Civil Engineering Reference
In-Depth Information
Fig. 1.42 Relative cross-
section of the fibre core for
ropes with strand lay angle
b = 20, Jenner (
1992
)
0.3
8 strand
z
w
= 6
z
w
= 14
z
w
=
∞
0.2
z
w
= 6
z
w
= 14
z
w
=
∞
6 strand
0.1
0
0.2
0.1
rel. strand clearance s
s
/d
s
1.6.4 Steel Core
Unlike in wire ropes with fibre cores, wire ropes with steel cores especially with
the usual independent wire rope core (IWRC) and the wire strand core (WSC)
should not have high clearance between the strands.
When dimensioning the independent wire rope core, it has to be considered that
the wires of the core and the strands comb each other in a complicated way. Jenner
(
1992
) found the results given by a geometrically based calculation with the nec-
essary assumptions are no better than those from a regression calculation using rope
measurements. The regression equation for the ropes with different steel cores is
Table 1.14
Variables and constants for the calculation of the actual rope diameter, Jenner (
1992
)
Core
IWRC
WSC
PWRC
ESWRC
Under the specific
tensile force S/d
2
d
m
d
cal
d
m
d
cal
d
m
d
cal
d
m
d
S2
y
s
S2
d
S2
s
S1
d
S1
s
S2
d
S2
s
S2
S2
x
1
A
d
S2
x
2
d
2
d
1
d
1
d
0
d
2
d
1
a
0
0.9924
0.7855
1.026
3.2146
S/d
2
= 0
a
1
-0.1206
0.1587
-0.2375
-0.2216
a
2
-0.0156 0.2095 -0.0226 0.0921
a
0
0.9759 0.8748 1.0069 2.5867
a
1
-0.1555 -0.1116 -0.0392 -0.1354 S/d
2
= 117
a
2
-0.0117 0.1115 -0.0210 0.1781 N/mm
2
Symbols d
m
actual rope diameter; d
cal
rope diameter calculated with incompressible round
strands; d
S1
,d
S2
diameter of the strands 1, 2; A metallic cross-section of the wire rope
d
0
, d
1
, d
2
outer wire diameter of the strands 0, 1 and 2
s
S1
,s
S2
clearance between the strands 1 and 2
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