Civil Engineering Reference
In-Depth Information
Table 3.6
Approximate minimum hammer sizes for driving bearing piles based on design load of pile
for drop hammers and single-acting hammers (BSP data)
Design load of pile (kN)
Approximate minimum hammer mass
Steel piles (tonne)
Concrete piles (tonne)
400
−
2
600
2
3
800
1
to 900
2
3
4
1500
5
−
2250
8
−
3000
10
−
1
Concrete pile.
2
Steel pile.
Table 3.7
Typical characteristics of selected BSP hydraulic hammers
Hammer Designation
Impact Energy
Length
Weight
(kNm)
(m)
(kg)
CX 40
40
4.022
5200
CX 50
51
4.022
6100
CX 60
60
4.975
7600
CX 75
71
4.975
8700
CX 85
83
4.975
9800
CX 110
106
5.475
12050
CG 180
180
7.00
17240
CG 210
210
7.45
20430
CG 240
240
7.75
22760
CG 270
270
8.05
25110
CG 300
300
8.35
27460
Note
CX range operates at 36 to 100 blows/minute. Generally suitable for steel sheet piles in pairs, tubular steel-bearing
piles, steel 'H' piles inc. combination piles, reinforced concrete piles, cast-in-place piles and timber piles.
CG range operates at 29 to 100 blows/minute. Generally suitable for tubular steel-bearing piles, steel 'H' piles,
reinforced concrete piles, cast-in-place piles and timber piles.
the more rapid action can make up for this loss in efficiency. The action of a single
acting diesel hammer (e.g. Delmag, Mitsubishi, Vulcan or Kobelco type) is best suited
to driving piles which derive the greater part of their resistance at the pile tip, such as
occurs when driving through granular deposits. The diesel hammer is more versatile
than the drop hammer and for driving vertical piles it can be set on the top of a pile
without guide rails (leaders) attached to the rig. This does not apply to the driving of
raking piles where the pile and hammer still require to be supported. A summary of
selected Delmag hammer specifications is given in Table 3.8.
Using pile-driving analyzers, it has been found that unless very carefully maintained,
the energy delivered by a diesel hammer starting in good condition rapidly diminishes
