1 (314) 869-8600 | www.MVE-STL.com
PILE DRIVING PROCESS
INTRODUCING THE NEW MKT V-8Esc
• Up to 80 Tons of Driving Force
• Standard and High Frequency
Setting Capabilities
• Operates from Wireless Remote
EQUIPMENT
• Excavator Mount – Side Clamp
Vibratory Drivers / Extractors •
Excavator Lead Systems
• Crane Hung Hydraulic Vibratory Drivers
/ Extractors • Hydraulic Auger Systems
• Hydraulic Impact Hammers • Diesel
Hammers • Air Hammers CZM Drill Rigs
SERVICES
• Knowledgeable equipment
applications support • 24/7 parts and
service support
• Custom design and fabrication
using either hand calculations or available
computer software. It is important
to provide as accurate an evaluation as
possible because the preliminary design
based on the static analysis usually forms
the basis for the cost estimate and later
bidding for the project’s piling. The static
analysis provides an estimate of ultimate
pile capacity. Factors of safety are applied
to obtain allowable or design capacity. It
is equally important to ensure the design
will have acceptable levels of settlement.
Select preliminary driving criteria
and hammer energy from wave equation
analysis. In the pile bid package
there may be a single pile type or numerous
pile types, often with the option for
the contractor to provide an alternative
type. In addition to including the pile
parameters (dimension, capacity and
estimated length) in the bid package,
a range of the required driving energy
for the pile hammer is typically provided
to ensure that the contractor has
the right equipment available. To estimate
this driving energy, a preliminary
wave equation analysis is performed to
make sure that the pile is not damaged
during driving (oversized hammer), that
the total driving time needed to achieve
the required capacity is reasonable, and
that the required capacity can actually be
achieved (undersized hammer). The wave
equation analysis provides an estimate
of pile stress during driving. For steel
piles, only compressive stresses need be
evaluated, while both compressive and
tension stresses need to be checked for
concrete piles. The ultimate pile capacity
is reduced by a safety factor to obtain
the allowable or design load; the safety
factor used in the wave equation analysis
should reflect the final method of capacity
verification, typically a dynamic or
static load test.
After the bidding is completed, the
selected contractor is requested to supply
the details of his proposed driving
equipment, including details of the hammer,
hammer system and cushion(s) proposed
for the project. With this data provided,
the initial wave equation analysis
is modified to incorporate the proposed
actual equipment, and the contractor
is either given approval or requested to
select a different hammer. A solution
resulting in acceptable pile stresses and
a final blow count between three and 10
blows per inch is commonly required.
A preliminary driving criterion for the
project is then established.
When the pile is expected to achieve
capacity in a soil bearing layer, some
specifications require that the driving
criterion be met for up to three consecutive
increments (three feet or 250 mm)
to ensure that the pile is well seated in
the bearing layer, especially when driving
a pile to a refusal condition. When
the pile is driven to a hard bedrock, just
confirming the pile is seated on bedrock
is sufficient and continued driving likely
could damage the pile toe or the pile
hammer. The preliminary driving criteria
might include minimum tip elevations
but typically only when piles are designed
to carry tension and lateral loads in addition
to axial compression loads.
Drive probe piles. Up to this point,
the effort has been limited to office desktop
studies. At this stage, for a large piling
project, 10 to 20 locations are selected
across the site to drive probe piles.
Driving probe piles evaluates how the
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