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AWWA C401-64 (Formerly AWWA H2) American Water Works Association STANDARD PRACTICE FOR THE SELECTION OF ASBESTOS-CEMENT WATER PIPE Approved by the AWWA Board of Directors, Jan. 27, 1964 AMERICAN WATER WORKS ASSOCIATION Incorporated 2 Park Avenue, New York, N.Y. 10016 Prepared by AWWA Committee on Asbestos-Cement Water Pipe E. H. Aldrich F. G. Denson C. R. Erickson J. E. Farrell R. H. Ritter, Chairman W. R. Gelston R. H. Jensen K. A. McCord X. D. Murden Producers J. R. Cran C. R. Meek <0 Copyright 1964 by the American Water Works Association, Inc. as part of the May 1964 JOURNAL American Water Works Association Made in USA Second Printing, May 1966 ii Table of Contents Section Scope............................................................. 1 Strength and Design Factors.....................2 Bedding Conditions............................. 3 Combined-Loading Theory.......................... 4 Three-Edge-Bearing Load Factors .... S Appendix................ Section Hydrostatic Pressures .............................. 6 External Loads .......................................... 7 Safety Factors ........................................... 8 Selection Curves ..........................................9 References................................... follozmng 9 .following References in Standard Practice for the Selection of Asbestos-Cement Water Pipe Sec. 1--Scope This handbook has been prepared so that design engineers may quickly de termine the correct class of asbestoscement pipe to use under various com binations of internal pressure and ex ternal loading. Curves are included in this handbook to expedite the selec tion of the correct pipe class. De tailed analyses of the various struc tural factors affecting pipe design and selection are treated under separate headings. Pipe pressure designations of Class 100, Class ISO, and Class 200 in this handbook refer to the similarly num bered classes specified in AWWA C400, "Standard for Asbestos-Cement Water Pipe." For detailed specifications for the installation of asbestos-cement pipe, reference should be made to AWWA C603, "Standard for the Installation of Asbestos-Cement Pipe." ditions, as well as the internal and ex ternal forces acting on the pipe, be taken into consideration in selecting a class of pipe for any given installation. Finally, sound engineering practice re quires that adequate safety factors be applied to strength requirements to insure performance under less than ideal conditions. Research tests and the application of statistical analysis have shown that asbestos-cement pipe strength may be graphically illustrated by combinedloading parabolic curves. The com bined-loading theory developed by the late W. J. Schlick1 is used in this handbook as the basis for selection curves for asbestos-cement water pipe. External-load determinations for un derground conduit used in this hand book are based on the data in Chapter 9 of the Manual on Design and Con struction of Sanitary and Storm Sewers2 produced jointly by ASCE and WPCF. Sec. 2--Strength and Design Fac tors The strength of asbestos-cement water pipe must be sufficient to with stand the combined forces of internal hydrostatic pressure and external loads. Furthermore, the conditions under which the pipe is installed have a direct relationship to its ability to resist these forces. Therefore, satis'actory pipe performance in field jervice requires that the bedding con Sec. 3--Bedding Conditions The bedding conditions described in Table 1 have been selected as repre sentative of typical installation condi tions encountered in the field. They are illustrated in Fig. A2. Sec. 4--Combined-Loading Theory Tests of asbestos-cement pipe under various combinations of internal pres sure and external load applied in three-edge bearing (see Sec. 5), indi 1 2 AWWA HANDBOOK cate there is a relationship between the combined loads at the point of pipe fracture. This relationship can be represented by a parabolic curve, as shown in Fig. 1. The equation for the load pressure parabolic curve shown in Fig. 1 may be expressed as: w= (1) in which, P is the internal pressure, in pounds per square inch, that will burst the pipe when no external load TABLE 1 . Typical Field Installation Conditions Bedding Condition (class) A Description Gravel or , sand base-- backfill tamped B Same as A, but backfill not tamped C Pipe laid on earth mounds or pipe barrel on flat trench bottom with ex cavated coupling holes --backfill tamped D Same as C, but backfill not tamped Sec. 5--Three-Edge Bearing Load Factors P represents the internal pressure; W the external load. A convenient method of testing pipe for crushing strength (W) is the three-edge-bearing method of loading (Fig. 2). Because the field supporting strength of a conduit is influenced bj the bedding conditions and the lateral pressure acting against the sides of the conduit, it is necessary to apply a load factor to the three-edge-bearing loads in order to correlate them to the field loads. The relationship is expressed as the external load equals load factor times the three-edge-bear ing load. exists; W is the external load, in pounds per lineal foot of pipe, in the three-edge bearing test, that will crush the pipe when no internal pressure exists; p is the internal pressure, in pounds per square inch which, in com bination with some external load (w) applied in three-edge bearing, will fracture the pipe; and w is the exter nal load, in pounds per lineal foot of pipe applied in three-edge bearing which, in combination with some in ternal pressure (p), will fracture the pipe. TABLE 2 Correlation of Bedding Conditions, Pipe Size, and Load Factors Bedding Class A B C D Pipe Size in. 4-12 14-20 24-36 4-36 4-12 14-20 24-36 4-36 Load Factor 1.7 1.8 2.0 1.5 1.3 1.4 1.5 1.1 ASBESTOS-CEMENT PIPE 3 Table 2 shows load factors to be applied for any one of the bedding con ditions described in Table 1. Sec. 6--Hydrostatic Pressures The hydrostatic pressures to be con sidered in pipeline design are static operating pressure and surge pressure. The static pressure will be fixed by the particular field service condition. Ordinary surge pressure conditions are allowed for in this handbook by applying a safety factor of at least 4.0 to internal pressure in combined loading. Where exceptional surge pressures are a necessary specific con sideration in design, a conservative basis for surge allowance determina tion is the method proposed by S. Logan Kerr. Kerr's method considers the funda mental relations affecting water ham mer, including velocity of flow in the pipeline, length of the pipeline, time of valve operation or interruption of flow, and the pressure wave velocity. Water hammer allowance is deter mined by the formulas of Eq 2 and 3 h -- 2.3 p = -- g (2) In Eq 2, h is the water hammer al lowance, in feet; p is the water ham mer allowance, in pounds per square inch; a is the velocity of the pressure wave, in feet per second; g is the ac celeration due to gravity (32.2 fps /sec); and V is the flow line velocity, in feet per second, cut off by the valve operation or other action in the critical time, or less. . 4660 a 4'Hi (3) In Eq 3, a is the pressure wave velocity in feet per second; k is the modulus of compression of water, in pounds per square inch (290,000-300,000 psi); E is the modulus of elasticity of asbestoscement pipe, in pounds per square inch (3,400,000 psi) ; d is the internal di ameter, in inches; and e is the wall thickness, in inches. w W represents load; R, approximately 0.5 in.--the radius of the bearings; D, the nominal diameter of the pipe; and C, the clear space between wooden supports. C should be 0.5 in. for diameters of 12 in. and under, 1 in. for 14-24 in. inclu sive, and 2 in. for 30 in. and over. Sec. 7--External Loads External loads on conduit are of two types: those due to gravity earth loads and those due to superimposed loads, which may be static or moving. The magnitude of gravity earth loads may be computed by using the theory developed by Anson Marston.4 Marston's theory, in general, states that the load on a buried conduit is equal to the weight of a prism of earth (called the interior prism) directly over the conduit, plus or minus the 4 AWWA HANDBOOK TABLE 3 Impact Factors Caused by Moving Vehicles Type of Traffic Highway Railway Airfield runways, taxiways, aprons, or hardstands Impact Factor (F) 1.50 1.75 1.00 1.50 frictional shearing forces transferred to that prism by the adjacent prisms of earth. The magnitude and direc tion of these frictional forces are a function of the amount of relative set tlement occurring between the interior and adjacent earth prisms. The gen eral form of Marston's equation is W = CwB2 in which W is the vertical load, per lineal foot, acting on the con duit because of gravity earth loads; w is the weight of earth, in pounds per cubic foot; B is the trench or conduit width, depending on installation condi tions; and C is a coefficient that in cludes the effect of: (1) the ratio of the height of the fill to the width of the trench or conduit, (2) the shearing forces between the interior and adja cent earth prisms, (3) the direction and amount of relative settlement be tween interior and adjacent earth prisms for embankment conditions, and (4) the rigidity of conduit support for embankment conditions. The selection curves included in this handbook were developed using the load-pressure formula, with the ex ternal load intercept being the crush ing strength as tabulated in Table 2 of AWWA C400-65, "Standard for Asbestos-Cement Water Pipe," and the design point on the parabolic curve being that condition existing at a 5-ft depth of cover with the trench width assumed as pipe ID plus 2 ft, a bedding condition of Class C and a soil weight of 120 lb/cu ft. The external loads were based on the positive projecting conduit analysis because this analysis produced the governing load on the pipe at the conditions set forth above. The design point for each class of pipe is based on a safety factor of 4 times the pressure-pipe class and 2.5 times 0 10 20 30 40 50 60 Coefficient -- Cc Fig. 3. Graph for Determining Load Coefficient Values 70 The graph shows a plot of load coefficient values Cc against values obtained by dividing the height of the fill above the conduit by the outside width of the conduit H/Bc. ASBESTOS-CEMENT PIPE 5 the three-edge bearing equivalent of the trench load. Once the parabolic curve has been established through the external-load intercept and the control point, the equivalent depth of cover scale is correlated for the various bed ding conditions utilizing either the trench load condition or the positive projecting-conduit load condition, whichever is the governing load condition. Values for external loads may be determined by Marston's formula W' = Ccw{Bcy (4) in which Wc is the load on the con duit, in pounds per lineal foot; w is the unit weight of the soil, in pounds per cubic foot; Bc is the outside width of conduit, in feet; and C,, is the load coefficient. (Tables of external loads, based on soil weight of 120 lb/cu ft, are presented in Table Al.) 0.1 0.2 0.3 0.4 0.5 0.6 0.8 1 Coefficient 2 3 45 Fig. i. Graph for Determining Cd Coefficients Each of the above curves represent Cd values for ku and ku'. A represents 0.1924 for granular materials without cohesion; B is 0.165 maximum for sand and gravel; C is 0.150 maximum for saturated top soil; D, 0.13 maximum for ordinary clay; and E, 0.110 maximum for saturated clay. The symbol u', is the coefficient of friction be tween the backfill material and the sides of the ditch. 6 AWWA HANDBOOK In Marston's formula, the load co efficient, Co, is a function of H/Be, P, fid, w, k; H is the height of the fill above the conduit; in feet; p is the projection ratio, that is, the ratio of the distance of the top of the conduit above the natural grade, to the width of the conduit; r,d is the settlement ratio; g. is the coefficient of internal friction of the backfill material; and k is the Rankins ratio of lateral pres sure to vertical pressure. Co = 1.892 =- - 0.96. De (5) Occasionally, a "trench condition" exists in which the width of the trench is less than two or three times the width of the conduit. In such cases, Marston's trench condition formula may be used for determinations of the gravity loads Wd = Caw(Bd)2, in which Wd is the vertical load, in pounds per lineal foot; Bd is the width of the trench; w is the weight of the backfill soil in pounds per cubic foot, Fig. 6. Concentrated Superimposed Load P represents the concentrated load; H, the height from the top of the conduit to the ground surface; Bc, the width of the conduit; and, L, the length of the conduit. Based on a flat-bottomed, backfilltamped trench, conservative values of p = 1.0, rsdp = 0.70, and ku = 0.192 were used in the determination of external loads for the performance curves. C0 values may be determined from Fig. 3, which shows a plot of Co against H/B0 ratios. For values of H/B0 greater than 1.3, when rsdp = 0.70, the graph is linear and values may be determined by the empirical equation Fig. 6. Distributed Superimposed Load D and M are the width and length, in feet, respectively, of the area over which the distributed load acts. The uniform load is lbs per sq ft acting on area D X M. and Cd is a load coefficient. (See Fig. 4 for values of Cd). Where unusually heavy super imposed loads or impact loads are present, the solution of their magni tude may be computed for either a concentrated-load (such as a truck load) or a distributed-load condition. Normal truck and accompanying im pact loads need not be considered when the depth of the cover is greater than 6 ft. The magnitude of superimposed load produced by a concentrated load (see Fig. 5) is determined by use of the formula. ASBESTOS-CEMENT PIPE 7 Wsc -- Cs (6) in which Wsc is the load on the con duit, in pounds per lineal foot; P is the Concentrated load, in pounds; F is the impact factor used to allow for the effects of dynamic loads due to moving vehicles (see Table 3); Cs is a load coefficient, a function of BC/2H and L/2H (see Tables 4 and 5); Be is the width of the conduit, in feet (OD of the pipe) ; H is the height from the top of the conduit to the ground surface, in feet; and L is the effective length of the conduit, in feet. L is 3 ft for conduits greater than 3 ft in length, but is the actual length of conduit for conduits 3 ft long or less. In the case of a distributed super imposed load, the formula may be re written in the form of, Wai = CspFBc (7) in which Wsd is the load on the con duit, in pounds per lineal foot (see TABLE 4 Values of Load Coefficients for Concentrated and Distributed Superimposed Loads Centered Vertically over Conduit D/2H or 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.2 1.5 2.0 ML 2H ! 2H 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.2 1.5 2.0 5.0 0.019 0.037 0.053 0.067 0.037 0.072 0.103 0.131 0.053 0.103 0.149 0.190 0.067 0.131 0.190 0.241 0.079 0.155 0.224 0.284 0.089 0.174 0.252 0.320 0.097 0.189 0.274 0.349 0.103 0.202 0.292 0.373 0.108 0.211 0.306 0.391 0.112 0.219 0.318 0.405 0.117 0.229 0.333 0.425 0.121 0.238 0.345 0.440 0.124 0.244 0.355 0.454 0.128 0.248 0.360 0.460 0.079 0.089 0.097 0.103 0.155 0.174 0.189 0.202 0.224 0.252 0.274 0.292 0.284 0.320 0.349 0.373 0.336 0.379 0.414 0.441 0.379 0.428 0.467 0.499 0.414 0.467 0.511 0.546 0.441 0.499 0.546 0.584 0.463 0.524 0.584 0.615 0.481 0.544 0.597 0.639 0.505 0.572 0.628 0.674 0.525 0.596 0.650 0.703 0.540 0.613 0.674 0.725 0.548 0.624 0.688 0.740 0.108 0.112 0.117 0.121 0.124 0.211 0.219 0.229, 0.238 0.244 0.306 0.318 0.333 0.345 0.355 0.391 0.40$ 0.425 0.440 0.454 0.463 0.481 0.505 0.525 0.540 0.524 0.544 0.572 0.596 0.613 0.574 0.597 0.628 0.650 0.674 0.615 0.639 0.674 0.703 0.725 0.647 0.673 0.711 0.742 0.766 0.673 0.701 0.740 0.774 0.800 0.711 0.740 0.783 0.820 0.849 0.742 0.774 0.820 0.861 0.894 0.766 0.800 0.849 0.894 0.930 0.784 0.816 0.868 0.916 0.956 TABLE 5 Values of Load Coefficients Cs for Concentrated Superimposed Loads Centered Vertically Over Conduit tn. 2 2.5 3 4 ' 5 6 8 10 12 16 20 4 0.105 0.076 0.055 0.033 0.022 0.016 0.009 0.006 0.004 0.002 0.0015 6 0.147 0.106 0.078 0.046 0.031 0.023 0.013 0.008 0.006 0.003 0.002 8 0.191 0.137 0.102 0.061 0.041 0.029 0.017 0.010 0.008 0.004 0.003 10 0.237 0.174 0.129 0.078 0.052 0.037 0.022 0.013 0.009 0.006 0.0035 12 0.279 0.202 0.153 0.092 0.062 0.044 0.025 0.016 0.011 0.007 0.004 14 0.317 0.232 0.175 0.106 0.071 0.050 0.030 0.018 0.013 0.008 0.005 16 0.354 0.259 0.197 0.121 0.081 0.057 0.034 0.021 0.015 0.009 0.0055 18 0.391 0.289 0.221 0.136 0.092 0.066 0.038 0.025 0.017 0.010 0.006 20 0.422 0.316 0.241 0.150 0.102 0.073 0.042 0.027 0.019 0.011 0.007 24 0.478 0.362 0.280 0.177 0.120 0.087 0.050 0.033 0.022 0.013 0.008 30 0.543 0.423 0.332 0.213 0.147 0.106 0.062 0.041 0.029 0.016 0.010 36 0.590 0.470 0.375 0.248 0.171 0.124 0.073 0.049 0.035 0.020 0.012 8 AWWA HANDBOOK Fig. 6); p is the intensity of distri buted load, in pounds per square foot ; F is the impact factor (see Table 3); Bo is the width of conduit, in feet; Cs is a load coefficient, a function of D/2H and M/2H (see Table 4) ; H is the height from the top of the con duit to the ground surface, in feet; and D and M are the width and length, respectively, of the area over which the distributed load acts, in feet. Sec. 8--Safety Factors In developing the selection curves, a safety factor of 4.0 was applied to internal pressures; and a safety factor of 2.5 was applied to external loads. Furthermore, pipe selected from the curves will have a safety factor of at least 2.5 for internal pressure when combined with a safety factor of 2.5 for resisting an external load consisting of the total equivalent earth load plus a 10,000-lb wheel load and impact load. Under impact loading conditions, the 2.5 safety factor for internal pressure represents good design practice, for it is unlikely that internal surge pres sure would occur at the same instant as external impact. change in the safety factor, the equiv; lent external load should be determined and the selection curve entered at the proper value on the design external load scale. The field supporting strength listed for pipe so selected has been proved conservative during many years of performance under various field conditions. . The application of the curves to design is shown in the following problem: Required: A 6-in. pipe to operate at a pressure of 120 psi at 8 ft depth of cover. Bedding condition Class C, soil weight 120 lb/cu ft. Solution: Enter the selection curve for 6-in. pipe at bedding condition Class C, 8 ft cover. The intersection of the 8-ft cover line with the 120 psi operating pressure line falls between pipe Classes 100 and 150. Use 6 in Class 150. , The intersection of the 8 ft cover line with the Class 150 curve is at 135 psi operating pressure, or 550 psi design pressure. Therefore, the pres sure safety factor equals 550/120 = 4.6, with a safety factor of 2.5 for external load. Sec. 9--Selection Curves The selection curves for pipe sizes 4-36 in. are based on combined-loading theory. The curves may be conveniently used by entering them through the depth of cover and bedding condition scales. The scales are correlated to the three-edge bearing equivalents of the design external loads with a safety factor of 2.5. Where there is an ex ternal loading condition different from that due only to depth of cover, how ever, or where conditions warrant a References 1. Schlick, W. J. Supporting Strengths for Cast-Iron Pipe for Water and Gas Service. Iowa State Coll. Eng. Sta. Bull., No. 146 (Jun. 1940). 2. ASCE. Design and Construction of Sanitary and Storm Sewers. Manual of Engineering Practice No. 37. Am. Soc. Civ. Engrs., New York (1960). 3. Kerr, S. L. Practical Aspects of Water Hammer. Jour. AWWA, 40:699 (Jun. 1948). 4. Marston, Anson. The Theory of Ex ternal Loads on Closed Conduits in the Light of Latest Experiments. Iowa State Coll. Eng. Exp. Sta. Bui No. 96 (1930). APPENDIX Data developed for the preparation of the selection curves are included in this appendix. Figures illustrating the various bedding conditions and the earth load conditions used in the preparation of the selection curves are included. In the table of design internal pres sure and design external-load inter cepts, the external loads are the crush ing loads that the pipe must be able to support without failure as specified in AWWA C400--"Standard for Asbestos-Cement Water Pipe." The tables of design external load (a/) for various field bedding conditions and depths of cover show the calculated lads for Class 150 pipe. For Class i00 pipe, similar calculated loads would be less than those shown in the tables, and for Qass 200 pipe, the loads would be greater. The maxi mum variation would be less than 5 per cent. Fig. A2. Bedding Conditions Illustrated Fig. Al. Earth Load Conditions Diagram (a) illustrates trench conduit conditions; that is, the trench width is less than two or three times Bc. Diagram (&) shows a positive projecting conduit condition; that is, the trench width is areater than two or three times Bc. The shaded area represents backfill. Class A bedding conditions are shown in (a) and (b). Class C conditions are shown in (c) and (d). In all four di agrams, the lightly shaded area represents approved backfill, not frozen and free from lumps, large stones, boulders, or other unsuitable substances. The heavily shaded areas represent approved backfill, carefully tamped in 4 in. layers. In (a), a minimum of 2 in. of sand is placed in a shaped bottom under the pipe. In (b), the pipe is bedded in a gravel base. In (c), the pipe barrel rests on earth mounds. In (d), the pipe barrel is rest ing on the flat bottom of the trench. Class B condition is the same as Class A, and Class D is the same as Class C except that the backfill is not tamped in B or D 9 10 AWWA HANDBOOK TABLE A1 Determination of Design External Load (to) Applied in 3-Edge Bearing 1 '2 31 2 31 2 3 Vf to to External External External Pipe Size in. Ex ternal Load lb Equivalent Load Three-Edge Applied in Bearing Load Three-Edge / Col. 1 \ Bearing VLoad Factor,/ (Col. 2X2.5 Ex ternal Load lb Equivalent Load Three-Edge Applied in Bearing Load Three-Edge / Col. 1 \ Bearing \Load Factor/ (Col. 2X2.5 Ex ternal Load lb Equivalent Load Three-Edge Applied in Bearing Load Three-Edge / Col. 1 \ Bearing \Load Factor/ (Col. 2 X 2.5 Factor of Factor of Factor of Safety) Safety) Safety) Class A Bedding Condition 2.5 ft of Cover 4 219 6 297 8 371 10 450 12 507 14 559 16 604 18 643 20 670 24 802 30 887 36 976 129 175 218 264 298 311 335 357 372 401 444 488 323 438 545 660 745 778 838 893 930 1,002 1,110 1,220 12 ft of Cover 4 1,127 6 1,584 8 2,051 10 2,451 12 2,678 14 2,886 16 3,130 18 3,337 20 3,551 24 4,032 30 4,666 36 5,400 663 932 1,206 1,441 1,575 1,603 1,738 1,853 1,972 2,016 2,333 2,700 1,658 2,330 3,015 3,603 3,938 4,008 4,345 4,633 4,930 5,040 5,833 6,750 5 ft of Cover 458 634 814 1,012 1,174 1,336 1,484 1,644 1,779 2,022 2,328 2,552 269 373 479 595 691 742 825 914 988 1,011 1,164 1,276 673 933 1,198 1,488 1,728 1,855 2,063 2,285 2,470 2,528 2,910 3,190 16 ft of Cover 1,510 2,124 2,602 2,835 3,078 3,367 3,663 3,969 4,277 4,800 5,589 6,450 888 1,249 1,531 1,668 1,811 1,870 2,035 2,205 2,376 2,400 2,794 3,225 2,220 3,123 3,828 4,170 4,528 4,675 5,088 5,513 5,940 6,000 6,985 8,063 8 ft of Cover 744 1,041 1,344 1,688 1,975 2,267 2,398 2,528 2,712 3,014 3,451 3,990 438 612 790 993 1,162 1,259 1,332 1,404 1,506 1,507 1,725 1,995 1,095 1,530 1,975 2,483 2,905 3,148 3,330 3,510 3,765 3,768 4,313 4,988 20 ft of Cover 1,893 2,550 2,816 3,076 3,402 3,727 4,063 4,336 4,680 5,376 6,318 7,500 1,113 1,500 1,656 1,809 2,001 2,070 2,257 2,409 2,600 2,688 3,159 3,750 2,783 3,750 4,140 4,523 5,003 5,175 5,643 6,023 6,500 6,720 7,898 9,375 Class B Bedding Condition 2.5 ft of Cover 5 ft of Cover 8 ft of Cover . 4 219 6 297 8 371 10 450 12 507 14 559 16 604 18 643 20 670 24 734 30 887 36 976 146 198 248 300 338 373 402 428 447 489 592 651 365 458 495 634 620 814 750 1,012 845 1,174 933 1,336 1,005 1,484 1,070 1,644 1,118 1,779 1,223 2,022 1,480 2,328 1,628 . 2,552 305 423 542 674 783 890 989 1,096 1,186 1,348 1,552 1,701 763 1,058 1,355 1,685 1,958 2,225 2,473 2,740 2,965 3,370 3,880 4,253 744 1,041 1,344 1,688 1,975 2,267 2,398 2,528 2,712 3,014 3,451 3,990 496 694 896 1,126 1,317 1,512 1,598 1,685 1,808 2,009 2,300 2,660 1,240 1,735 2,240 2,815 3,293 3,780 3,995 4,213 4,520 5,023 5,750 6,650 ASBESTOS-CEMENT PIPE 11 TABLE A1--Determination of Design External Load (w) Applied in 3-Edge Bearing (contd.) 12 31 2 3l 2 3 V) to to External External External Pipe Size in. Ex ternal Load lb Equivalent Three-Edge Load Applied in Bearing Load Three-Edge / Col. 1 \ Bearing \Load Factor/ (Col. 2 X 2.5 Ex ternal Load lb Equivalent Three-Edge Load Applied in Bearing Load Three-Edge / Col. 1 \ Bearing \Load Factor/ (Col. 2 X 2.5 Ex ternal Load lb Equivalent Load Three-Edge Applied in Bearing Load Three-Edge / Col. 1 \ Bearing \Load Factor/ (Col. 2 X 2.5 Factor of Factor of Factor of Safety) Safety) Safety) Class B Bedding Condition {contd.) 12 ft of Cover 4 1,127 6 1,584 8 2,051 10 2,451 12 2,678 14 2,886 16 3,130 18 3,337 20 3,551 24 4,032 30 4,666 36 5,400 751 1,056 1,367 1,634 1,785 1,924 2,086 2,224 2,367 2,688 3,110 3,600 i 1, j 1,878 2,640 3,418 4,085 4,463 4,810 5,215 5,560 5,918 6,720 7,775 9,000 16 ft of Cover 1,510 2,124 2,602 2,835 3,078 3,367 3,663 3,969 4,277 4,800 5,589 6,450 1,007 1,416 1,735 1,890 2,052 2,244 2,442 2,646 2,851 3,200 3,726 4,300 i 2,518 3,540 4,338 4,725 5,130 5,610 6,105 6,615 7,128 8,000 9,315 10,750 20 ft of Cover 1,827 2,550 2,816 3,076 3,402 3,727 4,063 4,336 4,680 5,376 6,318 7,500 1,218 1,700 1,877 2,050 2,268 2,485 2,708 2,891 3,120 3,584 4,212 5,000 3,045 4,250 4,693 5,125 5,670 6,213 6,770 7,228 7,800 8,960 10,530 12,500 Class C Bedding Condition 2.5 ft of Cover 4 219 6 297 8 371 10 450 12 507 14 559 16 604 18 643 20 670 24 734 30 887 36 976 168 228 286 346 390 400 431 459 479 489 592 651 420 570 715 865 975 1,000 1,078 1,148 1,198 1,223 1,480 1,628 12 ft of Cover 4 1,127 6 1,584 8 2,051 10 2,451 12 2,678 14 2,886 16 3,130 18 3,337 20 3,551 24 4,032 30 4,666 36 , 5,400 867 1,219 1,578 1,885 2,060 2,061 2,235 2,383 2,536 2,688 3,110 3,600 2,168 3,048 3,945 4,713 5,150 5,153 5,588 5,958 6,340 6,720 7,775 9,000 5 ft of Cover 458 634 814 1,012 1,174 1,336 1,484 1,644 1,779 2,022 2,328 2,552 352 488 626 778 903 954 1,060 1,175 1,270 1,348 1,552 1,701 880 1,220 1,565 1,945 2,258 2,385 2,650 2,938 3,175 3,370 3,880 4,253 16 ft of Cover 1,510 2,124 2,602 2,835 3,078 3,367 3,663 3,969 4,277 4,800 5,589 6,450 1,161 1,634 2,002 2,181 2,368 2,405 2,616 2,835 3,055 3,200 3,726 4,300 2,903 4,085 5,005 5,453 5,920 6,013 6,540 7,088 7,638 8,000 9,315 10,750 8 ft of Cover 744 1,041 1,344 1,688 1,975 2,267 2,398 2,528 2,712 3,014 3,451 3,990 573 801 1,034 1,299 1,519 1,619 1,712 1,805 1,937 2,009 2,300 2,660 1,433 2,003 2,585 3,248 3,798 4,048 4,280 4,513 4,843 5,023 5,750 6,650 20 ft of Cover 1,893 2,550 2,816 3,076 3,402 3,727 4,063 4,336 4,680 5,376 6,318 7,500 1,456 1,961 2,166 2,366 2,617 2,662 2,902 3,097 3,343 3,584 4,212 5,000 3,640 4,903 5,415 5,915 6,543 6,655 7,255 7,743 8,358 8,960 10,530 12,500 12 AWWA HANDBOOK TABLE A1--Determination of Design External Load (w) Applied in 3-Edge Bearing (contd.) 12 3 1 2, 3 1 2 3 10 t0 iff Pipe Size in. Ex ternal Load lb Equivalent Three-Edge Bearing Load / Col. 1 \ External Load Applied in Three-Edge Bearing \Load Factor/ (Col. 2 X 2.5 Ex ternal Load lb Equivalent Three-Edge Bearing Load / Col. 1 \ External Load Applied in Three-Edge Bearing \Load Factor/ (Col. 2 X 2.5 Ex ternal Load lb Equivalent External Load . Three-Edge Applied in Bearing Load Three-Edge / Col. 1 \ Bearing \Load Factor/ (Col. 2 X 2.5 Factor of Factor of Factor of Safety) Safety) Safety) Class D Bedding Condition 2.5 ft of Cover 5 ft of Cover 8 ft of Cover 4 219 6 297 8 371 10 450 12 507 14 559 16 604 18 643 20 670 24 734 30 887 36 976 199 270 338 409 461 509 549 584 610 667 807 887 498 675 845 1,023 1,153 1,273 1,373 1,460 1,525 1,668 2,018 2,218 458 634 814 1,012 1,174 1,336 1,484 1,644 1,779 2,022 2,328 2,552 416 577 740 920 1,068 1,214 1,349 1,495 1,617 1,838 2,116 2,320 1,040 1,443 1,850 2,300 2,670 3,035 3,373 3,738 4,043 4,595 5,290 5,800 744 1,041 1,344 1,688 1,975 2,267 2,398 2,528 2,712 3,014 3,451 3,990 677 946 1,221 1,535 1,795 2,061 2,180 2,298 2,465 2,740 3,137 3,627 1,693 2,365 3,053 3,838 4,488 5,153 5,450 5,745 6,163 6,850 7,843 9,068 12 ft of Cover 16 ft of Cover 20 ft of Cover 4 1,127 6 1,584 8 2,051 10 2,451 12 2,678 14 2,886 16 3,130 18 3,337 20 3,551 24 4,032 30 4,666 36 5,400 1,025 1,440 1,864 2,228 2,434 2,623 2,845 3,033 3,228 3,665 4,241 4,909 2,563 3,600 4,660 5,570 6,085 6 558 7,113 7,583 8,070 9,163 10,603 12,273 1,510 2,124 2,602 2,835 3,078 3,367 3,663 3,969 4,277 4,800 5,589 6,450 1,373 1,931 2,366 2,578 2,798 3,061 3,330 3,608 3,888 4,364 5,081 5,864 3,433 ' 4,828 5,915 6,445 6,995 7,653 8,325 9,020 9,720 10,910 12,703 14,660 1,893 2,550 2,816 3,076 3,402 3,727 4,063 4,336 4,680 5,376 6,318 7,500 1,721 2,318 2,560 2,796 3,093 3,388 3,693 3,942 4,255 4,887 5,744 6,818 4,303 5,795 6,400 6,990 7,733 8,470 9,233 9,855 10,638 12,218 14,360 17,045 ASBESTOS-CEMENT PIPE Design External Load --ib/lin ft 13 Design Pressure-psi Operating Pressure psi- Bedding Conditions Depth of Cover-ft Pig. A3. Selection Curves for 4-in. Asbestos-Cement Pipe 14 0 1,000 AWWA HANDBOOK Design External Load-lb/lin ft 2,000 3,000 4,000 5,000 ' 6,000 Design Pressure--psi Operating Pressure psi- Bedding Conditions Fig. A4. Selection Curves for 6-in. Asbestos-Cement Pipe ASBESTOS-CEMENT PIPE Design External Load-lb/lin ft 15 Design Pressure-psi Operating Pressure--psi Bedding Conditions Depth of Cover-ft Fig. A5. Selection Curves for 8-in. Asbestos-Cement Pipe Design Pressure --psi Operating P ressure-psi 16 AWWA HANDBOOK Design External Load -- Ib/Jin ft Depth of Cover-ft Pig. A6. Selection Curves for 10-in. Asbestos-Cement Pipe Bedding Conditions ASBESTOS-CEMENT PIPE 17 Design P ressure-psi Operating Pressure psi- Bedding Conditions Depth of Cover-ft Fig. A7. Selection Curves for 12-in. Asbestos-Cement Pipe 18 AWWA HANDBOOK 2,000 Design External Load-lb/lin ft 4,000 8,000 1,000 800 600 400 200 Design Pressure-psi Operating Pressure psi- Bedding Conditions Fig. A8. Selection Curves for 14-in. Asbestos-Cement Pipe ASBESTOS-CEMENT PIPE 19 Design Pressure psi- Operating Pressure psi- Bedding Conditions Depth of Cover-ft Fig. A9. Selection Curves for 16-in. Asbestos-Cement Pipe Design Pressure-psi Operating Pressure psi- 20 AWWA HANDBOOK Design External Load-lb/lin ft Depth of Cover--ft Fig. A10. Selection Curves for 18-in. Asbestos-Cement Pipe Bedding Conditions ASBESTOS-CEMENT PIPE Design External Load -- lb/!in ft 21 Design P ressure-psi Operating Pressure psi- Bedding Conditions . Depth of Cover-ft Fig. All. Selection Curves for 20-in. Asbestos-Cement Pipe Design Pressure-psi Operating Pressure psi- 22 AWWA HANDBOOK Design External Load--Ib/lin ft Depth of Cover-ft Fig. A12. Selection Curves for 24-in. Asbestos-Cement Pipe Bedding Conditions ASBESTOS-CEMENT PIPE . Design External Load --Ib/lin ft 23 Design Pressure -p s i Operating Pressure psi- Bedding Conditions Depth of Cover-ft I Tig. A13. Selection Curves for 30-in. Asbestos-Cement Pipe Design P ressure-psi Operating Pressure psi- 24 AWWA HANDBOOK Depth of Cover-ft Fig. A14. Selection Curves for 36-ln. Asbestos-Cement Pipe Bedding Conditions ASBESTOS-CEMENT PIPE 25 TABLE A2 Design Internal Pressure and Design External Load Intercepts for Use With Selection Curves in. \ 4 6 8 10 12 14. 16 18 20 24 30 36 Class 100 P psi ' 417 441 472 490 490 SOO 500 495 493 479 468 465 w lb/tin ft 4,100 4,000 4,000 4,400 5,200 5,200 5,800 6,500 7,100 8,100 9,700 11,200 Class 150 Pw psi Ib/lin ft 616 5,400 632 5,400 653 5,500 650 7,000 658 7,600 650 8,600 654 9,200 655 10,100 656 10,900 645 12,700 638 15,900 630 19,600 Class 200 PW psi Ib/lin ft 809 8,700 815 9,000 824 9,300 826 11,000 830 11,800 826 13,500 825 15,400 826 17,400 824 19,400 820 22,600 816 28,400 813 33,800 5P--3M--12/73--43401