Manitowoc Grove RT765E-2 Operator's Manual page 32

SAFETY INFORMATION
Table 2-4 Example-Capacity Reduction Factors for Wind Speed V(z) Greater than 13.4 m/s - Metric
(Only for lifting with main boom on fully extended outriggers, with or without stowed extension)
For wind speed V(z) (3-second gust speed at boom tip height) V(z) > 13.4 m/s ≤ 20.1 m/s, the Reduced Capacity
shall be calculated by multiplying the Published Rated Capacity by the following factors:
Wind Speed
V(z) > 13.4 m/s
< 20.1 m/s
Factor
Wind resistance area of load, Awr
Maximum allowable wind resistance area, [
Wind resistance area of load, Awr
For wind resistance Area of load, Awr
Operator Manual.
Table 2-5 Awr Ratio and Permissible Wind Speed V(z) - Metric
Note: Permissible and rated wind speeds in this table are the 3-second gust wind speeds at boom tip height.
Ratio:
For Rated Capacity at 13.4 m/s
For Allowable Capacity at 20.1 m/s
Example and Sample Calculations (metric)
The following example illustrates how to calculate allowable
load while operating in wind speed (3-second wind gust
speed) above 13.4 m/s (30 mph) and maximum permissible
wind speeds with various combinations of lifted load and
wind resistance area.
NOTE: Permissible and calculated wind speeds in this
example are the 3-second wind gust speeds at
boom tip height V(z).
Example 1: Crane Configuration:
• boom length = 27.4 m,
• load radius = 9 m,
• wind speed is measured at V(z) ≤ 20.1 m/s.
F r o m t h e R a t e d L o a d C h a r t E x a m p l e - M e t r i c
(Figure 2-3), at maximum permissible wind speed, V(z) =
13.4 m/s, the rated lifting capac ity m
configuration is 15,050 kg.
2-14
10.9 12.2 15.2 18.4
0.9 0.9 0.8
shall not exceed maximum allowable wind resistance area Awr
(load)
2
m ] Awr
= projected wind area Ap x wind drag coefficient Cd for the load.
(load)
> maximum allowable wind resistance area, Awr
(load)
1.2
12.2
18.3
for this
( a l l o w )
Published 4-09-2021, Control # 364-11
Main Boom Length in Meters
21.3 24.4
0.8 0.8 0.8
= 0.0012 x calculated reduced capacity in kg.
(allow)
1.4 1.6
Maximum Permissible Wind Speed (m/s)
11.4 10.6
17.0 15.9
The maximum allowable wind resistance area of load is:
Awr = 0.0012 x m
(allow)
Awr = 0.0012 x 15,050 = 18.06 m
(allow)
Lifting Limits at wind speed V(z) ≤ 13.4 m/s at this
configuration:
• Maximum load 15,050 kg
• Maximum wind resistance area of load 18.06 m
For the allowable wind speed > 13.4 m/s and ≤ 20.1 m/s,
reduce the allowable load. Per Table 2-4, the Factor for main
boom length of 27.4 m is 0.8, the allowable load is:
m = 0.8 x 15,050 = 12,040 kg
(allow)
This reduced capacity load has an allowable wind resistance
area of:
Awr
(allow)
Lifting Limits at wind speed V(z) > 13.4 m/s and
≤ 20.1 m/s, at this configuration:
• Maximum load 12,040 kg
• Maximum wind resistance area of load 14.45 m
RT765E-2 OPERATOR MANUAL
27.4 30.5
0.8 0.7
refer to crane
(allow)
1.8
10.0
15.0
(load)
= 0.0012 x 12,040 = 14.45 m
33.5
0.6
(allow).
2
9.5
14.2
(2.4)
2
2
2
2