Figure 8-14.Assembly of 10- and 20-foot sections.
4. The lines that handle the piles and the hammer
(called the PILE WHIP and the HAMMER WHIP) are
reeved (passed) over the sheaves at the head of the
boom, and the ends are brought down to the foot of the
leads and lashed. Enough slack in each whip is reeved
through to ensure that the boom can be topped up to the
vertical height of the leads without also straining the
5. The leads are raised by topping up the boom.
6. When the leads are raised to the vertical
position, lead braces or spotters (catwalks) are then
7. The hammer is placed in the leads, as shown in
figure 8-16. The leads are raised off the ground by
topping the boom; the hammer is placed under them; the
leads are lowered onto the hammer; and the hammer
whip line is attached to the pin on top of the hammer.
Figure 8-15.Lead adapters connected to the boom tip.
Figure 8-16.Placing hammer in leads.
8. The driving cap or follower block is a cap that
rests on the top of the pile being driven. It slides freely
in the leads to steady the pile and to receive and transmit
the impact of the hammer. The cap, as shown in figure
8-17, has a sling of wire rope, so the cap and the hammer
may be drawn to the top of the leads out of the way when
a pile is being positioned for driving.
The three main types of pile-driving hammers are
the DROP hammer, the STEAM, or PNEUMATIC,
hammer, and the DIESEL hammer. A drop hammer is
a block of metal run up to a specified height and then
dropped on a cap placed on the butt or head of the pile.
Drop hammers weigh from 1,200 to 3,000 pounds.
Figure 8-17.Placing pile cap in leads.