The transverse joint must be designed empirically as the stresses in it are indeterminate. The common form of joint for pipes less than 48 inches in diameter is a single-riveted lap joint, and for larger pipes or for pipes exposed to unusual stresses, a double riveted lap joint is used. The same size rivets are used as in the longitudinal joint. The maximum permissible distance between rivets should be used in the transverse joint.
| TABLE 41 | |||||
|---|---|---|---|---|---|
| Properties of Riveted Joints | |||||
| (Chicago Bridge and Iron Works) | |||||
| Type of Joint | Thickness Plate, Inch | Diameter of Rivet, Inch | Pitch, Inches | Efficiency of Joint, Per Cent | Thickness Butt Plate, Inches |
| Single-riveted lap | ¼ | ⅝ | 1.88 | 49 | |
| ¼ | ¾ | 2.25 | 50 | ||
| 5 16 | ⅞ | 2.63 | 50 | ||
| Double riveted lap | ¼ | ⅝ | 2.50 | 70 | |
| 5 16 | ¾ | 3.00 | 71 | ||
| ⅜ | ⅞ | 3.40 | 71 | ||
| Triple riveted lap | ¼ | ½ | 2.39 | 74 | |
| 5 16 | ⅝ | 2.96 | 74 | ||
| ⅜ | ¾ | 3.53 | 75 | ||
| 7 16 | ⅞ | 4.09 | 76 | ||
| Quadruple riveted lap | ⅜ | ⅝ | 3.20 | 77 | |
| 7 16 | ¾ | 3.90 | 78 | ||
| Double riveted butt | ½ | ⅞ | 3.62 | 72 | ⅜ |
| 9 16 | ⅞ | 3.62 | 72 | ⅜ | |
| ⅝ | ⅞ | 3.62 | 72 | ⅜ | |
| 11 16 | ⅞ | 3.62 | 72 | 7 16 | |
| ¾ | 1 | 4.12 | 73 | 7 16 | |
| ⅞ | 1 | 3.82 | 71 | ½ | |
| 1 | 1 | 3.48 | 68 | 9 16 | |
| Triple riveted butt | ⅝ | ⅞ | 4.94 | 80 | ½ |
| ¾ | 1 | 5.62 | 80 | 9 16 | |
| ⅞ | 1 | 5.16 | 78 | 9 16 | |
| 1 | 1 | 4.66 | 76 | 9 16 | |
| Quadruple riveted butt | ¾ | 1 | 7.13 | 84 | ¾ |
| ⅞ | 1 | 6.51 | 83 | 11 16 | |
| 1 | 1 | 5.84 | 81 | ⅝ | |
Pipes used as compression members of a bridge are stiffened by riveting standard rolled steel sections longitudinally on the pipe.
Fig. 78.—Lock Bar Pipe.
Lock Bar Pipe is a steel pipe with a special form of joint made by the East Jersey Pipe Corporation. It is arranged as shown in Fig. 78 and has the advantage of developing the full strength of the plate. It is equivalent to a joint with 100 per cent efficiency, which permits the use of thinner plates.
101. Design of Wood Stave Pipe.—In the design of wood stave pipe[[66]] the entire bursting pressure is taken up by steel bands wrapped around the outside of wood staves which make up the shell of the pipe. The pipe is not designed to resist external loads except those which may be overcome by the internal pressure in the pipe. The thickness of the staves is fixed by experience. The sizes of staves and bands recommended by J. F. Partridge[[67]] are given in Table 40. The size of the steel bands can be determined from the expression;
S = Cr(R + t)
in which S = the total stress in the band; R = the radius of the inside of the pipe; t = the thickness of the stave; r = the area of bearing per unit length of the band on the wood. For circular bands it is assumed as the radius of the band; C = the crushing strength of wood, usually taken at 650 pounds per sq. in.
The preceding expression can be derived easily by the application of the laws of mechanics, and from it the expression for the distance between bands follows logically. It is,