Civil Engineering Reference
In-Depth Information
Table 1.13 Factor q for the
wire gusset area, Jenner
( 1992 )
Number of outer strand wires
Factor q
Number of strands
z W
Z S = 6
Z S = 8
6
0.222
0.333
9
0.153
0.230
12
0.118
0.177
14
0.102
0.154
According to Jenner ( 1992 ), for round strands with unstructured surface (number
of outer strand wires z W = ?), with the actual rope diameter d m , the strand
diameter d S , the number of strands z S and the strand lay angle b, the cross-section
for the fibre core without the wire gussets is
2
4
3
5
2
d m d S
2
d S
sin p
z S
cos p
z S
cos b
cos 2 b þ tan 2 p
z S
A g ¼ z S
4 cos b arcsin
r
:
ð 1 : 15 Þ
The area of the wire gussets is
DA ¼ q d S
cos b :
ð 1 : 16 Þ
The factor q for 80 % of the real area of the wire gussets and the usual number of
outer strand wires is listed in Table 1.13 and this is valid for layer angles of the
outer strand wires a = 12-18. For more information see Jenner ( 1992 ).
The clearance between the strands in the cross-section can be expressed pre-
cisely enough in a simple form according to Shitkow ( 1957 )as
Þ sin p
z S
d S
s SQ ¼ d m d S
ð
r
cos 2 b þ tan 2 p
z S
ð 1 : 17 Þ
cos p
z S
and the real clearance between the strands is
s S ¼ s SQ cos b :
ð 1 : 18 Þ
The relation between the cross-section of the fibre core in a rope with the actual
diameter A F = d m and the clearance between the strands s S /d S has been calculated
with the equations given earlier and drawn in Fig. 1.42 . This figure is valid for
strand lay angle b = 20 and the usual wire lay angles a.
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