reinforced concrete structures. + +1 + +STANDARD SECTIONS +BENDING MOMENTS + +FORMULAE FOR BENDING MOMENTS + +(1) +Beam fixed at one end, with concentrated load. +$$B.M. = WL$$ + +(2) +Beam fixed at one end, with uniformly distributed load. +$$B.M. = \frac{WL}{2}$$ + +(3) +Beam fixed at one end, with combination of uniformly distributed and concentrated loads. +$$B.M. = PL + \frac{WL}{2}$$ + +(4.) +Beam supported at both ends, with concentrated load in middle. +$$B.M. = \frac{WL}{4}$$ + +(5.) +Beam supported at both ends, with uniformly distributed load. +$$B.M. = \frac{WL}{8}$$ + +(6.) +Beam supported at both ends, with concentrated load not at centre. +$$B.M. = \frac{WMN}{L}$$ + +8 +PRACTICAL REINFORCED CONCRETE STANDARDS + +(7) +Beam supported at both ends, with equal and symmetrical concentrated loads. +B. M. = WM. + +GRAPHICAL METHOD OF DETERMINING BENDING MOMENTS. + +(1) Beam supported at both ends, with one concentrated load, to find the bending moment at any part of the beam. + +Let $W$ be the weight as shown; then, as previously given, the bending moment at $W = \frac{WMN}{L}$. Plot the beam and the location of $W$ to some convenient scale, then to this, or some other scale, measure the line $WB$ equal to the bending moment already found. Connect $B$ with each end of the beam. Then if we wish to find the bending moment at some point, as $E$, draw $DE$ vertically to line $CB$. Measure $DE$ with same scale used in measuring $WB$. The result will be the bending moment at $E$. + +(8) Beam with two concentrated loads. + +Let $W$ and $P$ be the two concentrated loads as shown. Plot the bending moments $WB$ and $PC$ due to each of these loads by formula already given. Complete the diagram for each load by drawing $ABD$ and $ACD$. Now the total bending moment at $W$ would be $WE$, due to load $W$, plus $WE$, due to load $P$, or $WB$; and the total bending moment at $P$ would be $PC$, due to load $P$, plus $PF$, due to load $W$, or $PC$. + +Draw the outline $ABCD$, and this will represent the bending moment due to both loads, and will be the greatest where the vertical height scales the most. + +This method can be employed to find the bending moment due to any number of concentrated loads. + +(8) Beam with uniformly distributed load. + +At the middle of the beam draw the line $AB = \frac{WL}{8}$. + +Connect the points $C B D$ by a parabola and it will give the outline of the bending moments. + +(4) Beam loaded with both distributed and concentrated loads, + +Plot the outline of the bending moments due to the concentrated loads as per Case No. 2, and for the distributed load as per Case No. 3. The vertical distance between the upper and the lower outline at any point will be the bending moment at that point. + +STANDARD SECTIONS + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Diagram for Designing Reinforced Concrete Slabs
Thickness of Slab in inchesB.M.W.L.
3/4 5/6 7/8 9/1010 Piles9,000
8 Piles8,500
6 Piles8,000
5 Piles7,500
4 Piles7,000
3 Piles6,500
2 Piles6,000
1 Pile5,500
1/2 Pile5,000
1/4 Pile4,500
1/8 Pile4,000
1/16 Pile3,500
1/32 Pile3,000
1/64 Pile2,500
1/128 Pile2,000
1/256 Pile1,500
Reinforcement, Sectional Area Per Ft. Width:
Span in Feet:
+ +A graph showing the relationship between span length (in feet) and reinforcement requirements for reinforced concrete slabs. The x-axis represents span lengths from 3 to 12 feet. The y-axis represents reinforcement requirements in pounds per linear foot. The graph shows different curves for different thicknesses of slab (3/4", 5/6", etc.) and pile counts (8 piles, 6 piles, etc.). The curves are labeled with reinforcement values in pounds per linear foot. + +9 + +10 +PRACTICAL REINFORCED CONCRETE STANDARDS +DIAGRAM OF BENDING MOMENTS +B. M. = W L² + 8 + +A graph showing bending moment in foot pounds versus span in feet. The x-axis ranges from 10 to 30 feet, and the y-axis ranges from 50,000 to 600,000 foot pounds. The lines on the graph represent different values of bending moment. + +BENDING MOMENT IN FOOT POUNDS + +SPAN IN FEET + +50,000 +100,000 +150,000 +200,000 +250,000 +300,000 +350,000 +400,000 +450,000 +500,000 +550,000 +600,000 + +STANDARD SECTIONS +11 + +ELEMENTS OF REINFORCED CONCRETE BEAMS + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
No. of Beamss0=8aMr In ft. lbs.Size of RodsSec. Area of Steel per ft. ft. lbs.Wt. of Steel per ft. ft. lbs.Cu. ft. of Concrete under slab
BentStraight
4-8663397651657One 9-10" 2485 .8451.043 .222
C-4-8401962154009" 7-8" 6013 2.044 .138
D-4-8321962154009" 7-8" 6013 2.044 .111
E-4-8267962154009" 7-8" 6013 2.044 .083
+ + + + + + + + +
No. of Beams s0=8aMr In ft. lbs.Size of RodsSec. Area of Steel per ft. ft. lbs.Wt. of Steel per ft. ft. lbs.Cu. ft. of Concrete under slab
Elements of Reinforced Concrete Beams:
No. of Beams s
C-4-8
D-4-8
E-4-8
F-4-8
G-4-8
H-4-8
I-4-8
J-4-8
K-4-8
L-4-8
M-4-8
N-4-8
O-4-8
P-4-8
Q-4-8
R-4-8
S-4-8
T-4-8
U-4-8
V-4-8
W-4-8
X-4-8
Y-4-8
Z-4-8
A-5-8
B-5-8
C-5-8
D-5-8
E-5-8
F-5-8
G-5-8
H-5-8
I-5-8
J-5-8
K-5-8
L-
+ + +
No. of Beams sC=5, D=5, E=5, F=5, G=5, H=5, I=5, J=5, K=5, L=5, M=5, N=5, O=5, P=5, Q=5, R=5, S=5, T=5, U=5, V=5, W=5, X=5, Y=5, Z=5, A=6, B=6, C=6, D=6, E=6, F=6, G=6, H=6, I=6, J=6, K=6, L=6, M=6, N=6, O=6, P=6, Q=6, R=6, S=6, T=6, U=6, V=6, W=6, X=6, Y=6, Z=6,
+ + +
No. of Beams sC=7, D=7, E=7, F=7, G=7, H=7, I=7, J=7, K=7,
+ + +
No. of Beams s
No. of Beams s
No. of Beams s

+ +12 PRACTICAL REINFORCED CONCRETE STANDARDS + +ELEMENTS OF REINFORCED CONCRETE BEAMS + +
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +STANDARD SECTIONS +18 + +**ELEMENTS OF REINFORCED CONCRETE BEAMS** + +
No. of BeameC = gaMr In ft. lbs.Size of RodsSec. Area of Steel per ft. lbs.Wt. of Concrete under Slab
BentStraightSteelConcrete
S-8-145891413810.0011782One
“
“
“		3-4"One
Two
“
“		8836
1.9880
2.1721
2.1721
2.1721
2.1721		3.005
6.759
7.385
7.385
7.385
7.385		.777
.611
.555
.445
.390
C-8-14652318089.6625605“
“


3-4"One
Two


D-8-14547347539.4827455-7-8"
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E-8-14447347539.3627107-7-8"
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"		"
"
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"
F-8-14388347539.3327020-7-8"
"
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"
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No. of BeameC = BaMr in ft. lbs.Size of RodsSec. Area of Steel per ft. lbs.Wt. of Steel per ft. lbs.Sec. Area Concrete under Slab
10-166762375911.6723106One 7-8" Two 3-4"1.48495.0491.111
C-10-166203769811.3935782" 1" " 1"2.35628.011.903
D-10-166615026410.0248740Two 1" " 1"3.141610.681.833
E-10-165415026410.7848154" 1" " 1"3.141610.681.763
F-10-164635026410.6744693" 1" " 1"3.141610.681.693
G-10-164135026410.6244484" 1" " 1"3.141610.681.623
+ + + + + + + +
No.e (in)C = B (in)a (in)Mr (ft-lbs)Rods Size (in)Rods No.Rods Wt.Rods Area (in²)
Elements of Reinforced Concrete Beams:
No.e (in)C = B (in)a (in)Mr (ft-lbs)Rods Size (in)Rods No.Rods Wt.Rods Area (in²)
+ + + +
No.e (in)C = B (in)a (in)Mr (ft-lbs)Rods Size (in)Rods No.Rods Wt.Rods Area (in²)
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+ +
A table showing elements of reinforced concrete beams with various beam sizes, rod diameters, and weights./page_number + +14 PRACTICAL REINFORCED CONCRETE STANDARDS + +**ELEMENTS OF REINFORCED CONCRETE BEAMS** + +
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
No. of BeameCm-SaAir in ft. lbs.Size of RodsBentSec. Area of SteelWt. of Steel per ft. ft.Sec. Area Concrete under Slab
Straight
10-286834437421.6780152One 1°Two 1-1/8°2.77349.4301.944
C-10-286676283021.74113027Two 1°Three 1°3.027813.3521.736
D-10-286847362021.88144991One 1-1/8°Three 1-1/8°4.970016.5981.667
E-10-286959542421.97152717Three 1-1/8°One 1-1/8°6.064020.2781.598
F-10-285589542421.60171755One 1-1/8°" " 1-1/8°"" " 1-1/8°"
G-10-28471
odd row color:even row color:even row color:$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]$data[]15 + +**ELEMENTS OF REINFORCED CONCRETE BEAMS** + +
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
No. of BeameC=8aM-to-ft. lb.Size of RodsBentStraightSec. Area of Steel per lin. ft.Sec. Area Concrete under Slab
12-286444810020.7583173Two 7-8" Three 7-8"3.006510.2222.333
C-12-286857284421.55130618" 1" " 1 1-8"4.553815.4802.053
D-12-287069068621.67163764" 1 1-8" " 1 1-4"5.667519.2702.000
E-12-2869110659021.63919218Three 1 1-8" " 1 1-4"6.661822.5501.917
F-12-2864111776621.52211716" 1 1-4" " 1 1-4"7.359625.0231.833
G-12-2854811776621.38299982" 1 1-4" " 1 1-4"7.3596
under Slab
under Slab
under Slab
under Slab
under Slab
under Slab
<
under Slab
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +16 +PRACTICAL REINFORCED CONCRETE STANDARDS + +ELEMENTS OF REINFORCED CONCRETE BEAMS + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
No. of BeameC = BaM or ft. lb.Size of RodsSec. Area of Steel per ft. lb.Sec. Area Concrete under Slab
BentStraight
15-276786361620.83110427Two 1 1-8"Two 1 1-8"3.9960
13.586
C 15-276718207220.84143368" 1 1-8"Four 1"5.1296
17.441
D 15-276629542420.96166074Three 1 1-8"Three 1 1-8"5.9460
20.278
E 15-2765811332820.91190405" 1 1-8"Four 1 1-8"6.0588
23.657
F 15-2763912021620.92196881" 1 1-8"" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 1 1-4"
" 3.9960
5.9460
6.0588
7.8884
7.8884
7.8884
7.8884
7.8884
7.8884
7.8884
7.8884
7.8884
7.8884
7.8884
7.8884
7.8884
7.8884
7.8884
7.8884
7.8884
7.8884
7.8884
7.8884
7.8884
7.8884
7.8884
7.8884
7.9232
+ + + +
+ + + + +
No.eC = BaM or ft.Size of RodsSec.Wt.of SteelSec.Area Concrete +
A square with a diagonal line through it. +A circle with a diagonal line through it. +A hexagon with a diagonal line through it. + +\begin{tabular}{l l l l l l l} +\multicolumn{7}{c}{\textbf{Working Loads for Reinforced Concrete Columns}} \\ +\multicolumn{7}{c}{\textbf{Square per Sq. In.}}} \\ +\multicolumn{7}{c}{\textbf{Round per Sq. In.}}} \\ +\multicolumn{7}{c}{\textbf{Octagonal per Sq. In.}}} \\ +\multicolumn{7}{c}{\textbf{Square per Sq. In.}}} \\ +\multicolumn{7}{c}{\textbf{Round per Sq. In.}}} \\ +\multicolumn{7}{c}{\textbf{Octagonal per Sq. In.}} +\end{tabular} + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Dim. "A"SquareRoundOctagonalSquareRoundOctagonal
12 ins.Lbs. 72,xxxLbs. xxxLbs. xxxLbs. xxxLbs. xxxLbs. xxx
138,xxxxxxxxxxxxxxxxxx
149,xxxxxxxxxxxxxxxxxx
151,xxxxxxxxxxxxxxxxxx
16xx,xxxxxxxxxxxxxxxxxx
17x,xxxx,xxxx,xxxx,xxxx,xxxx,xxx
18x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,xxref_id:
+ +A square with a diagonal line through it. + +A circle with a diagonal line through it. + +A hexagon with a diagonal line through it. + +- \textbf{-} \textbf{28} - \textbf{-} \textbf{39,xxx} - \textbf{-} \textbf{42,xxx} - \textbf{-} \textbf{43,xxx} - \textbf{-} \textbf{44,xxx} - \textbf{-} \textbf{45,xxx} - \textbf{-} \textbf{46,xxx} - \textbf{-} \textbf{47,xxx} - \textbf{-} \textbf{48,xxx} - \textbf{-} \textbf{49,xxx} - \textbf{-} \textbf{50,xxx} - \textbf{-} \textbf{51,xxx} - \textbf{-} \textbf{52,xxx} - \textbf{-} \textbf{53,xxx} - \textbf{-} \textbf{54,xxx} - \textbf{-} \textbf{55,xxx} - \textbf{-} \textbf{56,xxx} - \textbf{-} \textbf{57,xxx} - \textbf{-} \textbf{58,xxx} - \textbf{-} \textbf{59,xxx} - \textbf{-} \textbf{60,xxx} - \textbf{-} \textbf{61,xxx} - \textbf{-} \textbf{62,xxx} - \textbf{-} \textbf{63,xxx} - \textbf{-} \textbf{64,xxx} - \textbf{-} \textbf{65,xxx} - \textbf{-} \textbf{66,xxx} - \textbf{-} \textbf{67,xxx} - \textbf{-} \textbf{68,xxx} - \textbf{-} \textbf{69,xxx} - \textbf{-} \textbf{70,xxx} + +A square with a diagonal line through it. + +A circle with a diagonal line through it. + +A hexagon with a diagonal line through it. + +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Page _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
+ +CHAPTER II + +WEIGHTS AND AREAS OF SQUARE AND ROUND STEEL RODS, WELDED AND EXPANDED METAL + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Weights and Areas of Round and Square Steel RodsWelded Metal
Dia. in
16ths		Area G
Sq. In.		Weight G
Lbs.		Area C
Sq. In.		Weight C
Lbs.		Size Longitudinal
Wire W. and M.
Long. Lbs.		Area For Post in Width
Sq. In.		Size Central
Sq. In.		Size Central
Sq. In.		Size Central
Sq. In.
0-1.0039.013.0031.010No. 0.07384427.2951.2213
2.0156.053.0128.0421.06133680.2453.1940
3.0352.119.0276.0942.05413347.2165.1624
4.0625.312.0491.1673.04662798.1866.1399
5.0958.523.0761.3214.03992392.1595.1196
61.406478.104


































































































+ +
Expanded Metal
Description
No. of Rows
No. of Bars
No. of Bars per Row
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No. of Bars per Row
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No. of Bars per Row
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No. of Bars per Row
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No. of Bars per Row
No. of Bars per Row
No. of Bars per Row
No. of Bars per Row
No. of Bars per Row
No. of Bars per Row) + +
Expanded Metal Description No.of Rows No.ofBars No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRow No.ofBarsperRowNoofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsofRowsNoofBarsof.Rows + +
Expanded Metal Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description Description DescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptionDescriptio... + +TABLES 19 + +PROPORTIONS OF CONCRETE AGGREGATES + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Proportions of Mixtures
Materials Required for 1 Cubic Yard
Proportions of Mixtures
With Handled Stone
CementSandStoneBarrilsOn Yda BandOn Yda CementBarrilsOn Yda BandCe Yda StoneCe Yda CementCe Yda SandCe Yda Stone
1122.570.390.782.630.400.802.330.350.75
112.52.290.350.872.340.360.892.100.320.80
1132.060.310.942.100.320.961.890.290.86
Required for 1 sub. yd. dry mortar with No 3 Hand:
Cement Billo.
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+ + + + + + + +CHAPTER III + +CODE USED FOR THE DESIGN OF STANDARD REINFORCED CONCRETE SECTIONS + +1. The bond between concrete and steel is sufficient to make the two materials act as a homogeneous solid aggregate. +2. The design shall be based on the assumption of the total live and dead load producing a stress of 16,000 pounds per square inch in the reinforcement, and a corresponding stress in the concrete of not over 700 pounds per square inch at the extreme fibre. +3. The stress in any fibre is directly proportional to the distance of that fibre from the neutral axis. +4. The modulus of elasticity of concrete remains constant within the limits of the working stresses. +5. The dimensions of all weight-bearing members submitted to transverse stresses shall be so proportioned that the strength of the metal in tension shall determine the strength of the member. +6. The tensile strength of concrete shall not be considered. +7. No metal shall be added to the compression side of a member to assist it in compression. +8. In the design of structures involving reinforced concrete beams and girders in connection with slabs, the beams and girders shall be treated as T-sections, with a portion of the slab acting as a flange. This portion of the slab shall be assumed to have a width equal to four times its thickness plus the width of the beam. +9. For all working loads, the neutral axis of any slab, beam, or girder shall be assumed midway between the centroid of compression of the steel in tension and the top of the member. +10. The ultimate shearing strength of concrete shall be assumed as one tenth its compressive strength. +11. All reinforced concrete girders acting as T-sections must be reinforced against shearing stress along the plane of junction of the rib and the flange. +12. Concrete in direct compression shall be assumed to have the following working values: +
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
1-3-0mix, 400 lbs. per sq. in.
1-2-5“ 450 “ “ “ “
1-2-4“ 500 “ “ “ “
1-1-3“ 600 “ “ “ “
1-1-2“ 700 “ “ “ “
+ +Reinforced concrete columns shall be designed with the assumption that the stress in the concrete shall be simultaneous with ten times the stress per square inch in the steel. + +84 + +**PRACTICAL REINFORCED CONCRETE STANDARDS** + +13. In carrying out work in the field, special care must be taken that the ribs of all girders and beams shall be monolithic with the floor slab for a distance of twice the depth of slab each side of rib. + +14. Care must be taken to introduce steel enough to prevent cracks developing from tensile stresses due to the continuity of the members. + +15. In the determination of bending moments, beams and girders shall be considered as supported at the ends, no allowance being made for continuity over supports, and the bending moment shall be figured as $\frac{Wl}{8}$ + +16. Floor slabs when constructed continuous, and when provided with reinforcement at the top of slab over supports, may be treated as continuous beams, the bending moment being taken as $\frac{Wl}{10}$ for uniformly distributed loads, or in case of slabs supported on four sides and reinforced in each direction, as $\frac{Wl}{20}$. + +17. Where concrete is exposed to extreme changes of temperature it should be reinforced to the extent of 008 of 1 per cent. of sectional area of concrete for every degree of estimated variation of temperature, to prevent cracks developing. + +18. When the shearing stresses developed in any part of a reinforced concrete structure exceed the shearing strength of concrete, as fixed, a sufficient amount of steel shall be introduced in such a position as to take care of the full shearing stress. + +19. The full estimated strength of plain or reinforced concrete columns shall not be used where the length is more than 15 times the least side or diameter. + +**DISCUSSION OF REINFORCED CONCRETE CODE** + +Board. In order to develop the bond between concrete and steel, all trussed rods over columns, or rods where the stress is transmitted from one to another, shall have a lap of at least 40 diameters. + +In continuous columns where the stress in the steel is assumed to be 5000 or 6000 pounds per square inch, the lap may be 15 to 18 diameters. All trussed rods ending at wall beams, or elsewhere, where the bond is not developed by the length of the rod, must have an anchorage sufficient to develop their strength. The best method of obtaining this anchorage, where round rods are used, is to thread the end of the rod, and fit it with a wrought iron or steel plate washer with an area of at least 24 times the sectional area of the rod, with two nuts, one on each side of the plate to hold it firmly in place. Tension rods should be separated by a distance of at least one and one half times their diameter, and should be no nearer the face of the concrete. + +Steel must be free from paint or oil, and all rust scales must be removed before inbedding in concrete, as these will prevent the proper adhesion of the concrete to the steel. + +Stirrups used for shearing stress should be anchored both at the top and the bottom of the beam. + +A REINFORCED CONCRETE CODE 25 + +**STRESS IN STEEL AND CONCRETE.** The stress of 16,000 pounds per square inch in the steel is that usually assumed for the working stress in structural steel in building construction, and there is no good reason why the same working stress should not apply to concrete reinforcement. The assumed maximum compressive stress of 700 pounds per square inch in the concrete is that obtained by the straight line theory, and is actually considerably less, as the stress strain curve will follow more nearly the line of the parabola as shown in cut. + +If, however, the stress in the steel produced a maximum stress of 700 pounds per square inch in a concrete the ultimate strength of which is four times as much, then the first signs of failure in a properly designed beam would not result from compression, but from the elongation of the tension steel and the consequent cracks in the bottom of the beams resulting therefrom, which begin to show plainly when the steel is stressed to about 40,000 pounds per square inch. + +**MODULUS OF ELASTICITY.** The ratio of the moduli of elasticity of concrete and steel is neglected in the design of transverse weight-bearing members, as this ratio is always a variable depending upon the mixture of concrete and its age. It seems as reasonable to adopt a fixed position of the neutral axis as to adopt a fixed ratio for the moduli of elasticity upon which the position of the neutral axis would depend. + +Rules 3 and 4 are therefore correlative. + +**RELATIVE DIMENSIONS.** If a beam is so proportioned that the strength of the steel determines the strength of the beam, then ample warning will be given before failure by overloading; if, on the other hand, the strength of the beam is determined by the strength of the concrete in compression, the beam will fail without warning, with possible disastrous results. + +**TENSILE STRENGTH OF CONCRETE.** The tensile strength of concrete is neglected for the following reasons: + +The steel is undoubtedly assisted in tension by the concrete until the elastic limit of the concrete is reached, which will be when the steel is stressed to about 6000 pounds per square inch. At this point numerous microscopic cracks will occur at the bottom of the beam, which, while not visible and in no way affecting the integrity of the beam, completely eliminates the tensile strength of the concrete. These cracks will not become visible to the naked eye until after the elastic limit of the steel is reached. + +No Metal in Compression. The exact value of metal in compression in a beam is an undetermined quantity and is also not economical in design. It therefore should be eliminated from any standard sections, and in case it is necessary to use steel in compression to reduce the size of a member, special consideration should be given its design. + +A diagram showing a cross-section of a beam with a neutral axis labeled "NEUTRAL AXIS". The diagram illustrates how stress distribution occurs within a beam. + +26 + +**PRACTICAL REINFORCED CONCRETE STANDARDS** + +**WIDTH OF FLANGE OF T-SECTIONS.** Various assumptions of the width of flange have been made by engineers. Some base the width of flange upon the span of beam, others upon the thickness of slab. While this width undoubtedly depends more or less upon both elements, the author thinks it wise to base it upon the depth of slab for standard sections, as it limits the danger of failure from longitudinal shear along the junction of web and flange, and no standard sections would be possible if the span had to be taken into consideration each time. + +**LOCATION OF NEUTRAL AXIS.** The location of neutral axis is assumed midway between the top of the slab and the centroid of tension in the steel. Tests made to destruction, on full-sized beams reinforced with different percentages of steel in which the position of the neutral axis at each successive increment of load was carefully determined, show that there is no great variation from this location until after the elastic limit of the steel is passed. The author is of the opinion that the position of the neutral axis is more dependent on the unit stress in the concrete than on the unit stress in the steel. + +**STRENGTH OF CONCRETE IN DIAGONAL TENSION.** The tensile strength of concrete is usually assumed to be equal to about one tenth its compressive strength. The working value of a 1–2–4 concrete in diagonal tension, usually called shear, may be assumed to be 80 pounds per square inch. + +Referring to rule 11, floor beams are always reinforced sufficiently against shear along the junction of rib and flange by the floor slab reinforcement. This reinforcement, however, does not occur across girders, and it is good conservative practice to reinforce the top of the slab across girders to provide against this shearing action and also to transmit a part of the load on the floor slab directly to the girders by means of the cantilever action thus developed. The slab reinforcement parallel to the girder may be omitted for a little way each side of girder. + +**STRESSES IN COLUMNS.** The less steel in columns, other than that needed for flexure, tends to economy. After forms are in place we will assume that a 1–14–8 concrete with a working value of 600 pounds per square inch may be deposited for eight dollars per yard or approximately thirty cents per cubic foot. This gives a supporting value of $144 \times 800 = 86,400$ pounds one foot in height for thirty cents. A sectional area of 14.4 square inches of steel weighing 49 pounds and costing in place about one dollar and a half per lineal foot would be necessary to carry the same load. + +However, in high buildings with heavy loads it is often necessary to limit the size of concrete columns by the introduction of steel. Steel reinforcement may be used with economy up to 5 per cent. of the sectional area of the column, but if more steel than this is necessary, it is fully as cheap to use structural steel columns based on 12,000 pounds per square inch and fireproof them. + +A 1–14–8 concrete should be used in columns with a 1–2–4 mix in the floor slab, as the confined 1–2–4 concrete in the floor slab through which the column passes has quite as much value as the 1–14–8 concrete midway between floors. + +Hooped columns based on Consideré's theory have been designed with as high a working stress as 1000 pounds per square inch, but in the light of experiments made at the Watertown Arsenal by United States Army engineers, such a working + +A REINFORCED CONCRETE CODE 27 + +stress does not seem rational, and the author would not advise the use of excessive values in compression until further investigation sufficiently warrants it. + +There is also an element of danger involved in carrying so high a compression value through the intersecting floor beams and girders with their many reinforcing rods around which it is necessary to use extreme care in the placing and tamping of concrete. + +**CONTINUITY OF MEMBERS.** In monolithic structures stresses are developed over all supports by the negative bending moments which must be taken care of by a sufficient quantity of steel to prevent cracks developing. In beams and girders, if one half the number of tension rods are trussed over the supports and lapped for a sufficient distance to develop their strength, all necessary provision is made against cracking of concrete over supports. All concrete liable to be affected by extreme temperature changes should be reinforced with steel to prevent cracks developing. + +In the case of floor slabs, the floor reinforcement should be kept down to within one inch of the bottom of the slab midway between beams and lifted to within one inch of the top of the slab over the beams. + +**BENDING MOMENTS.** In continuous beams, the maximum bending moment when adjacent spaces are loaded occurs over the supports. T-beam sections are designed for the maximum amount of steel at the bottom of the beam, midway between supports, this steel being balanced in compression by the T-section of concrete. The amount of steel thus obtained by using the formula $\frac{Wl}{8}$ is sufficient to relieve the stress over the columns and provide for any unequal loading of bays, the internal stresses adjusting themselves to the varied position of load. + +Some building ordinances allow the bending moment to be assumed $\frac{Wl}{10}$ with a maximum amount of steel over the columns. This is liable to cause a weakness in compression at the bottom of the beam next to the column before the strength of the steel is developed, unless the area of concrete at the bottom of the beam is increased by haunching the beam. + +The formula $\frac{Wl}{10}$ may be used for floor slabs when the reinforcement is lifted over the beams. + +CHAPTER IV + +REINFORCED CONCRETE SPECIFICATIONS + +**Cement.** The cement is to be stored in a suitable building and kept free from moisture before using. It is to be so placed as to admit identification and inspection of each shipment and so that the lots arriving first shall be used first. Cement shall be furnished at such periods that a seven-day test can be made on each lot before it is necessary for use. All cement shall be of a high grade American Portland, and shall comply with the specifications adopted by the American Society for Testing Materials. The cement tests shall be made as specified by persons skilled in this work, at the expense of the owner. + +All necessary assistance shall be provided the representative of the owner in obtaining such samples as he requires. + +**Sand.** The sand must be clean, sharp, and free from loam, clay, mica, or other objectionable material. Samples of the sand used shall be furnished the cement tester from time to time as required by the architect, so that the strength of a 1-3 mortar can be observed. + +**Crushed Stone or Gravel.** The crushed stone or gravel must be clean, hard, and free from foreign matter. Crushed slate, shale, or limestone shall not be used in reinforced concrete construction. + +Dust shall be screened out of crushed stone. Sand shall be screened out of gravel, but may be remixed with it in the proper proportions, if of the specified quality. + +For heavy foundations, stone which has passed through a 4-in. mesh may be used. For smaller footings and thick walls, stone which has passed through a 3-in. mesh may be used. For reinforced columns, girders, beams, slabs, and thin walls all stones shall pass through a 1-in. mesh. + +**Mixing.** Proper boxes or gauges must be provided for measuring sand and stone. 95 pounds of cement, or one bag, shall be assumed as .95 cubic feet. + +Concrete shall be mixed in an approved mixing machine, unless permission is obtained from the architect to mix by hand. + +In either case all concrete shall be mixed to his entire satisfaction, and no concrete shall be placed in the work until each particle of stone is thoroughly covered with mortar. + +Sufficient water is to be used to produce a “ wet ” mix, but not enough so that the concrete will be sloppy in the wheelbarrows with water standing at the top before depositing. + +Concrete is to be mixed in the following proportions: For the lower part of footings and for foundation walls, one part cement, two and one half parts sand, and five parts broken stone or gravel. For the upper part of footings and for columns, one part cement, one and one half parts sand, and three parts broken + +REINFORCED CONCRETE SPECIFICATIONS 20 + +stone. For all other reinforced work, one part cement, two parts sand, and four parts broken stone. Any variation from these materials or proportions must be with the written permission of the architect. + +PLACING CONCRETE. Concrete shall be deposited wet enough so that it will require but little tamping, but care must be taken in spading next to the forms to press back the stone and bring the mortar to the surface, so as to insure a smooth finish. Spading will also be necessary to bring the air bubbles to the surface, especially in deep columns. Columns for each floor shall be filled to the height of the bottom of the deepest intersecting beam or girder in two or more operations. After columns are filled sufficient time shall elapse before work is continued on the floor to allow shrinkage of concrete in columns to take place. The beams, girders, and floor slabs are to be laid as a monolith, and on no account shall work be stopped except on such lines as are previously determined or as directed at the time by the architect. As a general rule, working joints shall be through the middle of the bay. Joints where work is stopped are to be cleaned with a wire brush, and painted with a neat cement grout before any concrete is laid against them on resuming work. + +GRANOLITHIC SURFACES. Where granolithic surfaces are specified, the upper inch is to be composed of one part cement, three fourths part clean, sharp, coarse sand, and three fourths part crushed stone through a half-inch mesh with the dust screened out. + +It is preferable that this surface be laid monolithic with the floor slab, and if so it shall be part of the effective depth of the floor slab. If it is impracticable to lay the granolithic surface at the same time as the floor slab, then the total thickness of floor shall be increased one inch, and the granolithic surface shall be bonded to the base in an approved manner. The contractor must guarantee that the granolithic top shall not separate from the base for a period of one year from completion of work. + +Forms. Forms shall be constructed in a thorough and substantial manner and shall be well braced to prevent any distortion. All lumber adjacent to concrete shall be planed to uniform thickness, shall be laid with tight joints to prevent cement from escaping, and shall be free from shakes and loose knots. All floor boarding shall be laid in narrow widths of 6 inches or less, and special care must be taken to prevent uneven surfaces. Chamfer all corners of beams, girders, and columns by nailing triangular strips to the forms. A trap door shall be left at the bottom of each column form to admit cleaning out dirt before concrete is deposited. No forms shall be removed until the concrete is thoroughly set, and has obtained sufficient strength to prevent any distortion or deflection. After the forms are removed the contractor is to repair any defective work upon instruction by the architect, and if in his opinion such defects are sufficient to cause undue weakness, the whole of the member affected must be removed and replaced. After the forms are removed, cut off all fins, patch up defects, and correct other irregularities. + +REINFORCEMENT. The steel used for reinforcement shall consist of such shapes and sizes as are shown on the plans or approved by the architect. It shall conform to the "Manufacturers' Standard Specifications" for "Medium" steel. Under these specifications it may be either Bessemer or Open Hearth, although Open + +30 + +**PRACTICAL REINFORCED CONCRETE STANDARDS** + +*Hearth should be given the preference. It shall have an ultimate strength of 60,-000 to 70,000 pounds per square inch. It shall have an elastic limit of not less than half its ultimate strength. The percentage of elongation shall be 1,400,000 + ultimate strength. It shall bend 180 degrees to a diameter equal to thickness of piece tested, without fracture on outside of bent portion.* + +No steel used in reinforcing concrete shall be painted or coated with any oily material, but shall be clean and free from rust scales. + +Before placing, all steel shall be bent true to templates as required on the drawings. Care shall be taken in handling to preserve the shape of each piece, and in setting to place each piece or group of pieces in their proper locations. + +All steel reinforcement for columns, beams, and girders shall be assembled before being placed in the forms, in such a manner as to hold all component parts rigidly in their proper locations and to prevent any change in location of steel during the placing, tamping, or spading of the concrete. Rods shall be lapped 40 diameters over supports and dead ends shall be threaded and provided with two standard nuts including a 5-8 inch steel washer with an area of twenty-four times the sectional area of the rod or rods which it engages. + +PROTECTION AGAINST ELEMENTS. In hot weather concrete shall be kept wet one week after placing, and if possible covered from the sun's rays. + +Stone intended for use in concrete that has long been exposed to the sun shall be thoroughly wet down before using. + +Concrete shall be absolutely protected from freezing. Any concrete which has been allowed to freeze within forty-eight hours from the time of depositing shall be removed immediately and replaced with new concrete. + +--- + +**AMERICAN SOCIETY FOR TESTING MATERIALS** + +**REPORT OF COMMITTEE ON STANDARD SPECIFICATIONS FOR PORTLAND CEMENT** + +Adopted June 17, 1904 + +**GENERAL OBSERVATIONS** + +1. These remarks have been prepared with a view of pointing out the pertinent features of the various requirements and the precautions to be observed in the interpretation of the results of the tests. +2. The committee would suggest that the acceptance or rejection under these specifications be based on tests made by an experienced person having the proper means for making the tests. + +**SPECIFIC GRAVITY** + +Specific gravity is useful in detecting adulteration or underburning. The results of tests of specific gravity are not necessarily conclusive as an indication of the quality of a cement, but when in combination with the results of other tests may afford valuable indications. + +REINFORCED CONCRETE SPECIFICATIONS 51 + +**FINENESS** + +4. The sieves should be kept thoroughly dry. + +**TIME OF SETTING** + +5. Great care should be exercised to maintain the test pieces under as uniform conditions as possible. A sudden change or wide range of temperature in the room in which the tests are made, a very dry or humid atmosphere, and other irregularities, vitally affect the rate of setting. + +**TENSILE STRENGTH** + +6. Each consumer must fix the minimum requirements for tensile strength to suit his own conditions. They shall, however, be within the limits stated. + +**CONSTANCY OF VOLUME** + +7. The tests for constancy of volume are divided into two classes, the first normal, the second accelerated. The latter should be regarded as a precautionary test only, and not infallible. So many conditions enter into the making and interpreting of it that it should be used with extreme care. + +8. In making the pats the greatest care should be exercised to avoid initial strains due to molding or to too rapid drying-out during the first twenty-four hours. The pats should be preserved under the most uniform conditions possible, and rapid changes of temperature should be avoided. + +9. The failure to meet the requirements of the accelerated tests need not be sufficient cause for rejection. The cement may, however, be held for twenty-eight days, and a re-test made at the end of that period. Failure to meet the requirements at this time should be considered sufficient cause for rejection, although in the present state of our knowledge it cannot be said that such failure necessarily indicates unsoundness, nor can the cement be considered entirely satisfactory simply because it passes the tests. + +STANDARD SPECIFICATIONS FOR PORTLAND CEMENT + +**GENERAL CONDITIONS** + +1. All cement shall be inspected. +2. Cement may be inspected either at the place of manufacture or on the work. +3. In order to allow ample time for inspecting and testing, the cement should be stored in a suitable weather-tight building having the floor properly blocked or raised from the ground. +4. The cement shall be stored in such a manner as to permit easy access for proper inspection and identification of each shipment. +5. Every facility shall be provided by the contractor, and a period of at least twelve days allowed for the inspection and necessary tests. + +32 +PRACTICAL REINFORCED CONCRETE STANDARDS + +6. Cement shall be delivered in suitable packages with the brand and name of manufacturer plainly marked thereon. +7. A bag of cement shall contain 84 pounds of cement net. Each barrel of Portland cement shall contain 4 bags, and each barrel of natural cement shall contain 3 bags of the above net weight. +8. Cement failing to meet the seven-day requirements may be held awaiting the results of the twenty-eight-day tests before rejection. +9. All tests shall be made in accordance with the methods proposed by the Committee on Uniform Tests of Cement of the American Society of Civil Engineers presented to the Society January 21, 1903, and amended January 20, 1904, with all subsequent amendments thereto. (See addendum to these specifications.) +10. The acceptance or rejection shall be based on the following requirements: + +**PORTLAND CEMENT** + +**11. Definition.** This term is applied to the finely pulverized product resulting from the calcination to incipient fusion of an intimate mixture of properly proportioned argillaceous and calcareous materials, and to which no addition greater than 5 per cent. has been made subsequent to calcination. + +**SPECIFIC GRAVITY** + +12. The specific gravity of the cement, thoroughly dried at 100° C., shall be not less than 3.10. + +**FINENESS** + +13. It shall leave by weight a residue of not more than 8 per cent. on the No. 100, and not more than 25 per cent. on the No. 200 sieve. + +**TIME OF SETTING** + +14. It shall develop initial set in not less than thirty minutes, but must develop hard set in not less than one hour, nor more than ten hours. + +**TENSILE STRENGTH** + +15. The minimum requirements for tensile strength for briquettes one inch square in section shall be within the following limits, and shall show no retrogression in strength within the periods specified.* + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
AgeNeat CementStrength
24 hours in moist air150-200 lbs.
7 days (1 day in moist air, 6 days in water)450-550 **
28 days (1 day in moist air, 27 days in water)550-650 **
One Part Cement, Three Parts Sand
7 days (1 day in moist air, 6 days in water)150-200 **
28 days (1 day in moist air, 27 days in water)200-300 **
+ +*For example the minimum requirements for the twenty-four hour neat cement test should be some value within the limits of 150 and 200 pounds, and so on for each period stated. + +A page from a technical manual or standard document discussing Portland cement standards. + +REINFORCED CONCRETE SPECIFICATIONS + +CONSTANCY OF VOLUME + +16. Pats of neat cement about three inches in diameter, one half inch thick at the centre, and tapering to a thin edge, shall be kept in moist air for a period of twenty-four hours. + +(a) A pat is then kept in air at normal temperature and observed at intervals for at least twenty-eight days. + +(b) Another pat is kept in water maintained as near 70° F. as practicable, and observed at intervals for at least twenty-eight days. + +(c) A third pat is exposed in any convenient way in an atmosphere of steam, above boiling water, in a loosely closed vessel for five hours. + +17. These pats, to satisfactorily pass the requirements, shall remain firm and hard and show no signs of distortion, checking, cracking, or disintegrating. + +SULPHURIC ACID AND MAGNESIA + +18. The cement shall not contain more than 1.75 per cent. of anhydrous sulphuric acid (SO$_4$), nor more than 4 per cent. of magnesia (MgO). + +Submitted on behalf of the committee. +GEORGE F. SWAIN, Chairman. +GEORGE S. WEBSTER, Vice-Chairman. +RICHARD L. HUMPHREY, Secretary. + +ADDENDUM + +ABSTRACT OF METHODS RECOMMENDED BY THE SPECIAL COMMITTEE ON UNIFORM TESTS OF CEMENT OF THE AMERICAN SOCIETY OF CIVIL ENGINEERS + +SAMPLING + +1. **Selection of Sample.** The sample shall be a fair average of the contents of the package; it is recommended that, where conditions permit, one barrel in every ten be sampled. + +2. All samples should be passed through a sieve having twenty meshes per linear inch, in order to break up lumps and remove foreign material; this is also a very effective method for mixing them together in order to obtain an average. For determining the characteristics of a shipment of cement, the individual samples may be mixed and the average tested; where time will permit, however, it is recommended that they be tested separately. + +3. **Method of Sampling.** Cement in barrels should be sampled through a hole made in the centre of one of the staves, midway between the heads, or in the head, by means of an auger or a sampling iron similar to that used by sugar inspectors. If in bags, it should be taken from surface to centre. + +CHEMICAL ANALYSIS + +4. **Method.** As a method to be followed for the analysis of cement, that proposed by the Committee on Uniformity in the Analysis of Materials for the Port- + +54 +PRACTICAL REINFORCED CONCRETE STANDARDS + +land Cement Industry, of the New York Section of the Society for Chemical Indus- +try, and published in the Journal of the Society for January 15, 1902, is recom- +mended. + +SPECIFIC GRAVITY + +5. Apparatus and Method. The determination of specific gravity is most con- +veniently made with Le Chatelier's apparatus. This consists of a flask (D, Fig. 1) +of 120 cu. cm. (7.82 cu. ins.) capacity, the neck of which is about 20 cm. (7.87 ins.) +long; in the middle of this neck is a bulb (C), above and below which are +two marks, $F$ and $E$; the volume between these marks is 20 cu. cm. +(1.82 cu. ins.). The neck has a diameter of about 9 mm. (0.35 in.), and +is graduated into tenths of cubic centimeters above the mark $F$. + +6. Benzine (68° Baumé), naphtha, or kerosene free from water, should be +used in making the determination. + +7. The specific gravity can be deter- +mined in two ways: + +(1) The flask is filled with either of +these liquids to the lower mark ($E$), +and 64 gr. (2.25 oz.) of powder, pre- +viously dried at 100° C. (212° F.) and +cooled to the temperature of the liquid, +is gradually introduced through the +funnel ($B$) [the stem of which extends into the flask to the top of the bulb ($C$)], +until the upper mark ($F$) is reached. The difference in weight between the cement +remaining and the original quantity (64 gr.) is the weight which has displaced +20 cu. cm. + +8. (2) The whole quantity of the powder is introduced, and the level of the liquid +rises to some division of the graduated neck. This reading plus 20 cu. cm. is the +volume displaced by 64 gr. of the powder. + +9. The specific gravity is then obtained from the formula: + +$$\text{Specific Gravity} = \frac{\text{Weight of Cement}}{\text{Displaced Volume}}$$ + +10. The flask, during the operation, is kept immersed in water in a jar ($A$), in +order to avoid variations in the temperature of the liquid. The results should agree +within 0.01. + +11. A convenient method for cleaning the apparatus is as follows: The flask is +inverted over a large vessel, preferably a glass jar, and shaken vertically until the +liquid starts to flow freely; it is then held still in a vertical position until empty; +the remaining traces of cement can be removed in a similar manner by pouring into +the flask a small quantity of clean liquid and repeating the operation. + +Fig. 1.—Le CHATELIER'S SPECIFIC GRAVITY APPARATUS + +REINFORCED CONCRETE SPECIFICATIONS 35 + +**FINENESS** + +12. **Apparatus.** The sieves should be circular, about 20 cm. (7.87 ins.) in diameter, 6 cm. (2.36 ins.) high, and provided with a pan 5 cm. (1.97 ins.) deep, and a cover. + +13. The wire cloth should be woven (not twilled) from brass wire having the following diameters: + +No. 100, 0.0045 in.; No. 200, 0.0024 in. + +14. This cloth should be mounted on the frames without distortion; the mesh should be regular in spacing and be within the following limits: + +No. 100, 96 to 100 meshes to the linear inch. +No. 200, 188 to 200 “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ “ + +15. Fifty grams (1.76 oz.) or 100 gr. (3.52 oz.) should be used for the test, and dried at a temperature of 100° C. (412° F.) prior to sieving. + +16. **Method.** The thoroughly dried and coarsely screened sample is weighed and placed on the No. 200 sieve, which, with pan and cover attached, is held in one hand in a slightly inclined position, and moved forward and backward, at the same time striking the side gently with the palm of the other hand, at the rate of about 300 strokes per minute. The operation is continued until not more than one tenth of 1 per cent. passes through after one minute of continuous sieving. The residue is weighed, then placed on the No. 100 sieve and the operation repeated. The work may be expedited by placing in the sieve a small quantity of large shot. The results should be reported to the nearest tenth of 1 per cent. + +**NORMAL CONSISTENCY** + +17. **Method.** This can best be determined by means of *Vicat Needle Apparatus*, which consists of a frame (*K*), Fig. 2, bearing a movable rod (*L*), with the cap (*A*) at one end, and at the other the cylinder (*B*), 1 cm. (0.39 in.) in diameter, the cap, rod and cylinder weighing 800 gr. (10.58 oz.). The rod, which can be held in any desired position by a screw (*F*), carries an indicator, which moves over a scale (graduated to centimeters) attached to the frame (*K*). The paste is held by a conical, hard-rubber ring (*I*), 7 cm. (2.76 ins.) in diameter at the base, 4 cm. (1.57 ins.) high, resting on a glass plate (*J*) about 10 cm. (3.94 ins.) square. + +Fig. 2.—VICAT NEEDLE + +18. In making the determination, the same quantity of cement as will be subsequently used for each batch in making the briquettes (but not less than 500 grams) is kneaded into a paste, as described + +36 +PRACTICAL REINFORCED CONCRETE STANDARDS + +in paragraph 89, and quickly formed into a ball with the hands, completing the operation by tossing it six times from one hand to the other, maintained 6 ins. apart; the ball is then pressed into the rubber ring, through the larger opening, smoothed off, and placed (on its large end) on a glass plate and the smaller end smoothed off with a trowel; the paste, confined in the ring, resting on the plate, is placed under the rod bearing the cylinder, which is brought in contact with the surface and quickly released. + +19. The paste is of normal consistency when the cylinder penetrates to a point in the mass 10 mm. (0.39 in.) below the top of the ring. Great care must be taken to fill the ring exactly to the top. + +20. The trial pastes are made with varying percentages of water until the correct consistency is obtained. + +PERCENTAGE OF WATER FOR STANDARD MIXTURES¹ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Neat1-11-31-51-41-6Neat1-11-31-51-41-6
1812.010.09.08.48.03317.013.311.510.49.6
1912.310.29.28.58.13417.313.611.710.59.7
2012.710.49.38.78.23517.713.811.810.79.9
2113.010.79.58.88.33618.014.012.010.810.0
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+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +REINFORCED CONCRETE SPECIFICATIONS 57 + +800 gr. (10.58 oz.). The needle is then carefully brought in contact with the surface of the paste and quickly released. + +23. The setting is said to have commenced when the needle ceases to pass a point 5 mm. (0.80 in.) above the upper surface of the glass plate, and is said to have terminated the moment the needle does not sink visibly into the mass. + +24. The test pieces should be stored in moist air during the test; this is accomplished by placing them on a rack over water contained in a pan and covered with a damp cloth, the cloth to be kept away from them by means of a wire screen; or they may be stored in a moist box or closet. + +25. Care should be taken to keep the needle clean, as the collection of cement on the sides of the needle retards the penetration, while cement on the point reduces the area and tends to increase the penetration. + +26. The determination of the time of setting is only approximate, being materially affected by the temperature of the mixing water, the temperature and humidity of the air during the test, the percentage of water used, and the amount of molding the paste receives. + +STANDARD SAND + +27. For the present, the Committee recommends the natural sand from Ottawa, Ill., screened to pass a sieve having 20 meshes per linear inch and retained on a sieve having 30 meshes per linear inch; the wires to have diameters of 0.0165 and 0.0112 in., respectively, i. e. half the width of the opening in each case. Sand having passed the No. 30 sieve shall be considered standard when not more than 1 per cent. passes a No. 30 sieve after one minute continuous sifting of a 500-gram sample. + +28. The Sandusky Portland Cement Company, of Sandusky, Ohio, has agreed to undertake the preparation of this sand and to furnish it at a price only sufficient to cover the actual cost of preparation. + +FORM OF BRIQUETTE + +29. While the form of the briquette recommended by a former committee of the Society is not wholly satisfactory, this committee is not prepared to suggest any change, other than rounding off the corners by curves of ½-in. radius, Fig. 3. + +Fig. 3.—Details for Briquette + +58 +PRACTICAL REINFORCED CONCRETE STANDARDS + +MOLDS + +30. The molds should be made of brass, bronze, or some equally non-corrodible material, having sufficient metal in the sides to prevent spreading during molding. + +A diagram showing a gang mold with multiple compartments for holding and pressing briquettes. + +Fig. 4. — DETAILS FOR GANG MOLD + +31. Gang molds, which permit molding a number of briquettes at one time, are preferred by many to single molds; since the greater quantity of mortar that can be mixed tends to produce greater uniformity in the results. The type shown in Fig. 4 is recommended. + +32. The molds should be wiped with an oily cloth before using. + +MIXING + +33. All proportions should be stated by weight; the quantity of water to be used should be stated as a percentage of the dry material. + +34. The metric system is recommended because of the convenient relation of the gram and the cubic centimeter. + +35. The temperature of the room and the mixing water should be as near 21° C. (70° F.) as it is practicable to maintain it. + +36. The sand and cement should be thoroughly mixed dry. The mixing should be done on some non-absorbing surface, preferably plate glass. If the mixing must be done on an absorbing surface it should be thoroughly dampened prior to use. + +37. The quantity of material to be mixed at one time depends on the number of test pieces to be made; about 1000 gr. (35.48 oz.) makes a convenient quantity to mix, especially by hand methods. + +38. Method. The material is weighed and placed on the mixing table, and a crater formed in the centre, into which the proper percentage of clean water is poured; the material on the outer edge is turned into the crater by the aid of a trowel. As soon as the water has been absorbed, which should not require more than one minute, the operation is completed by vigorously kneading with the hands for an additional 1/2 minutes, the process being similar to that used in kneading dough. A sand-glass affords a convenient guide for the time of kneading. During the operation of mixing, the hands should be protected by gloves, preferably rubber. + +MOULDING + +39. Having worked the paste or mortar to the proper consistency, it is at once placed in the molds by hand. + +40. Method. The molds should be filled at once, the material pressed in firmly with the fingers and smoothed off with a trowel without ramming; the material should be heaped up on the upper surface of the mold, and in smoothing off, the trowel should be drawn over the mold in such a manner as to exert a moderate pressure on the excess material. The mold should be turned over and the operation repeated. + +REINFORCED CONCRETE SPECIFICATIONS 39 + +41. A check upon the uniformity of the mixing and molding is afforded by weighing the briquettes just prior to immersion, or upon removal from the moist closet. Briquettes which vary in weight more than 5 per cent. from the average should not be tested. + +STORAGE OF THE TEST PIECES + +42. During the first twenty-four hours after molding, the test pieces should be kept in moist air to prevent them from drying out. + +43. A moist closet or chamber is so easily devised that the use of the damp cloth should be abandoned, if possible. Covering the test pieces with a damp cloth is objectionable, as commonly used, because the cloth may dry out unequally, and in consequence the test pieces are not all maintained under the same condition. Where a moist closet is not available, a cloth may be used and kept uniformly wet by immersing the ends in water. It should be kept from direct contact with the test pieces by means of a wire screen or some similar arrangement. + +44. A moist closet consists of a soapstone or slate box, or a metal-lined wooden box — the metal lining being covered with felt and this felt kept wet. The bottom of the box is so constructed as to hold water, and the sides are provided with cleats for holding glass shelves on which to place the briquettes. Care should be taken to keep the air in the closet uniformly moist. + +45. After twenty-four hours in moist air, the test pieces for longer periods of time should be immersed in water maintained as near $21^{\circ}$ C. ($70^{\circ}$ F.) as practicable; they may be stored in tanks or pans, which should be of non-corrodible material. + +TENSILE STRENGTH + +46. The tests may be made on any standard machine. A solid metal clip, as shown in Fig. 5, is recommended. This clip is to be used without cushioning at the points of contact with the test specimen. The bearing at each point of contact should be $\frac{1}{4}$ in. wide, and the distance between the centre of contact on the same clip should be $1\frac{1}{4}$ in. + +Fig. 5.—Form of Clip + +40 + +**PRACTICAL REINFORCED CONCRETE STANDARDS** + +47. Test pieces should be broken as soon as they are removed from the water. Care should be observed in centring the briquettes in the testing machine, as cross-strains, produced by improper centring, tend to lower the breaking strength. The load should not be applied too suddenly, as it may produce vibration, the shock from which often breaks the briquette before the ultimate strength is reached. Care must be taken that the clips and the sides of the briquette be clean and free from grains of sand or dirt, which would prevent a good bearing. The load should be applied at the rate of 600 lbs. per minute. The average of the briquettes of each sample tested should be taken as the test, excluding any results which are manifestly faulty. + +**CONSTANCY OF VOLUME** + +48. **Methods.** Tests for constancy of volume are divided into two classes: +(1) normal tests, or those made in either air or water maintained at about $21^{\circ}$ C. ($70^{\circ}$ F.), and (2) accelerated tests, or those made in air, steam, or water at a temperature of $45^{\circ}$ C. ($115^{\circ}$ F.) and upward. The test pieces should be allowed to remain twenty-four hours in moist air before immersion in water or steam, or preservation in air. + +49. For these tests, pats about $\frac{7}{4}$ cm. (2.95 ins.) in diameter, 1$\frac{3}{4}$ cm. (0.49 ins.) thick at the centre, and tapering to a thin edge, should be made, upon a clean glass plate [about 10 cm. (3.94 ins.) square], from cement paste of normal consistency. + +50. **Normal Test.** A pat is immersed in water maintained as near $21$ C. ($70^{\circ}$ F.) as possible for twenty-eight days, and observed at intervals. A similar pat is maintained in air at ordinary temperature and observed at intervals. + +51. **Accelerated Test.** A pat is exposed in any convenient way in an atmosphere of steam, above boiling water, in a loosely-closed vessel. + +52. To pass these tests satisfactorily, the pats should remain firm and hard, and show no signs of cracking, distortion, or disintegration. + +53. Should the pat leave the plate, distortion may be detected best with a straight-edge applied to the surface which was in contact with the plate. + +CHAPTER V + +FOUNDATIONS + +LOADING + +The floor slabs, beams, and girders throughout a building should be designed for full dead and live load. + +It is considered safe by many architects and engineers to make reductions from column loading from floor to floor, on the assumption that the entire space of any one floor will not be loaded to its full capacity. The recommendation for floor loads by a committee of Boston engineers acting as a commission on the revision of the building laws is as follows: "All new or renewed floors shall be so constructed as to carry safely the weight to which the proposed use of the building will subject them, and every permit granted shall state for what purpose the building is designed to be used; but the least capacity per superficial square foot, exclusive of materials shall be: + +" For floors of houses for habitation, fifty pounds. +"For office floors and for public rooms of hotels and houses exceeding five hundred square feet, one hundred pounds. +"For floors of retail stores and public buildings, except schoolhouses, one hundred and twenty-five pounds. +"For floors of schoolhouses, other than floors of assembly rooms, eighty pounds, and for floors of assembly rooms, one hundred and twenty-five pounds. +"For floors of drill rooms, dance halls, and riding schools, two hundred pounds. +"The floors of warehouses and mercantile buildings, at least two hundred and fifty pounds. +"The loads for floors not included in this classification or for galleries shall be determined by the commissioner. + +"The full floor load specified in this section shall be included in proportioning all parts of buildings designed for warehouses, or for heavy mercantile and manufacturing purposes. In other buildings, however, certain reductions may be allowed as follows: In girders carrying more than one hundred square feet of floor, the live load may be reduced ten per cent. In columns, piers, walls, and other parts carrying two floors, a reduction of fifteen per cent. of the total live load may be made; where three floors are carried the total live load may be reduced by twenty per cent.; four floors, twenty-five per cent.; five floors, thirty per cent.; six floors, thirty-five per cent.; seven floors, forty per cent.; eight floors, forty-five per cent.; nine or more floors, fifty per cent. + +"The platforms, landings, and stairways of every fire escape shall be strong enough to carry a load of seventy pounds to the square foot in addition to the weight of material." + +42 +PRACTICAL REINFORCED CONCRETE STANDARDS + +The foundations should be so designed as to carry the load transmitted to them by the columns, with an equal loading per square foot of bearing area for both interior and exterior footings, in order to prevent cracks that might be occasioned by any unequal settlements. + +CLASSES OF FOUNDATIONS + +Foundations are usually supported in two ways, either directly upon the soil or upon piles. + +Borings or test pits should be made for every job of any importance, to determine the character of the soil, as there often may be strata of soft material underlying a hard surface material. + +Pile foundations should be used wherever there is any question as to the bearing value of the soil being inadequate to the load. + +The foundation of any structure is the last place to apply economy. + +The cost of pile foundations will not average four per cent. of the cost of any ordinary building, and it would seem unwise to jeopardize ninety-six per cent. to save four per cent. + +FOUNDATIONS DIRECTLY UPON THE SOIL. These are divided into two classes, plain foundations and grillage foundations. + +The plain foundations do not generally require any great amount of engineering. The area of the footing should be such as to conform to the bearing value of the soil, which should be predetermined, and the depth should be at least one and one half times the projection from side of bearing area above, or $b - \frac{3a}{2}$ (see cut). + +Footings may be built up in successive steps or in the shape of a truncated pyramid. The first method is the more economical owing to the simplicity of forms. It is difficult to keep the forms in position for the second method, as a mass of wet concrete deposited in them is liable to float them. + +The concrete in the lower part of the footing should not be weaker than 1–3–6, and the upper portion must be of the same mixture as a supported concrete column. Where an iron bearing plate is used under a cast iron or steel column, its area must be such that the safe working strength of the concrete directly under it is not exceeded. + +Whenever eccentricity of loading occurs, it should be properly taken care of in the design and the error should be guarded against of assuming the maximum load per square foot over the full bearing area. + +When a great amount of excavation is necessary to carry footings to a satisfactory foundation, an economical method is to excavate inside a steel shell driven into the ground as the excavation progresses,—this excavation to be enlarged at the bottom of the shell to obtain the required bearing area. The full size of excavation is filled with concrete as soon as the excavation is completed. + +FOUNDATIONS WITH STEEL GRILLAGE. The advantages of this type of founda- + +FOUNDATIONS 43 + +tion are in the saving of excavation, and in many cases shoring and pumping, also in obtaining a large bearing area on a poor soil. There is a considerable saving in labor and concrete materials with this method, but this saving in cost is usually balanced by the cost of the steel grillage. + +Grillage foundations are especially adapted for chimneys, where it is desirable to obtain a uniform distribution of stress over a large area. + +Mr. E. L. Ransome has published formulae for this type of foundation which have been extensively used and are reprinted with his permission. + +WALL AND PIER FOOTINGS + +Figures 1 and 2 illustrate the general form and arrangement of tension bars in our standard wall and pier footings. + +FORMULA FOR WALL FOOTINGS + +We have given in all cases the width of the wall ($W$), the load per linear foot ($L$), and the width of the footing ($D$). The total stress in the tension bars or the total compression in the concrete per linear foot is + +$$\text{Stress} = \frac{2LP}{7D},$$ + +in which $L$ equals the total load in tons, $P$ equals the projection in inches, and $D$ equals the distance in inches from the top of the footing to the centre of the bars. + +We have two unknown quantities, Stress and $D$. It is therefore unnecessary to impose another condition, and it is that when the safe compressive strength of the concrete equals 35 tons per square foot there shall be 16 square inches of concrete in the area above the bars for each ton stress or $16 \times \text{Stress} = 12 \times D$, from which $\text{Stress} = \frac{1}{4}D$. + +This condition is necessary in order that the concrete shall not be strained beyond its safe compressive strength, and should be modified to suit this strength when the latter does not conform to the value of 35 tons. Substituting this value of Stress in the above formula and reducing, we have $D$ equals the square root of $\frac{8LP}{21}$. + +Having obtained $D$ from this formula, the total stress in the bars in tons = $\frac{1}{4}D$. The bars may be placed as shown on plan. The size of the bars should be so taken that the bars will not be spaced more than 12 inches apart. The total height ($H$) of the footing should be at least 5 inches greater than the depth ($D$). + +Section through wall footing +Plan of wall footing +**Fig. 1** + +44 + +**PRACTICAL REINFORCED CONCRETE STANDARDS** + +**Example:** Let $W = 2$ feet. Load = 80 tons per lin. ft. and Safe Bearing Power of Soil = 2 tons. Then $W_1 = 10$ feet and $P = 4$ feet. $D$ equals the square root of $8 \times 20 \times 48$ in. = 19 inches. And Stress = $\frac{4}{3} \times 19 = 14.33$ tons, requiring $\frac{4}{3}$-inch square bars $\frac{4}{3}$ inches on centres. Their length would be $W_1 - P = 8$ feet. + +**II. FORMULA FOR PIER FOOTINGS** + +As in the case for Wall footings, we have given the dimensions of the supported pier and footing ($W$ and $W_1$) and the total load carried ($L$). + +Our formula for obtaining the Stress in the tension bars running in each direction is + +$$\frac{L \times P}{8 \times D}$$ + +in which we have as before the two unknown quantities Stress and $D$. In order that the concrete may not be compressed beyond its safe working strength, we impose the condition + +$$4 \times \text{Stress} = \frac{D \times (W + 6)}{8}$$ + +from which + +$$\text{Stress} = \frac{D \times (W + 6)}{8}$$ + +Substituting this value of Stress in the above formula and reducing, we have $D$ equals the square root of $\frac{8 \times L \times P}{(W + 6)}$. Having obtained $D$ by this formula, the total Stress in tons equals $\frac{W + 6}{8} \times D$, from which the size and number of bars running in each direction can be computed. These bars may be made in two lengths as shown on plan, Fig. 2, the shorter length being equal to $W + P$. The total height ($H$) should not be less than $D + 4$ inches. + +**Example:** Let $W = 16$ inches. Load = 80 tons. Safe bearing power of soil = 2 tons. The required area of base of footing is 40 square feet, and the width ($W_1$) equals the square root of 40 - 6 feet = 7 inches. + +$$D = \sqrt{\frac{8 \times 90 \times 30}{3 \times 22}} = 17$$ inches. The total stress would therefore be $$\frac{22}{8} \times 17 - 47$$ tons requiring 9 $\frac{4}{3}$-inch bars or 19 $\frac{4}{3}$-inch bars in each direction. + +Fig. 2 +PLAN OF PIER FOOTING + +FOUNDATIONS 45 + +These bars should be spaced equally over $W \cdot D$. The total height ($H$) would be $D + 4$ inches. + +In the examples given by Mr. Ransome he has used the square twisted bar, for which he has assumed a working strength of 20,000 pounds per square inch. + +**FOUNDATIONS ON PILES** + +There are two classes of pile foundations: + +*First:* where the piles pass through a soft material to a hard underlying strata. +*Second:* Where the piles are sustained by friction or suction and do not reach a point where the penetration is suddenly arrested. + +Wooden piles are more generally used, although there are several types of concrete piles. As a rule, however, concrete piles cannot be used to advantage for lengths of over 25 or 30 feet, and the economy in their use consists in the saving of the excavation and the placing of heavy concrete foundations which would be necessary where wood piles must be cut off at a low grade. + +A great many claims have been made as to the superior supporting value of concrete piles over wooden piles. The testimony supporting these claims has been mostly submitted by interested parties, and the author recommends that a thorough investigation of the character of the soil, the design and size of the pile, and the method of driving be made before the supporting value of the pile is fixed. + +**PENETRATION OF WOODEN PILES** + +In the first class of pile foundations the penetration due to a 2000-pound hammer falling ten feet should not be over one inch for the last blow, and if the penetration does not exceed this a safe load of 16 tons per pile may be assumed. In the second class an ordinary rule is that the penetration under the same hammer and drop shall not be over three inches for the last blow, and that a safe load of 10 tons per pile may be assumed. + +There has been considerable discussion in regard to this rule, inasmuch that it makes no account of the frictional resistance of piles of different sizes. + +W. M. Patton in his "Practical Treatise on Foundations" suggests a formula for frictional resistance of piles made up as follows: + +$$S = (W - P) + F$$ + +where + +- $S$ = square feet of surface of pile in contact with soil. +- $W$ = load on pile. +- $P$ = bearing power of soil per square foot. +- $F$ = working value of friction of soil on superficial area of pile, per square foot. + +$P$ is the safe loads for various soils in the following table, and may be neglected in loose soils, as its proportional value is small. + +
+ + + + + + + + + + + + + + + + + + + + +
Ledge Rock86 tons per square foot.
Hard pan8
Gravel5
Clean sharp sand4
Dry clay3
+ +46 +PRACTICAL REINFORCED CONCRETE STANDARDS + +Wet clay 2 tons per square foot. +Loam 1 " " " " " " " +F will vary from 50 to 150 pounds per square foot for soft semi-fluid soils, varying with their consistency; from 150 to 250 pounds per square foot for mixed earths and gritty soils, and from 200 to 300 pounds per square foot for compact clays, sand, and gravel. + +In the eastern section of the United States, spruce piles are the cheapest. They are cut in lengths of from 30 to 50 feet, and measure from 4 to 6 inches at the tip and from 10 to 14 inches at the head. + +For the first class of foundations the diameter of tip only should be specified, and it should not be less than 6 inches under the bark. + +For the second class, where friction is depended upon almost wholly, the size of the tip is of not so much importance, and the size of the head should be specified not less than 11 inches. + +It is necessary sometimes to use a greater length of pile than can be obtained in spruce. Hard pine, Norway pine, or chestnut piles can be obtained in lengths up to 78 or 80 feet with a head diameter of approximately 16 inches. + +CUTTING OFF PILES + +Piles should be cut off at a grade where the soil is constantly wet, as an alternately wet and dry condition will inevitably cause decay. + +Where piles are exposed to tide water by filtration through the soil, it is customary to specify cutting them off at half tide level. + +In clay or muck which does not permit the water to escape readily on a receding tide, the piles may be cut off at a foot or two higher level without danger of decay. Many cities and towns have ordinances requiring piles to be cut off at certain fixed grades which must be complied with. + +SPACING OF PILES + +In hard soils piles may be spaced as closely together as 2 feet 6 inches on centres. In soft soils they should be spaced 5 feet or 3 feet 6 inches on centres. Heads of piles should be encased in concrete capping. + +Save all piles off in each footing either at the specified grade or lower if necessary, to cut out any broomed or damaged heads. Excavate around piles to a depth of 6 inches below top of pile and see that tops of piles are clean and that dirt is rammed solidly around them before concrete is deposited. The concrete should be of sufficiently rich mixture so that no load carried on the head of the pile does not exceed the safe compressive strength of the concrete. + +For example. A pile with a 11-inch diameter head supports 16 tons or $2,000 pounds. The area of the head is approximately 85 square inches. $2,000 divided by 85 equals 270 pounds per square inch. The concrete capping in this case should not be leaner than 1-24-5. + +SIMPSON BROS. +CORPORATION +Engineers and Contractors + +REINFORCED CONCRETE.—Foundations, +Buildings, Bridges, Tanks, etc. +CONCRETE MASONRY. +GRANOLITHIC Walks, Driveways, Steps, etc. +ARTIFICIAL STONE-WORK of every description. +NEUCHATEL or SEYSSEL Rock Asphalt for +Basements, Laundries, Stables, Stores, Brew- +eries, Dye-Houses, Mills, etc., laid on wood or +cement. +TAR CONCRETE Walks and Driveways. +SANITARY (Plastic) Floors for Bathrooms, +Kitchens, Schools, Hospitals, etc. +HASSAM (Concrete) STREET PAVEMENT. +Manufacturers of SIMBROCO Concrete Blocks, +and Cast Stone for Buildings and Building Trim. + +166 Devonshire Street, Room 58 +BOSTON, MASSACHUSETTS +(Only New England Business Desired) + +1 + +**"AGRIPPA" SEPARATOR-CLAMP** +FOR BEAM AND GIRDER REINFORCEMENT + +A diagram showing the "AGRIPPA" separator-clamp system. It shows a beam with rods inserted into the separator-clamp, which is then placed on the floor alongside the beams. The concrete is poured around the rods, and the clamp is removed after the concrete has set. + +The necessity of keeping steel reinforcement in the position designed is recognized by all engineers and architects. The cut above shows the simplest and most economical form that can be devised for this purpose. + +Our "Agrippa" separator-clamp admits using any type of rod. +Steel may be bought in the open market, and assembled on the floor alongside of the beams. + +When it is placed in the beams, after assembling, the concrete may be poured and tamped around it without danger of displacement. + +It is not necessary to pay exorbitant prices for the patented "systems" of reinforcement to get this result. + +"The Agrippa" separator-clamp saves time, worry and money. +We have laid 9000 square feet of floor, including girders and beams in sixteen hours without a man on steel reinforcement after beginning concrete work. +Provides means for hanging shafting, piping, etc. + +SEPARATOR-CLAMPS OR PATENT RIGHTS FOR SALE BY +**SIMPSON BROS. CORPORATION** +166 DEVONSHIRE ST. +BOSTON, MASS. + +2 + +THE STANDARD AMERICAN BRAND +Atlas Portland Cement +ALWAYS UNIFORM +Productive Capacity over +40,000 Barrels per Day +"Atlas" Portland Cement is manufactured from +the finest raw materials, under expert supervision +in every department of the works, and is specified +by leading engineers in the United States. +Write us for publications on concrete construction +THE ATLAS PORTLAND CEMENT CO. +30 Broad Street, New York City + +Waldo Brothers +(C. S. WALDO, Sole Proprietor) +102 Milk Street, +BOSTON +New England Distributors +ATLAS PORTLAND CEMENT +Agents for WHITE PORTLAND CEMENT and +WATERPROOFING COMPOUND + +3 + +JAMES A. DAVIS & CO. +SOLE N. E. AGENTS + +Lehigh Portland Cement + +STANDARD FOR QUALITY +"BLANC" STAINLESS CEMENT + +THE Best White Cement in the world. A true Portland, and perfectly white. Write us for particulars and prices. Ex- tensively used in Government buildings at Washington, D.C. for floors and ornamental work. + +OFFICES: +92 State Street, Boston + +TELEPHONE CONNECTIONS WITH EVERYWHERE + +4 + +A vintage illustration of a building with a prominent clock tower and a large, ornate entrance. +REINFORCED CONCRETE STABLE, WITH ASBESTOS "CENTURY" SHINGLE ROOF, BUILT BY SIMPSON BROS CORPORATION FOR THEODORE M. DAVIE, NEWPORT, R. I. + +**Asbestos "Century" Shingles** +"The Roof that Outlives the Building" + +Asbestos "Century" Shingles, the most perfect indestructible roofing, is made of asbestos fibre and hydraulic cement, compressed into thin sheets under enormous hydraulic pressure. The cement hydrates and crystallizes around the asbestos fibre, growing more and more hard and elastic with age. Asbestos "Century" Shingles are fire-proof and climate proof. They do not flake off or split at the nail holes. Applied like any shingle or slate. An Asbestos "Century" Shingle roof will outlive the building, without painting or repairs. + +A great variety of shapes, in several sizes and three colors — Newport Gray (light), Slate (blue black), and Indian Red. Five cents per square foot at Ambler, Pennsylvania, is the base price without lap. + + + + + + + +
Asbestos "Century" ShinglesAsbestos Building LumberReinforced Asbestos Corrugated Sheathing
+ +The Keasbey & Mattison Co. +FACTORS +Ambler, Pennsylvania + +5 + +FLOORS +NOTE CONTINUOUS BOND +Roofs + +# Ne Entire Collapse of any Arch Reinforced with CLINTON WELDED WIRE can occur + +unless the weight imposed upon the arch is sufficient to strain and break all of the wires. + +This is due to the fact that Clinton Welded Wire, made from 6 to 10 gauge drawn steel wire, galvanized or plain, can be laid in lengths up to 300 feet, thereby forming a continuous bond for that distance. In a building 200 feet long, for instance, our reinforcing is secured at the front or rear of the building, and carried through the entire distance without a break. Heavier gauge wire will be laid in lengths up to 150 feet and locked or hooked to the next sheet, where building requires more than one sheet in length. + +**The Continuous Bond of Clinton Electrically Welded Wire is the ONE best Reinforcing for Concrete** + +**CLINTON WIRE CLOTH COMPANY** +**CLINTON, M.ASS.** + +--- + +**FIREPROOFING DEPARTMENTS** +**ALBERT OLIVER, 1 Madison Avenue, New York** + +WASHINGTON — BURLING SUPPLY CO., Denver Bldg. +CHICAGO — CLINTON WIRE CLOTH CO., 32 River St. +ST. LOUIS — HUNTER-MILLER LINE & GUYERT CO. +BOSTON — BURTON & CO., 17-21 Hanover St. +SAN FRANCISCO — L. A. GORRIN, 55 Broadway Bldg. +BROOKLYN, N. Y. — PARAGON PLANTER CO. +CLEVELAND — CARL HORNE, 429 Garfield Building + +--- + +CEILINGS + +PARTI- +TIONS + +6 + +A building with a brick facade and a clock tower. +**BAY STATE BRICK and CEMENT COATING** +**PROTECTS AND DECORATES CONCRETE, BRICK AND PLASTER SURFACES** + +BAY STATE BRICK and CEMENT COATING is the ORIGINAL COATING for Concrete, Brick, and Plaster on both interior and exterior surfaces. It can be applied to CONCRETE and PLASTER which are not completely dried out and ONE COAT covers better than two coats of lead and oil paints without the danger of peeling. It does not deteriorate the concrete mixture as do dry colors mixed with the cement. It makes a splendid hard baked finish which will last indefinitely. It is made in WHITE and COLORS. It provides the only way to decorate such surfaces with UNIFORM and harmonious color. Made only in LIQUID FORM, ready for use (never made in paste form). Booklet free giving specifications, names of specifying architects throughout the country and cuts of nice houses where used. + +Made only by +**WADSWORTH, HOWLAND & CO., Inc.** +**PAINT AND UARNISH MAKERS** +82 and 84 Washington Street, Boston, Mass. + +--- + +**A. W. HASTINGS & CO.** +**BOSTON, MASS.** +**134 to 142 Friend Street** + +**DOORS, FRAMES, AND SASH** + +Window Frames especially constructed for Concrete Buildings + +--- + +BELOW WE NAME A FEW BUILDINGS FURNISHED BY US + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Boston Woven HouseCambridge 3 Bldgs.Beilley Auto Co.Springfield
H. M. Sawyer FactoryCambridgeH. F. & E. D.Seymour, Conn.
Simples Electric Co.CambridgeFranklin Yere Co.Franklin
Torrey & Co.'sBoston 2 Bldgs.Henry HubbellBridgeport, Conn.
Lockport Block Co.East BostonTeles Mfg. Co.Medford
Lumeden and Van StoneSouth BostonLydiar Confectionery Co.Cambridge
American Meter Co.Albany, N. Y.Stetson Shoe Co.Weymouth
+ +AND MANY OTHERS + +7 + +The Riverside Press +CAMBRIDGE - MASSACHUSETTS +U.S.A + +--- \ No newline at end of file