Enerpac JS125 - Page 47

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Document number: ED.03783.00.001.ENG rev 4 Page 47 of 153
4.2.3.1 Calculation of GBP skid track
Example of calculating ground bearing pressure
Data
depending
on the
operation
force on one unit
F
unit
1250
kN
number of applied barrels
Nr_barrels
20
side_load
p
3
%
swivel_height
Swivel
height
6000
mm
Fixed data
own mass
one unit
Unit
mass
22
kN
one barrel
Barrel
mass
1
top barrel
Top_barrel
mass
6
measures of the bearing area
Footprint bearing area
0.08
m
2
safety factor s
S
1.65
reaction-width of the trolley
Reaction_width Trolley
914
mm
1. The force on one area caused by the load and the side load is:
F
load and side load
= F
unit
(
1
/
4
+
1
/
2
p * Swivel
height
/ Reaction_width Trolley)
F
load and side load
= 1250 (
1
/
4
+
1
/
2
* 0.03 * 6000 / 914) = 436 kN
2. The force on one area caused by the own mass of the system:
F
own mass
= (Unit
mass
+ Top_barrel
mass
+ Nr_barrels * Barrel
mass
) / 4
F
own mass
= (22 + 6 + 20 * 1) / 4 = 12 kN
3. Total total force on one area is
F
total
= F
load and side load
+ F
own mass
F
total
= 436 + 12= 448kN
4. Take the safety factor into account:
F
total safe
= F
total
* S
F
total safe
=448 * 1.65 = 739 kN
5. Dimensions of the skid tracks.
The dimensions of the bearing surface are as follows:
Parameter
Abbrev
Value
Skid track
height
Skid height
0.2 [m]
width
Skid width
0.2 [m]