COLD REGIONS TECHNICAL DIGEST NO. 96-1
16
where p is the uniform load on the boom per unit width of river
(= fb as computed above in eq 1) and θ is the angle between the
chord and the line perpendicular to the direction of force.
The complete geometry of the boom cable may be approximated
by:
x
y = x tan θ + 4s 1 -
(10)
L
Choice of wire rope
Several considerations affect the choice of a wire rope. First,
and most important, published wire rope strengths are considered
to be breaking, and not working strength, so a factor of safety is
needed. Table 3 lists the load carrying capacity of common sizes
and types of galvanized wire rope. Second, standard hoisting rope
(6 19 construction)* is recommended for booms because of its
high strength, good wearing characteristics, and availability. Third,
* 6 19 means that the rope is composed of six strands, and each strand is made
up of 19 wires.
Table 3. Nominal strength of 6 19 galvanized improved plow steel
wire rope.
Nominal strength (tons)*
of 2,000 pounds
6 19 galvanized
Approximate weight
Diameter
Diameter
improved plow steel
per foot (lb)**
IWRC†
(in.)
(mm)
Fiber core
Fiber core
IWRC
1/4
6.3
2.47
2.65
0.105
0.116
5/16
7.9
3.83
4.12
0.164
0.180
3/8
9.5
5.49
5.90
0.236
0.260
7/16
11.1
7.44
8.00
0.32
0.35
1/2
12.7
9.63
10.30
0.42
0.46
9/16
14.3
12.10
13.00
0.53
0.59
5/8
15.9
15.00
16.10
0.66
0.72
3/4
19.0
21.40
23.00
0.95
1.04
7/8
22.2
29.00
31.10
1.29
1.42
1
25.4
37.60
40.40
1.68
1.85
1-1/8
28.6
47.30
50.90
2.13
2.34
1-1/4
31.7
58.10
62.50
2.63
2.89
1-3/8
34.9
69.90
75.10
3.18
3.50
1-1/2
38.1
82.80
89.00
3.78
4.16
1-5/8
41.3
96.30
103.00
4.44
4.88
1-3/4
44.4
112.00
120.00
5.15
5.67
2
50.8
144.00
155.00
6.72
7.39
This type of information can be found in many engineering handbooks or suppliers
catalogs. The above is taken from Washington Chain and Supply, Inc., 2901 Utah
Ave. South, Seattle, Washington 98124.
* 1 ton of 2000 lb = 1.102 metric tonnes
** 1 lbmass = 0.4534 kg
† IWRC = independent wire rope core
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