Piling equipment and methods 89and the resulting explosion imparts an additional ‘kick’to the pile, which is already moving
downwards under the blow of the ram. Thus the blow is sustained and imparts energy over
a longer period than the simple blow of a drop or single-acting hammer. The ram rebounds
after the explosion and scavenges the burnt gases from the cylinder. The well-known
Delmag series of hammers (Figure 3.15) ranges from the D6 with a ram mass of 600 kg for
driving piles up to 2000 kg to the 20 tonne ram of the D200 with a drop height of 3.4 m for
piles up to 250 tonne. ICE and MKT manufacture double-acting diesel hammers with a
striking rate of 70 to 90 blows per minute compared with the rates of 40 to 60 blows per
minute attained by the comparable makes of single-acting diesel hammers. The characteristics
of various makes of diesel hammer are shown in Table 3.4.
Table 3.3Characteristics of some double-acting and differential-acting piling hammers
Maker Type Mass of ram Maximum Maximum
(kg) energy per blow striking rate
(kJ) (blows/min)
BSP International 600Na 227 4 250
Foundations Limited (UK) 700Na 385 7 225
SL20da 1500 20 84
SL30da 2500 30 84
Dawson Construction HPH1200 1040 12 80 – 120
Plant (UK) HPH1800 1500 19 80 – 120
HPH2400 1900 24 80 – 120
HPH4500 3500 45 80 – 120
HPH6500 4650 65 80 – 120
HPH10K 6500 100 80 – 120
MKTa (USA) 9B3 725 12 145
10B3 1360 18 105
11B3 2270 25 95
MENCK (Germany) MHU220Sb 11 500 230 38
MHU300S 16 000 305 40
MHU440S 24 000 440 38
MHU550S 30 000 550 38
MHU660S 36 000 660 32
MHU800S 45 000 800 38
MHU1000S 57 600 1000 38
MHU1700S 94 000 1730 35
MHU2100S 116 500 2140 32
MHU3000S 168 000 3050 32
Vulcana, c (USA) 30C 1360 10 133
50C 2270 21 117
65C 2950 27 117
80C 3630 33 109
85C 3670 35 111
100C 4340 44 103
140C 6350 49 101
Notes
a Air/steam operated.
b S denotes use in shallow water or onshore use;T version is for deep water.
c Differential acting.