96E09/22/06

S551-96E.doc

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  Include the following when driven piles are specified.

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**Section 551. - DRIVEN PILES**

**551.03 Pile Driving Equipment**

**(a) Pile Hammers**

> **(5) Nonimpact hammers.** [Delete the first sentence and substitute
> the following:]{.underline}
>
> Use nonimpact hammers, such as vibratory hammers, only when permitted
> in writing or when specified in the contract.
>
> [Add the following:]{.underline}
>
> **(6) Hydraulic hammers.** Provide a power plant for hydraulic hammers
> with sufficient capacity to maintain the volume and pressure,
> specified by the manufacturer, at the hammer under working conditions.
> Equip the power plant and equipment with accurate pressure gauges that
> are easily accessible to the CO.

**(b) Approval of pile driving equipment.** [Delete the second and third
paragraphs and substitute the following:]{.underline}

Approval of pile driving equipment will be based on a wave equation
analysis unless the contract specifies the dynamic formula to determine
the ultimate driven pile capacity. If the contract specifies the dynamic
formula, approval of pile driving equipment will be based on minimum
hammer energy in Table 551-1. The CO will evaluate the proposed
equipment and accept or reject the driving system within 14 calendar
days of receipt of the pile and driving equipment information.

Use only the approved equipment during pile driving operations. Approval
of the pile driving system is specific to the equipment submitted. If
the proposed equipment is modified or replaced, re-evaluate and resubmit
the analysis and revised data for approval before using. The CO will
accept or reject the revised driving system within 14 days of receipt of
the revised submittal. Approval of a pile hammer does not relieve the
Contractor of responsibility for piles damaged due to driving stress.

> **(1) Equipment submittal.** [Delete the first paragraph and
> substitute the following:]{.underline}
>
> Submit the following pile driving equipment information to the CO at
> least 30 days before driving piles. Include a wave equation analysis
> for the proposed pile driving system, unless the contract specifies
> the use of the dynamic formula to determine the ultimate driven pile
> capacity. Use a professional engineer with at least 3 years experience
> in wave equation analyses to perform the wave equation analysis.
> Submit a resume of the engineer for approval.

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  Include subsection 551.03(b)(2) if wave equation analysis is required.

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> **(2) Wave equation.** [Delete the first paragraph and substitute the
> following:]{.underline}
>
> The required number of hammer blows indicated by the wave equation at
> the ultimate pile capacity shall be between 3 and 10 per inch.
>
> Use the following hammer efficiencies in the wave equation analysis
> unless more specific hammer efficiency information is available:

  ------------------------------------ ----------------------------------
  **Hammer Type**                      **Efficiency in Percent**

  Single acting air/steam              67

  Double acting air/steam              50

  Diesel                               72
  ------------------------------------ ----------------------------------

> In addition, the pile stresses resulting from the wave equation
> analysis shall not exceed the values at which pile damage is
> impending. The point of impending damage is defined for steel,
> concrete, and timber piles as follows.
>
> *(b) Concrete piles.* [Delete the subparagraph and substitute the
> following:]{.underline}
>
> Limit the tensile (*TS*) and compressive (*CS*) driving stresses to:
>
> *TS* ≤ 0.25*fc\'* ^1/2^ + EPV
>
> *CS* ≤ 0.85*fc\'* - EPV
>
> Where:
>
> *fc\'* = The 28-day design compressive strength of the concrete in
> pounds.
>
> EPV = The effective prestress value in pounds.

**(c) Driving appurtenances.** [Add the following:]{.underline}

> **(6) Pile cushion.**
>
> For concrete piles, use a new pile cushion to protect the head of each
> pile. Cut the pile cushion at least 4 inches thick and to match the
> cross-section of the pile top. Replace the pile cushion if it is
> compressed more than one-half its original thickness or it begins to
> burn. For steel and timber piles, protect each pile with an approved
> driving cap. Enclose timber piles with approved collars or bands to
> prevent splitting or brooming. Replace caps when damaged. Do not reuse
> cushions or caps.
>
> **(7) Pile shoes.** When specified, provide shoes to protect the
> pile-tip from damage during driving. Fabricate all shoes to snugly fit
> the pile tip. For concrete piles, attach the shoe to the pile using
> dowels or other approved methods. For steel piles, design and fit the
> shoe to the steel shape and weld the shoe to the pile so as not to
> stress the web or the flange. For timber piles, carefully shape the
> tip to secure an even uniform bearing for the pile shoe. Treat all
> holes, cuts, or caps in treated timber piles with 2-brush applications
> of creosote-coal tar solution.

**551.06 Driven Pile Capacity.** [Delete the second paragraph and
substitute the following:]{.underline}

Use the wave equation to determine ultimate pile capacity of the
in-place pile.

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  Include subsection 551.07 when pre-boring is approved for the project

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**551.07 Preboring.** [Delete the first and second paragraphs and
substitute the following:]{.underline}

Use auguring, wet rotary drilling, or other approved methods of
preboring.

In compacted embankments more than 5 feet deep, prebore the pile hole to
natural ground. Prebore holes 6 inches greater than the diameter of the
pile. For square, rectangular or H piles, make the diameter of the hole
equal to the diagonal of the pile cross-section plus 6 inches.

For piles end-bearing on rock or hardpan, preboring may extend to the
surface of the rock or hardpan. Seat the pile into the end-bearing
strata.

For piles not end-bearing on rock or hardpan, stop preboring at least 5
feet above the estimated pile tip elevation and drive the pile with an
impact hammer to a penetration which achieves the required ultimate pile
capacity. Prebore holes smaller than the diameter or diagonal of the
pile cross-section while allowing penetration of the pile to the
specified depth.

If subsurface obstructions such as boulders or rock layers are
encountered, the hole diameter may be increased to the least dimension
adequate for pile installation. Fill any void space remaining around the
pile after completion of driving with sand or other approved material.
Do not use a punch or a spud in lieu of preboring.

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  Include subsection 551.08 when driven piles are specified.

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**551.08 Preparation and Driving**. [Delete the first and second
paragraphs and substitute the following:]{.underline}

Perform the work under Section 208. Make the heads of all piles plane
and perpendicular to the longitudinal axis of the pile. Coordinate pile
driving to prevent damage to other parts of the completed work.

Drive piles to within 3 inches of plan location at cutoff elevation.
Drive piles no closer than 6 inches from any cap face. Drive piles so
that the axial alignment is within ¼ inch per foot, along the
longitudinal axis, of the required alignment. The CO may stop driving to
check the pile alignment. Check alignment of piles that cannot be
internally inspected after installation before the last 5 feet are
driven. Do not pull laterally on piles or splice to correct
misalignment. Do not splice a properly aligned section on a misaligned
pile.

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  Include subsection 551.08(a) when timber piles are specified.

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**551.08 Preparation and Driving.**

**(a) Timber piles.** [Delete the second paragraph.]{.underline}

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  Include subsection 551.08(c) when precasted or prestressed concrete
  piles are specified.

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**551.08 Preparation and Driving.**

**(c) Precast and prestressed concrete piles.** [Delete the second and
third paragraphs and substitute the following:]{.underline}

Reject concrete piles with reduced strength caused by external defects
such as spalls or cracks or internal defects such as cavities revealed
with non-destructive testing.

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  Include subsection 551.09(b) when pile splices are approved for
  concrete piles.

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**551.09 Splices.**

**(b) Concrete pile splices.** [Delete the text and substitute the
following:]{.underline}

Use dowels or other acceptable mechanical means to splice precast
concrete or precast prestressed concrete piles. Submit drawings of
proposed splices for acceptance.

If dowels are used, cast the dowels into the tip end of the following
pile with corresponding holes at the butt end of the driven pile.
Serrate the holes to provide a mechanical bond. Separate the ends of the
piles by at least ½ inch. Clean all surfaces and dowel holes. Grout the
dowels in place and allow the grout to cure. Enclose the gap with forms
and inject a bonding agent capable of withstanding the impact and
driving forces and having the same compressive strength as the pile.
Follow the manufacturer\'s recommendations regarding the use and curing
of grouting and bonding products.

Attach manufactured splices to the concrete piles as recommended by the
manufacturer. The splice shall develop strengths in compression,
tension, and bending equal to or exceeding the strength of the pile
being spliced.

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  Include subsection 551.11(a) when driven piles are specified.

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**551.11 Pile Load Tests.**

**(a) Dynamic load test.** [Delete the second and fifth
paragraphs.]{.underline}

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  Include subsection 551.12(a) when driven piles are specified.

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**551.12 Pile Cutoffs.**

**(a) Steel piles.** [Delete the fourth and fifth sentences and
substitute the following:]{.underline}

Paint piles before driving. Use one prime coat and 2 finish coats on
trestles or other exposed piling to at least 3 feet below the finished
groundline or waterline.