One method of restraining a pipeline is to provide a welded-on thrust collar or other dependable anchorage means on one or both sides of the point requiring restraint and to use concrete poured around the collar for support against undisturbed soil surrounding the pipe.
At a bend, the fitting and pipe ends would have to be of a restrained type, adequate to withstand total thrust involved. The required number of thrust collars would be dependent on the magnitude of the thrust force to be restrained and the allowable load per collar.
Thrust collars are also used in lieu of water stops on fabricated wall pipe for installation in load-bearing walls to resist thrust caused by internal pressure.
Size | T 1 | C | Weight | Allowable |
|---|---|---|---|---|
4 | 0.25 | 6.80 | 1 | 4500 |
6 | 0.25 | 8.90 | 2 | 9300 |
8 | 0.25 | 11.05 | 2 | 16000 |
10 | 0.25 | 13.10 | 3 | 24000 |
12 | 0.25 | 15.20 | 3 | 34000 |
14 | 0.25 | 17.30 | 5 | 46000 |
16 | 0.25 | 19.40 | 6 | 59000 |
18 | 0.38 | 22.50 | 15 | 75000 |
20 | 0.38 | 24.60 | 11 | 92000 |
24 | 0.38 | 28.80 | 13 | 130000 |
30 | 0.50 | 36.00 | 29 | 200000 |
36 | 0.50 | 42.30 | 35 | 290000 |
42 | 0.75 | 50.75 | 98 | 390000 |
48 | 0.75 | 57.05 | 111 | 510000 |
54 | 1.00 | 66.06 | 231 | 650000 |
60 | 1.00 | 70.11 | 246 | 745000 |
64 | 1.00 | 74.17 | 261 | 847000 |
1.) These values are based on dead-end thrust due to 250 psi internal pressure. For higher allowable loads or pressures, contact AMERICAN. (See also the figure above Table No. 9–11, for use of thrust collars, e.g., in some buried systems where other types of concrete thrust blocks cannot be used.)
Welded-on thrust collars are normally fabricated from steel. If collars are to be furnished of annealed ductile iron, dimensions and weights are the same as those found in Wall Collar Weights.
Collars may be angled and/or rotated from top dead center (TDC).
