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Pile Driving Safety

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					Pile Driving Safety

                    Crush and NOISE Problems
                The primary tools of the pile driver
              (sometimes called "pilebutts") are the
            sledgehammer, and the can hook which is
             used to position material for installation




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                 It still noise
• Concerns about vibrations during the use of
  driven pile such as auger cast piles and drilled
  shafts. Typically, these concerns regarding
  vibrations and/or noise generated during
  driven pile installation are mostly used in
  urban environments. However, experience has
  shown that vibration and/or noise concerns
  are often overstated and distract from the
  advantages of driven piles.
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        Current OSHA Standards
• 1926.52 Occupational Noise Exposure
   – TABLE D-2 - PERMISSIBLE NOISE EXPOSURES
   Duration per day, hours                      | Sound Level dBA
                                                  slow response
   8...............................……………………..   | 90
   6...............................……………………..   | 92
   4...............................……………………..   | 95
   3...............................……………………..   | 97
   2...............................……………………..   | 100
   1 1/2...........................……………………     | 102
   1...............................……………………..   | 105
   1/2.............................…………………….    | 110
   1/4 or less.....................…………………      | 115
                Mortising        Noise Levels for
               Orb. Sand.
                 Table Saw        Common Tools
                      Planer
                Belt Sander
                        Router
Task/Tool


                     Metal Shear
                        Hand Drill
                       Circular Saw
                             Tile Saw
                       Impact Wrench
                            Miter Saw
                                 Chop Saw
                                    Chain Saw
                                      Hammer Drill
            75 80 85    90 95 100 105 110 115
                                                     Source: NIOSH
         Construction Noise Levels

Pneumatic chip hammer   103-113   Crane                         90-96
Jackhammer              102-111   Hammer                        87-95
Concrete joint cutter   99-102    Gradeall                      87-94
Skilsaw                 88-102    Front-end loader              86-94
Stud welder             101       Backhoe                       84-93
Bulldozer               93-96     Garbage disposal (at 3 ft.)   80
Earth Tamper            90-96     Vacuum cleaner                70


                    Source: Center To Protect Worker’s Rights
Source: Construction Safety Association of Ontario
Noise Controls for Construction Equipment
                          (Schneider et al., 1995)



Equipment                     Noise Controls
Pile Driver                   Enclosure, muffler
Stone saw cutting             Noise control pad with water
Handheld impact drills        Reduction of reflected sound
Circular saw blades           15º tooth angle, new tooth configuration,
                              slotted saw blades, viscoelastic damping
Pneumatic tools               Muffler
Pavement breaker/ Rock        Muffler, enclosure of cylinder case and
drill                         front head, moil damping
Portable air compressor       Muffler, acoustic enclosures
            Incidents happen here
• Four employees were working near pile driving equipment
  preparing to drive the first piling. Apparently the two clips on the
  eye of the hammer hoisting rope slipped, permitting the hammer
  which was still inside the lead to fall some 45 feet. The hammer
  struck a large timber on the ground breaking it. One end of the
  timber struck the employees, fatally injuring one man.
ACCIDENT PREVENTION RECOMMENDATIONS
• That a minimum of four wire rope clips be used to form eyes in the
  ends of wire rope of the size used in accordance with
  1926.251(c)(5) re: Table H-20.
• That the employer instruct each employee in the recognition and
  avoidance of unsafe conditions and the regulations applicable to his
  work environment to correct or eliminate any hazards or other
  exposure to illness or injury in accordance with 1926.21(b)(2).


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          Safety




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 Never Ever




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        Always




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Pile Driving System Components
 Primary                       Crane
 Components:                   Leads
                               Hammer
                               Helmet
                               Cushions
                               Pile Gate
 Components                    Template
 Required in                   Follower
 Special Cases: Jetting Equipment
                               Drilling Equipment
                               Spudding
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                               Equipment
•A pile driver is a mechanical device used to drive piles into soil to provide foundation support
for buildings or other structures. The term is also used in reference to members of the
construction crew that work with pile-driving rigs.
•One traditional type of pile driver includes a heavy weight placed between guides so that it is
able to freely slide up and down in a single line. It is placed upon a pile. The weight is raised,
which may involve the use of hydraulics, steam, diesel, or manual labour. When the weight
reaches its highest point it is then released and smashes on to the pile in order to drive it into
the ground.




   A hydraulic hammer is a modern type of piling hammer used in place of diesel and air
   hammers for driving steel pipe, precast concrete, and timber piles. Hydraulic hammers are
   more environmentally acceptable than the older, less efficient hammers as they generate
   less noise and pollutants.
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                      Vibratory pile hammers contain a system of counter-rotating eccentric
                      weights, powered by hydraulic motors, and designed in such a way that
                      horizontal vibrations cancel out, while vertical vibrations are
                      transmitted into the pile. The pile driving machine is lifted and
                      positioned over the pile by means of an excavator or crane, and is
                      fastened to the pile by a clamp and/or bolts. Vibratory hammers can
                      either drive in or extract a pile; extraction is commonly used to recover
                      steel "H" piles used in temporary foundation shoring. Hydraulic fluid is
                      typically supplied to the driver by a diesel engine powered pump
                      mounted in a trailer or van and connected to the driver head through a
                      set of long hoses. When the pile driver is connected to a dragline
                      excavator, it is powered by the excavator's own diesel engine. Vibratory
                      pile drivers are often chosen to mitigate noise, as when the
                      construction is very close to residence or office buildings




A piling rig is a construction machine for piling in foundation engineering. It is mainly
applied to drill in sandy soil, clay, silty clay, etc. and widely used cast-in-place piles,
diaphragm walls, foundation reinforcement and other foundation projects
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 Drilling rig classification
 1. Mechanical — the rig uses torque converters, clutches, and transmissions powered by
    its own engines, often diesel
 2. Electric — the major items of machinery are driven by electric motors, usually with
    power generated on-site using internal combustion engines
 3. Hydraulic — the rig primarily uses hydraulic power
 4. Pneumatic — the rig is primarily powered by pressurized air
 5. Steam — the rig uses steam-powered engines and pumps (obsolete after middle of
    20th Century)

By pipe used
1. Cable — a cable is used to raise and drop the drill bit
2. Conventional — uses metal or plastic drill pipe of varying types
3. Coil tubing — uses a giant coil of tube and a downhole drilling motor

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                       Pile driving
• Drop hammer – ancient pile driver F10-5
  – Pile driver is usually crane driven
  – Pile driver consists of a
     •   Drop weight
     •   Leads – guide for weight
     •   Pile driving consists of placing a pile in the lead
     •   Dropping the weight
     •   Lifting weight
     •   Repeat
     •   Must have a stop block to keep weight on leads

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                      Pile Driving
                      System
Lead
                                 Boom
Hammer

Helmet

Monkey
                                                        Crane
Pile
                 Spotte
                 r
Pile Gate



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          Swinging Lead

  Lead
                                                 Boom
 Hammer


  Helmet
                                                        Crane


   Pile


                                      Stabbing
   Pile Gate                          Points



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  Swinging Lead

       Lead       Platfor
                  m


Hamm
er




   American or Box Lead


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  Swinging Lead

                           Lead




Hamm
er




  European or Truss
  Lead           P bar Y Safety Consultants Alberta Canada
                     Fixed Lead



     Lead
                                                     Boom
     Hamme
     r
     Helmet                                                 Crane



      Pile
                                            Spotte
      Pile Gate                             r


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                                 Piles
• Column driven into soil
  – Common types
     • Timber – inexpensive, easy to cut & splice, no special
       handling
        – Max length = 100’, load carrying limited, pile ends may
          splinter, subject to insects and decay
        – Can use pressure treated
        – Good underwater
     • Precast concrete piles
        – Come in almost any size and shape – round, square ,
          octagonal

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                            Piles
• Precast concrete piles
   – Come in almost any size and shape – round, square ,
     octagonal
   – High strength, no decay
   – Heaviest type of pile, brittle, no tensile strength
   – Need careful handling, hard to cut & splice
• Cast in Place Piles
   – Shell piles – steel shell driven into ground and then concrete
     poured in
   – Steel serves as additional reinforcement
   – Types = uniform taper, step taper and straight
   – Light, easy to handle, easy to cut & splice

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                               Piles
• Steel Piles
    –   Capable of heavy loads
    –   Driven to great depths, easy to cut & splice,
    –   Common types = H-piles, pipe piles
    –   High cost
• Composite piles
• Made from 2+ materials
    – Timber bottom, steel top
    – Won’t decay
• Bulb piles


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                       Pile driving
• Drop hammer – ancient pile driver F10-5
  – Pile driver is usually crane driven
  – Pile driver consists of a
     •   Drop weight
     •   Leads – guide for weight
     •   Pile driving consists of placing a pile in the lead
     •   Dropping the weight
     •   Lifting weight
     •   Repeat
     •   Must have a stop block to keep weight on leads

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• Power Hammer Pile Drivers
  – Use a working fluid to drive hammer
  – Steam or compressed air was first type used
  – Hydraulic is newer version
  – Single acting hammer
     • Fluid lifts weight which then falls down
  – Double acting hammer
     • Fluid lifts weight and drive weight down
     • Hammer Lighter than single acting

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Diesel Hammer
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            Hammer Types
Drop



Air                  Single acting
                     Double acting
                     Differential acting

Diesel
                     Single acting (open end) Most Common
                     Double acting (closed end)


Hydraulic
                     Single acting
                     Double acting

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Drop Hammers
Features

 Ram raised by crane line

 Efficiency of drop
 controlled by operator
 and system
Comments

 • Low equipment
 cost       • Slow operation
 • Simple   • Inconsistent
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     Single Acting Air
        Hammers
Features
External compressor supplies
power
Relatively heavy ram, short stroke
Stroke controlled by 1 or 2 slide
bar setting: 3 ft, 3 or 5 ft, 2 or 4 ft

Comments

Air pressure, volume, and soil
resistance can influence actual
stroke by as much as 3 to 6 inches
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Double Acting Air Hammer Consultants Differential Acting Air Hammer
      Single Acting Diesel Hammers
Features

Variable fuel settings

Relatively light ram, long stroke

Potential energy = Wh

Most common hammer type

Comments

Stroke depends on:
   • fuel input
   • pile stiffness
   • soil resistance bar Y Safety Consultants Alberta Canada
                    P
One Piece Pipe Pile Helmet




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        Hammer Cushions

Materials placed between the pile hammer
ram and the helmet to relieve impact shock
and thereby protect the hammer while at
the same time transmit consistent energy
to the pile



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Hammer Cushions



                                            Conbest (Phenolic fiber)
                                             and aluminum plates




    Blue Nylon   P bar Y Safety Consultants Alberta Canada
                                              Aluminum and Micarta
H-pile Helmet and Hammer
      Cushion Section




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              Pile Cushions
• Concrete piles require a pile cushion between
  the helmet and the pile lead

• Typically made of plywood, hardwood,
  plywood & hardwood composites, or other
  man-made materials

• Typical thickness 4 inches (min) to 12 inches or
  more


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                     Predrilling

• Soil augers or drills used where jetting is
  inappropriate / ineffective to
      - Penetrate obstructions, boulders, debris fills
      - Facilitate pile placement through embankments
      - Reduce ground movements


• Predrilled hole diameter 4 inches less than diagonal
  of square pile, or 1 inch less than diameter of
  round pile
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                    Spudding
• The act of opening a hole through dense
  material by driving or dropping a short &
  strong member & then removing it

• Used as an alternate to jetting or predrilling in
  upper soil consisting of miscellaneous fill



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• Pile foundation used to support structure
   – poor quality soil
      • bearing capacity failure
      • excessive settlement
• End-bearing pile
      • Pile driven until it comes to rest on a hard impenetrable
        layer of soil or rock
• Friction pile
      • load of the structure must come from the skin friction or
        adhesion between surface of the pile and the soil
                Pile Load Tests
• Design based on estimated loads and soil
  characteristics
• Load test piles
  – Hydraulic jack
  – static weight
     • bearing failure
     • excessive settlement
        Pile Groups and Spacing
• Piles placed in groups of three or more
• Pile groups tied together by a pile cap
  – attached to the head of the individual piles and
    causes several piles to work together.
• Pile spacing
  – minimum spacing
     • driven in rock
     • Not driven in rock
  Construction of Pile Foundations
• Piling types
  – Timber, concrete and steel
• Pile hammers
  – Top of the Pile
     • Cap, cap-block and cushion
  – Hammer-Pile systems
  – Base of the Pile
     • Driving shoes
             Drilled Caissons
• Deep foundation that is constructed in-
  place
  – Drilling and casting concrete in-place
     • straight-shaft
     • belled ( reduced contact pressure)
• Advantages
  – lighter and less expensive drilling equipment
  – quieter than pile drivers
  – reduce ground vibrations
  – visual inspection of subsoil
     Bearing Capacity of Caissons
• Q(ult) = Q(friction) + Q(tip)
• Cohesive soils
  – Q(total) = cNc *A(bottom) + f*A(shaft)
      • Ex. 11-1
• Cohesionless soils
  – Q(ult) = p(v)*Nq*A(bottom) + (Ko*p(v)*tan )A(shaft)
      • Ex. 11-3
• Bedrock
  – Ex. 11-4
          Lateral Earth Pressure
• “sideways pressure” of soil
  – Retaining walls, bulkheads and abutments
• Soil pressure at rest, P(o)
  – “sideways” pressure exerted by earth that is
    prevented from movement by an unyielding wall
• Active soil pressure, P(a)
  – “sideways” pressure exerted by earth that pushes
    the wall away from the soil
Resultant = P(o) and location of resultant H/3
When part of the wall is below the water table:
Hydrostatic water pressure must be added to “effective” lateral
soil pressure to obtain the total (AT REST) soil pressure, P(o).
            Active soil pressure
• Rankine soil pressure
  – vertical smooth walls
     • no adhesion or friction between wall and soil
• Lateral soil pressure varies linearly with depth
  – resultant acts at a distance of 1/3 the vertical
    distance from the heel of the wall and the
    resultant is parallel to the backfill surface.
If the backfill surface is level and  = 0, the equation simplifies
to:

K(a) = 1- sin /1 + sin 

where:
K(a) is the coefficient of active earth pressure
 is the angle of internal friction of the backfill soil
            Retaining Structures
• Structure constructed to hold back a soil mass
  – Concrete walls
     • gravity wall
        – plain concrete
     • cantilever wall
        – steel reinforced

• Design based on active earth pressure, P(a)
• Stability analysis
  – horizontal (sliding) movement
  – vertical (settlement) movement
  – rotation (overturning)
     •   MOMENTS calculated about the TOE of the wall
     •   FS = M(t)/M(overturnring)
     •   FS = 1.5 for cohesionless soils
     •   FS = 2.0 for cohesive soils
Soil type 1 = clean sand and gravel
Any Questions




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