XCMG QAY220, Operation Manual, Page: 21 / 172

QAY220 All Terrain Crane Operation Manual
1-9
When the crane is supported, the outriggers exert considerable pressure F onto the ground. In
certain cases, individual outrigger must take up the weight of the crane as well as the weight of the
load and this is transferred to the ground. The ground must always be able to stand up to the pressure
exerted upon it. If the surface area of the support pads is not sufficient, these must be fixed with a
foundation corresponding to the load-bearing capacity of the ground. The necessary supporting surface
can be calculated from the load-bearing capacity of the ground and the supporting pressure of the crane,
S=F/P.
No. Type of soil
Non-cohesive, sufficiently firm soil:
Cohesive soil:
kg/cm
2
Table 1-2
Fine to medium sand
Coarse sand to gravel
Loamy
Soft
Stiff
Semi solid
Hard
In densely packed strata
Solid or column formation
Artificially compacted ground
1
A
B
A
B
C
D
E
A
B
1
）
2
）
3
）
4
）
1
）
2
）
3
）
2
3
If there is any doubt as to the load-bearing capacity of the ground at the operating site, the ground
must be investigated.
Not artificially compacted
Natural soil, apparently undisturbed
Sludge, peat, marshy earth
Rock with a minimum of fissures, in healthy, un-weathered condition and favourably situated:
Asphalt
Common concrete (concrete group B
Ⅰ
)
High strength concrete (concrete group B
Ⅱ
)
0
～
1
0
1.5
2
0
0.4
1
2
4
15
30
5
～
15
50
～
250
350
～
550
1-9-2 Permissible ground-bearing load
General safe operating practices
Chapter 1
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