Standard Specifications for Road, Bridge, and Municipal Construction 2020 (M 41-10)

Page 6-172

6-05 Piling

6-05.1 Description

This Work consists of furnishing and driving piles (timber, precast concrete, cast-in-place
concrete, and steel) of the sizes and types the Contract or the Engineer require. This
Work also includes cutting off or building up piles when required. In furnishing and driving
piles, the Contractor shall comply with the requirements of this Section, the Contract, and
the Engineer.

6-05.2 Materials

Materials shall meet the requirements of the following sections:

Reinforcing Steel

9-07

Prestressing Steel

9-07.10

Timber Piling

9-10.1

Concrete Piling

9-10.2

Cast-In-Place Concrete Piling

9-10.3

Steel Pile Tips and Shoes

9-10.4

Steel Piling

9-10.5

Mortar

9-20.4

6-05.3

Construction Requirements

6-05.3(1) Piling Terms

Concrete Piles – Concrete piling may be precast or precast-prestressed concrete, or steel
casings driven to the ultimate bearing resistance called for in the Contract which are filled
with concrete (cast-in-place) after driving.

Steel Piles – Steel piles may be open-ended or closed-ended pipe piles, or H-piles.

Overdriving – Over-driving of piles occurs when the ultimate bearing resistance
calculated from the equation in

Section 6-05.3(12)

, or the wave equation driving criteria

if applicable, exceeds the ultimate bearing resistance required in the Contract in order to
reach the minimum tip elevation specified in the Contract, or as required by the Engineer.

Maximum Driving Resistance – The maximum driving resistance is either the pile ultimate
bearing resistance, or ultimate bearing resistance plus overdriving to reach minimum tip
elevation as specified in the Contract, whichever is greater.

Wave Equation Analysis – Wave equation analysis is an analysis performed using the
wave equation analysis program (WEAP) with a version dated 1987 or later. The wave
equation may be used as specified herein to verify the Contractor’s proposed pile driving
system. The pile driving system includes, but is not necessarily limited to, the pile, the
hammer, the helmet, and any cushion. The wave equation may also be used by the
Engineer to determine pile driving criteria as may be required in the Contract.

Piling 6-05

Ultimate Bearing Resistance – Ultimate bearing resistance refers to the vertical load
carrying resistance (in units of force) of a pile as determined by the equation in

Section

6-05.3(12)

, the wave equation analysis, pile driving analyzer and CAPWAP, static load

test, or any other means as may be required by the Contract, or the Engineer.

Allowable Bearing Resistance – Allowable bearing resistance is the ultimate bearing
resistance divided by a factor of safety. The Contract may state the factor of safety to be
used in calculating the allowable bearing resistance from the ultimate bearing resistance.
In the absence of a specified factor of safety, a value of three shall be used.

Rated Hammer Energy – The rated energy represents the theoretical maximum amount
of gross energy that a pile driving hammer can generate. The rated energy of a pile driving
hammer will be stated in the hammer manufacturer’s catalog or Specifications for that pile
driving hammer.

Developed Hammer Energy – The developed hammer energy is the actual amount of
gross energy produced by the hammer for a given blow. This value will never exceed
the rated hammer energy. The developed energy may be calculated as the ram weight
times the drop (or stroke) for drop, single acting hydraulic, single acting air/steam, and
open-ended diesel hammers. For double acting hydraulic and air/steam hammers, the
developed hammer energy shall be calculated from ram impact velocity measurements or
other means approved by the Engineer. For closed-ended diesel hammers, the developed
energy shall be calculated from the measured bounce chamber pressure for a given
blow. Hammer manufacturer calibration data may be used to correlate bounce chamber
pressure to developed hammer energy. For a single acting diesel hammer the developed
energy is determined using the blows per minute.

Transferred Hammer Energy – The transferred hammer energy is the amount of energy
transferred to the pile for a given blow. This value will never exceed the developed
hammer energy. Factors that cause transferred hammer energy to be lower than the
developed hammer energy include friction during the ram down stroke, energy retained in
the ram and helmet during rebound, and other impact losses. The transferred energy can
only be measured directly by use of sensors attached to the pile. A pile driving analyzer
(PDA) may be used to measure transferred energy.

Pile Driving Analyzer – A pile driving analyzer (PDA) is a device which can measure the
transferred energy of a pile driving system, the compressive and tensile stresses induced
in the pile due to driving, the bending stresses induced by hammer misalignment with the
pile, and estimate the ultimate resistance of a pile at a given blow.

Pile Driving System – The pile driving system includes, but is not necessarily limited to,
the hammer, leads, helmet or cap, cushion and pile.

Page 6-174

Helmet – The helmet, also termed the cap, drive cap, or driving head, is used to transmit
impact forces from the hammer ram to the pile top as uniformly as possible across the
pile top such that the impact force of the ram is transmitted axially to the pile. The term
helmet can refer to the complete impact force transfer system, which includes the anvil
or striker plate, hammer cushion and cushion block, and a pile cushion if used, or just the
single piece unit into which these other components (anvil, hammer cushion, etc.) fit. The
helmet does not include a follower, if one is used. For hydraulic hammers, the helmet is
sometimes referred to as the anvil.

Hammer Cushion – The hammer cushion is a disk of material placed on top of the helmet
but below the anvil or striker plate to relieve impact shock, thus protecting the hammer
and the pile.

Pile Cushion – The pile cushion is a disk of material placed between the helmet and the
pile top to relieve impact shock, primarily to protect the pile.

Follower – A follower is a structural member placed between the hammer assembly,
which includes the helmet, and the pile top when the pile head is below the reach of the
hammer.

Pile Driving Refusal – Pile driving refusal is defined as 15 blows per inch for the last
4 inches of driving. This is the maximum blow count allowed during overdriving.

Minimum Tip Elevation – The minimum tip elevation is the elevation to which the pile tip
shall be driven. Driving deeper in order to obtain the required ultimate bearing resistance
may be required.

6-05.3(2) Ordering Piling

The Contractor shall order all piling (except cast-in-place concrete and steel piles) from
an itemized list the Engineer will provide. This list, showing the number and lengths of
piles required, will be based on test-pile driving (or other) data. The list will show lengths
below the cutoff point. The Contractor shall supply (and bear the cost of supplying) any
additional length required for handling or driving.

The Contractor shall assume all responsibility for buying more or longer piles than
those shown on the list provided by the Engineer. All piles purchased on the basis of
the Engineer’s list but not used in the finished Structure shall become the property
of the Contracting Agency. The Contractor shall deliver these as the Engineer directs.
The Contractor shall keep pile cutoffs that are 8 feet or under and any longer ones the
Contracting Agency does not require.

When ordering steel casings for cast-in-place concrete and steel piling, the Contractor
shall base lengths on information derived from driving test piles and from subsurface
data. The Contractor shall also select the wall thickness of steel piles or steel casings for
cast-in-place piles which will be necessary to prevent damage during driving and handling.
The selection of wall thickness for steel piles or steel casings shall also consider the
effects of lateral pressures from the soil or due to driving of adjacent piles. Steel piles and
steel casings must be strong and rigid enough to resist these pressures without deforming

Piling 6-05

or distorting. The Contractor shall select the wall thickness based on information derived
from test piles, subsurface data and/or wave equation analysis. Wave equation analysis
is required prior to ordering piling for piles with specified ultimate bearing resistances
of 300 tons or greater. If a wave equation analysis is performed, the Contractor shall
base the selection of wall thickness on the maximum driving resistance identified in
the Contract to reach the minimum tip elevation, if the maximum driving resistance is
greater than the specified ultimate bearing resistance and if a minimum tip elevation is
specified. The wave equation analysis shall be submitted by the Contractor as required in

Section 6-05.3(9)A

. The Engineer will not supply any list for piling of these types.

6-05.3(3) Manufacture of Precast Concrete Piling

Precast concrete piles shall consist of concrete sections reinforced to withstand handling
and driving stresses. These may be reinforced with deformed steel bars or prestressed
with steel strands. The Plans show dimensions and details. If the Plans require piles with
square cross-sections, the corners shall be chamfered 1 inch.

Precast or prestressed piles shall meet the requirements of the

Standard Plans

Temporary stress in the prestressing reinforcement of prestressed piles (before loss from
creep and shrinkage) shall be 75 percent of the minimum ultimate tensile strength. (For
short periods during manufacture, the reinforcement may be overstressed to 80 percent
of ultimate tensile strength if stress after transfer to concrete does not exceed 75 percent
of that strength.)

Prestressed concrete piles shall have a final (effective) prestress of at least 1,000 psi.

Unless the Engineer approves splices, all piles shall be full length.

The Contracting Agency intends to perform Quality Assurance Inspection. By its
inspection, the Contracting Agency intends only to facilitate the Work and verify the
quality of that Work. This inspection shall not relieve the Contractor of any responsibility
for identifying and replacing defective material and workmanship.

6-05.3(3)A

Casting and Stressing

Reinforcing bars, hoops, shoes, etc., shall be placed as shown in the Contract, with all
parts securely tied together and placed to the specified spacing. No concrete shall be cast
until all reinforcement is in place in the forms.

The Contractor shall perform quality control inspection. The manufacturing plant for
precast concrete piling shall be certified by the Precast/Prestressed Concrete Institute’s
Plan Certification Program for the type of precast piling to be produced and shall
be approved by WSDOT as a Certified Precast Concrete Fabricator prior to start of
production. WSDOT Certification will be established or renewed during the annual
precast plant review and approval process.

Page 6-176

Prior to the start of production of the piling, the Contractor shall advise the Engineer of
the production schedule. The Contractor shall give the Inspector safe and free access to
the Work. If the Inspector observes any nonspecification Work or unacceptable quality
control practices, the Inspector will advise the plant manager. If the corrective action is
not acceptable to the Engineer, the piling(s) will be subject to rejection by the Engineer.

In casting concrete piles, the Contractor shall:
1. Cast them either vertically or horizontally;
2. Use metal forms (unless the Engineer approves otherwise) with smooth joints and

inside surfaces that can be reached for cleaning after each use;

3. Brace and stiffen the forms to prevent distortion;
4. Place concrete continuously in each pile, guarding against horizontal or diagonal

cleavage planes;

5. Ensure that the reinforcement is properly embedded;
6. Use internal vibration around the reinforcement during concrete placement to

prevent rock pockets from forming; and

7. Cast test cylinders with each set of piles as concrete is placed.

Forms shall be metal and shall be braced and stiffened to retain their shape under
pressure of wet concrete. Forms shall have smooth joints and inside surfaces easy to
reach and clean after each use. That part of a form which will shape the end surface of the
pile shall be a true plane at right angles to the pile axis.

Each pile shall contain a cage of nonprestressed reinforcing steel. The Contractor shall
follow the Contract in the size and location of this cage, and shall secure it in position
during concrete placement. Spiral steel reinforcing shall be covered by at least 1½ inches
of concrete measured from the outside pile surface.

Prestressing steel shall be tensioned as required in

Section 6-02.3(25)C

The Plans specify tensioning stress for strands or wires. Tension shall be measured
by jack pressure as described in

Section 6-02.3(25)C

. Mechanical locks or anchors

shall temporarily maintain cable tension. All jacks shall have hydraulic pressure gauges
(accurately calibrated and accompanied by a certified calibration curve no more than
180 days old) that will permit stress calculations at all times.

All tensioned piles shall be pretensioned. Post-tensioning is not allowed.

The Contractor shall not stress any pile until test cylinders made with it reach a
compressive strength of at least 3,300 psi.

Piling 6-05

6-05.3(3)B Finishing

As soon as the forms for precast concrete piles are removed, the Contractor shall fill
all holes and irregularities with mortar conforming to

Section 9-20.4(2)

mixed at a 1:2

cement/aggregate ratio. That part of any pile that will be underground or below the low-
water line and all parts of any pile to be used in salt water or alkaline soil shall receive only
this mortar treatment. That part of any pile that will show above the ground or water line
shall be given a Class 2 finish as described in

Section 6-02.3(14)B

6-05.3(3)C Curing

Precast Concrete Piles – The Contractor:
1. Shall keep the concrete continuously wet with water after placement for at least

10 days with Type I or II portland cement or at least 3 days with Type III.

2. Shall remove side forms no sooner than 24 hours after concrete placement, and then

only if the surrounding air remains at no less than 50°F for 5 days with Type I or II
portland cement or 3 days with Type III.

3. May cure precast piles with saturated steam or hot air, as described in

Section

6-02.3(25)D

, provided the piles are kept continuously wet until the concrete has

reached a compressive strength of 3,300 psi.

Precast-Prestressed Concrete Piles – These piles shall be cured as required in

Section

6-02.3(25)D

6-05.3(4) Manufacture of Steel Casings for Cast-In-Place Concrete Piles

The diameter of steel casings shall be as specified in the Contract. A full-penetration
groove weld between welded edges is required.

6-05.3(5) Manufacture of Steel Piles

Steel piles shall be made of rolled steel H-pile sections, steel pipe piles, or of other
structural steel sections described in the Contract. A full penetration groove weld
between welded edges is required.

At least 14-days prior to the start of production of the piling, the Contractor shall advise
the Engineer of the production schedule. The Contractor shall give the Inspector safe
and free access to the Work. If the Inspector observes any nonspecification Work or
unacceptable quality control practices, the Inspector will advise the plant manager. If the
corrective action is not acceptable to the Engineer, the piling(s) will be subject to rejection
by the Engineer.

Page 6-178

6-05.3(6) Splicing Steel Casings and Steel Piles

The Engineer will normally permit steel piles and steel casings for cast-in-place concrete
piles to be spliced. But in each case, the Contractor shall submit Type 2 Working Drawings
supporting the need and describing the method for splicing. Welded splices shall be
spaced at a minimum distance of 10 feet. Only welded splices will be permitted.

Splice welds for steel piles shall comply with

Section 6-03.3(25)

and AWS D1.1/D1.1M,

latest edition, Structural Welding Code. Splicing of steel piles shall be performed in
accordance with an approved weld procedure. The Contractor shall submit a Type 2
Working Drawing consisting of the weld procedure. For ASTM A252 material, mill
certification for each lot of pipe to be welded shall accompany the submittal. The ends of
all steel pipe piling shall meet the fit-up requirements of AWS D1.1/D1.1M, latest edition,
Structural Welding Code Section 5.22.3.1, “Girth Weld Alignment (Tubular),” when the
material is spliced utilizing a girth weld.

Splice welds of steel casings for cast-in-place concrete piles shall be the Contractor’s
responsibility and shall be welded in accordance with AWS D1.1/D1.1M, latest edition,
Structural Welding Code. A weld procedure submittal is not required for steel casings
used for cast-in-place concrete piles. Casings that collapse or are not watertight, shall be
replaced at the Contractor’s expense.

6-05.3(7) Storage and Handling

The Contractor shall store and handle piles in ways that protect them from damage.

6-05.3(7)A

Timber Piles

Timber piling shall be stacked closely and in a manner to prevent warping. The ground
beneath and around stored piles shall be cleared of weeds, brush, and rubbish. Piling shall
be covered against the weather if the Engineer requires it.

The Contractor shall take special care to avoid breaking the surface of treated piles.
They shall be lifted and moved with equipment, tools, and lifting devices which do not
penetrate or damage the piles. If timber piles are rafted, any attachments shall be within
3 feet of the butts or tips. Any surface cut or break shall be repaired in accordance with

Section 9-09.3

. The Engineer may reject any pile because of a cut or break.

6-05.3(7)B

Precast Concrete Piles

The Contractor shall not handle any pile until test cylinders made with the same batch of
concrete as the pile reach a compressive strength of at least 3,300 psi.

Storing and handling methods shall protect piles from fractures by impact and undue
bending stresses. Handling methods shall never stress the reinforcement more than
12,000 psi. An allowance of twice the calculated load shall be made for impact and shock
effects. The Contractor shall submit Type 2 Working Drawings consisting of the method
of lifting the piles. The Contractor will take extra care to avoid damaging the surface of
any pile to be used in seawater or alkaline soil.

Piling 6-05

6-05.3(7)C

Steel Casings and Steel Piles

The Engineer will reject bent, deformed, or kinked piles that cannot be straightened
without damaging the metal.

6-05.3(8) Pile Tips and Shoes

The Contracting Agency prefers that timber piles be driven with squared ends. But
if conditions require, they may be shod with metal shoes. Pile tips and shoes shall be
securely attached to the piles in accordance with the manufacturer’s recommendations.

Where called for in the Contract, conical steel pile tips shall be used when driving steel
casings. The tips shall be inside fit, flush-mounted such that the tip and/or weld bead
does not protrude more than

1⁄16

inch beyond the nominal outside diameter of the

steel casing.

If conical tips are not specified, the lower end of each casing shall have a steel driving
plate that is thick enough to keep the casing watertight and free from distortion as it
is driven. The diameter of the steel driving plate shall not be greater than the outside
diameter of the steel casing.

Where called for in the Contract, inside-fit cutting shoes shall be used when driving open-
ended steel piles. The cutting shoes shall be flush-mounted such that the shoe and/or
weld bead does not protrude more than

1⁄16

inch beyond the nominal outside diameter of

the steel pile. The cutting shoe shall be of an inside diameter at least ¾ inch less than the
nominal inside diameter of the steel pile.

Pile tips or shoes shall be of a type denoted in the Qualified Products List. If pile tips
or shoes other than those denoted in the Qualified Products List are proposed, the
Contractor shall submit Type 2 Working Drawings consisting of shop drawings of the
proposed pile tip along with design calculations, Specifications, material chemistry
and installation requirements, along with evidence of a pile driving test demonstrating
suitability of the proposed pile tip. The test shall be performed in the presence of the
Engineer or an acceptable independent testing agency. The test shall consist of driving
a pile fitted with the proposed tip. If the pile cannot be visually inspected (

Section

6-05.3(11)F

), a sacrificial pile fitted with the proposed tip shall be driven outside the

proposed foundation limits. The pile shall be driven to a depth sufficient to develop the
required ultimate bearing resistance as called for in the Contract, in ground conditions
determined to be equivalent to the ground conditions at the project site. For closed-
ended casings or piles, the pile need not be removed if, in the opinion of the Engineer, the
pile can be inspected for evidence of damage to the pile or the tip. For open-ended steel
casings or piles, timber piles or H-piles, the pile shall be removed for inspection.

Page 6-180

6-05.3(9) Pile Driving Equipment

6-05.3(9)A

Pile Driving Equipment Approval

Prior to driving any piles, the Contractor shall submit Type 2 Working Drawings consisting
of details of each proposed pile driving system. The pile driving system shall meet the
minimum requirements for the various combinations of hammer type and pile type
specified in this section. These requirements are minimums and may need to be increased
in order to ensure that the required ultimate bearing resistance can be achieved, that
minimum tip elevations can be reached, and to prevent pile damage.

The Contractor shall submit Type 2E Working Drawings consisting of a wave equation
analysis for all pile driving systems used to drive piling with required maximum driving
resistances of greater than 300 tons. The wave equation analysis shall be performed in
accordance with the requirements of this section and the user’s manual for the program.
The wave equation analysis shall verify that the pile driving system proposed does not
produce stresses greater than 50,000 psi or 90 percent of the yield stress whichever
is less, for steel piles, or steel casings for cast-in-place concrete piles. For prestressed
concrete piles, the allowable driving stress in kips shall be

6-05.3(9)A Pile Driving Equipment Approval

0.095E𝑓𝑓′

plus prestress in

tension, and 0.85f’

minus prestress in compression, where f’

is the concrete compressive

strength in kips per square inch. For precast concrete piles that are not prestressed, the
allowable driving stress shall be 70 percent of the yield stress of the steel reinforcement
in tension, and 0. 85f’

in compression. The wave equation shall also verify that the pile

driving system does not exceed the refusal criteria at the depth of penetration anticipated
for achieving the required ultimate bearing resistance and minimum tip elevation.
Furthermore, the wave equation analysis shall verify that at the maximum driving
resistance specified in the Contract, the driving resistance is 100 blows per foot or less.
Unless otherwise specified in the Contract, or directed by the Engineer, the following
default values shall be used as input to the wave equation analysis program:

Output option (IOUT)

Factor of safety applied to (R

ult

) 1.0

Type of damping

Smith

Residual stress option

ult

is the resistance of the pile used in the wave equation analyses. If the ultimate bearing

resistance equals the maximum driving resistance, a setup factor of 1.3 may be used in
the wave equation analysis to account for pile setup. To use a setup factor in the wave
equation analysis, R

ult

in the analysis is the ultimate bearing resistance divided by 1.3. If

the maximum driving resistance exceeds the ultimate bearing resistance, no setup factor
should be used, and R

ult

is equal to the maximum driving resistance of the pile.

Piling 6-05

Hammer Efficiencies

For Analysis

of Driving

Resistance

For Analysis

of Driving

Stresses

Single acting diesel hammers

0.72

0.84

Closed-ended diesel hammers

0.72

0.84

Single acting air/steam hammers

0.60

0.70

Double acting air/steam hammers

0.45

0.53

Hydraulic hammers or other external combustion hammers

having ram velocity monitors that may be used to assign an

equivalent stroke.

0.85

1.00

Changes to the pile driving system after completion of the Working Drawing review
require a revised Working Drawing Submittal.

6-05.3(9)B

Pile Driving Equipment Minimum Requirements

For each drop hammer used, the Contractor shall weigh it in the Engineer’s presence
or submit a Type 1 Working Drawing consisting of a certificate of its weight. The exact
weight shall be stamped on the hammer. Drop hammers shall weigh not less than:
1. 3,000 pounds for piles under 50 feet long that have an ultimate bearing resistance of

not more than 60 tons, and

2. 4,000 pounds for piles 50 feet and longer or that have an ultimate bearing resistance

of 60 to 90 tons.

If a drop hammer is used for timber piles, it is preferable to use a heavy hammer and
operate with a short drop.

For each diesel, hydraulic, steam, or air-driven hammer used, the Contractor shall submit
a Type 1 Working Drawing consisting of the manufacturer’s Specifications and catalog.
These shall show all data needed to calculate the developed energy of the hammer used.

Underwater hammers may be used only with permission of the Engineer.

Drop hammers on timber piles shall have a maximum drop of 10 feet. Drop hammers
shall not be used to drive timber piles that have ultimate bearing resistance of more than
60 tons.

When used on timber piles, diesel, hydraulic, steam, or air-driven hammers shall provide
at least 13,000 foot-pounds of developed energy per blow. The ram of any diesel hammer
shall weigh at least 2,700 pounds.

Precast concrete and precast-prestressed concrete piles shall be driven with a single-
acting steam, air, hydraulic, or diesel hammer with a ram weight of at least half as much
as the weight of the pile, but never less than the minimums stated below. The ratio of
developed hammer energy to ram weight shall not exceed 6. Steel casings for cast-in-
place concrete, steel pipe, and steel H-piles shall also be driven with diesel, hydraulic,
steam, or air hammers. These hammers shall provide at least the following developed
energy per blow:

Page 6-182

Minimum Developed Energy per Blow (ft-lbs)

Maximum Driving

Resistance (Tons)

Air or Steam

Hammers

Open Ended

Diesel Hammers

Closed Ended

Diesel Hammers

Hydraulic

Hammers

Up to 165

21,500

23,000

30,000

18,500

166 to 210

27,500

29,500

38,000

23,500

211 to 300

39,000

41,500

54,000

33,500

301 to 450

59,000

63,000

81,000

50,500

In addition, the ram of any diesel or hydraulic hammer shall have the following minimum
weights:

Maximum Driving

Resistance (Tons)

Minimum Ram Weight (lbs)

Up to 165

2,700

166 to 210

4,000

211 to 300

5,000

301 to 450

6,500

These requirements for minimum hammer size may be waived if a Type 2E Working
Drawing is submitted consisting of a wave equation analysis demonstrating the ability of
the hammer to obtain the required bearing resistance and minimum tip elevation without
damage to the pile.

Vibratory hammers may be used to drive piles provided the location and plumbness
requirements of this section are met. The required bearing resistance for all piles driven
with vibratory hammers will be determined according to

Section 6-05.3(12)

by driving

the pile at least an additional 2 feet using an impact hammer. This method of determining
bearing resistance will be accepted provided the blows per inch are either constant or
increasing. If the pile cannot be driven 2 feet, the pile will be considered acceptable for
bearing if the pile is driven to refusal.

If water jets are used, the number of jets and water volume and pressure shall be enough
to erode the material next to the pile at the tip. The equipment shall include a minimum
of two water-jet pipes and two ¾ inch jet nozzles. The pump shall produce a constant
pressure of at least 100 psi at each nozzle.

6-05.3(9)C

Pile Driving Leads

All piles shall be driven with fixed-lead drivers. The leads shall be fixed on the top and
bottom during the pile driving operation. Leads shall be long enough to eliminate the
need for any follower (except for timber piles as specified in

Section 6-05.3(11)E

). To

avoid bruising or breaking the surface of treated timber piles, the Contractor shall use
spuds and chocks as little as possible. In building a trestle or foundation with inclined
piles, leads shall be adapted for driving batter piles.

Piling 6-05

A helmet of the right size for the hammer shall distribute the blow and protect the top of
steel piling or casings from driving damage. The helmet shall be positioned symmetrically
below the hammer’s striking parts, so that the impact forces are applied concentric to the
pile top.

Pile driving leads other than those fixed at the top and bottom may be used to complete
driving, if permitted by the Engineer, when all of the following criteria are met:
1. Each plumb and battered pile is located and initially driven at least 20 feet in true

alignment using fixed leads or other approved means.

2. The pile driving system (hammer, cushion and pile) will be analyzed by Pile Driving

Analyzer (PDA) to verify driving stresses in the pile are not increased due to
eccentric loading during driving, and transferred hammer energy is not reduced due
to eccentric loading during driving, for all test piles and at least one production pile
per pier. Unless otherwise specified, the cost of PDA testing shall be incidental to
the various unit Contract prices for driving piles.

6-05.3(10) Test Piles

If the Contract or the Engineer call for it, the Contractor shall drive test piles to determine
pile lengths required to reach the required ultimate bearing resistance, penetration, or
both. Test piles shall be:
1. Made of the same material and have the same tip diameter as the permanent piles

(although test piles for treated timber piles may be either treated or untreated);

2.  Driven with pile tips if the permanent piles will have tips;
3.  Prebored when preboring is specified for the permanent piles;
4.  Identical in cross-section and other characteristics to the permanent piles when

the test piles are steel casings for cast-in-place concrete piles, precast concrete,
precast-prestressed concrete or steel pipe or H-pile;

5. Long enough to accommodate any soil condition;
6. Driven with equipment and methods identical to those to be used for the

permanent piles;

7. Located as the Engineer directs; and
8. Driven before permanent piles in a given pier.

Test piles may also be driven by the Contractor (at no cost to the Contracting Agency) as
evidence that the pile driving system selected will not damage the pile or result in refusal
prior to reaching any specified minimum tip elevation.

Timber test piles shall be driven outside the footing and cut off 1 foot below the finished
ground line. Timber test piles shall not be used in place of permanent piles.

Steel and all types of concrete test piles shall become permanent piles. The Contracting
Agency has reduced the number of permanent piles by the number of test piles.

Page 6-184

The Contractor shall base test pile length on test-hole data in the Contract. Any test piles
that prove to be too short shall be replaced (or spliced if the Contract allows splicing) at
the Contractor’s expense.

In foundations and trestles, test piles shall be driven to at least 15 percent more than the
ultimate bearing resistance required for the permanent piles, except where pile driving
criteria is determined by the wave equation. When pile driving criteria is specified to
be determined by the wave equation, the test piles shall be driven to the same ultimate
bearing resistance as the production piles. Test piles shall penetrate at least to any
minimum tip elevation specified in the Contract. If no minimum tip elevation is specified,
test piles shall extend at least 10 feet below the bottom of the concrete footing or ground
line, and 15 feet below the bottom of the concrete seal.

When any test pile to be left as a permanent pile has been so damaged by handling or
driving that the Engineer believes it unfit for use, the Contractor shall remove and replace
the pile at no additional cost to the Contracting Agency. The Engineer may direct the
Contractor to overdrive the test pile to more than 15 percent above the ultimate bearing
resistance for permanent piles, or if the wave equation is used to determine driving
criteria, the Engineer may direct the Contractor to overdrive the test pile above the
ultimate bearing resistance. In these cases, the overdriving shall be at the Contractor’s
expense. But if pile damage results from this overdriving, any removal and replacement
will be at the Contracting Agency’s expense.

6-05.3(11) Driving Piles

6-05.3(11)A Tolerances

For elevated pier caps, the tops of piles at cut-off elevation shall be within 2 inches of the
horizontal locations indicated in the Contract. For piles capped below final grade, the tops
of piles at cut-off elevation shall be within 6 inches of the horizontal locations indicated
in the Contract. No pile edge shall be nearer than 4 inches from the edge of any footing
or cap. Piles shall be installed such that the axial alignment of the top 10 feet of the
pile is within 4 percent of the specified alignment. No misaligned steel or concrete piles
shall be pulled laterally. A properly aligned section shall not be spliced onto a misaligned
section for any type of pile. Unless the Contract shows otherwise, all piles shall be
driven vertically.

6-05.3(11)B

Foundation Pit Preparation

The Contractor shall replace (and bear the cost of replacing) any pile damaged or
destroyed before or during driving.

The Contractor shall completely dig all foundation pits (and build any required cofferdams
or cribs) before driving foundation piles. The Contractor shall adjust pit depths to allow
for upheaval caused by pile-driving, judging the amount of adjustment by the nature of
the soil. Before constructing the footing or pile cap, the Contractor shall restore the pit
bottom to correct elevation by removing material or by backfilling with granular material.

Piling 6-05

6-05.3(11)C

Preparation for Driving

Treated and untreated timber piles shall be freshly cut square on the butt ends just before
they are driven. If piles will be driven into hard material, caps, collars, or bands shall be
placed on the butt ends to prevent crushing or brooming. If the head area of the pile is
larger than that of the hammer face, the head shall be snipped or chamfered to fit the
hammer. On treated piles, the heads shall be snipped or chamfered to at least the depth
of the sapwood to avoid splitting the sapwood from the pile body.

The Contractor shall match timber pile sizes in any single bent to prevent sway braces
from undue bending or distorting.

When driven, pile faces shall be turned as shown in the Plans or as the Engineer directs.

No precast-prestressed pile shall be driven until test cylinders poured with it reach at
least the specified compressive strength shown in the Contract. On all other precast piles,
the cylinders must reach a compressive strength of at least 4,000 psi before the piles
are driven.

Helmets of approved design shall protect the heads of all precast concrete piles as they
are driven. Each helmet shall have fitted into it a cushion next to the pile head. The
bottom side of the helmet shall be recessed sufficiently to accommodate the required
pile cushion and hold the pile in place during positioning and driving. The inside helmet
diameter shall be determined before casting the pile, and the head of the pile shall be
formed to fit loosely inside the helmet.

Steel Casing, steel pipe or H-piles shall have square-cut ends.

6-05.3(11)D Achieving Minimum Tip Elevation and Bearing

Once pile driving has started, each pile shall be driven continuously until the required
ultimate bearing resistance shown in the Contract has been achieved. Pauses during pile
driving, except for splicing, mechanical breakdown, or other unforeseen events, shall not
be allowed.

If the Contract specifies a minimum tip elevation, the pile shall be driven to at least the
minimum tip elevation, even if the ultimate bearing resistance has been achieved, unless
the Engineer directs otherwise. If a pile does not develop the required ultimate bearing
resistance at the minimum tip elevation, the Contractor shall continue driving the pile
until the required bearing resistance is achieved. If no minimum tip elevation is specified,
then the piles shall be driven to the ultimate bearing resistance shown in the Contract and
the following minimum penetrations:

Pile supporting cross-beams, bents,

elevated pile caps elevation

10 feet below final top of ground

Piles supporting foundations

10 feet below bottom of foundation

Piles with a concrete seal

15 feet below bottom of seal

Page 6-186

If overdriving is required in order to reach a specified minimum tip elevation, the
Contractor shall provide a pile driving system which will not result in damage to the pile
or refusal before the minimum tip elevation is reached. The cost of overdriving shall be
incidental to the various unit Contract prices for furnishing and driving piles.

So long as the pile is not damaged and the embankment or foundation material being
driven through is not permanently damaged, the Contractor shall use normal means
necessary to:
1.  Secure the minimum depth specified,
2.  Penetrate hard material that lies under a soft upper layer,
3.  Penetrate through hard material to obtain the specified minimum tip elevation, or
4.  Penetrate through a previously placed embankment.

Normal means refer to methods such as preboring, spudding, or jetting piles. Blasting or
drilling through obstructions are not considered normal means.

Prebored holes and pile spuds shall have a diameter no larger than the least outside
dimension of the pile. After the pile is driven, the Contractor shall fill all open spaces
between the pile and the soil caused by the preboring or spudding with dry sand, or pea
gravel, or controlled density fill as approved by the Engineer.

If water jets are used, the jets shall be withdrawn before the pile reaches its final
penetration, and the pile shall then be driven to its final penetration and ultimate bearing
resistance. The pile shall be driven a minimum of 2 feet to obtain the ultimate bearing
resistance after the jets are withdrawn, or to refusal, whichever occurs first. If the water
jets loosen a pile previously driven, it shall be redriven in place or pulled and replaced by
a new pile. To check on pile loosening, the Contractor shall attempt to redrive at least one
in every five piles, but no less than one pile per bent or pier.

The various unit Contract prices for driving piles shall cover all costs related to the use
of water jets, preboring, or spudding. The Contracting Agency will not pay any costs the
Contractor incurs in redriving piles loosened as a result of using water jets, preboring,
or spudding.

If the Engineer requires, the Contractor shall overdrive the pile beyond the ultimate
bearing resistance and minimum tip elevation shown in the Contract. In this case, the
Contractor will not be required to:
1.  Use other than normal means to achieve the additional penetration,
2.  Bear the expense of removing or replacing any pile damaged by overdriving, or
3.  Bear the expense of overdriving the pile more than 3 feet as specified in

Section 6-05.5

In driving piles for footings with seals, the Contractor shall use no method (such as jetting
or preboring) that might reduce friction resistance.

Piling 6-05

6-05.3(11)E

Use of Followers for Driving

Followers shall not be used to drive concrete or steel piles. On timber piles, the
Contractor may use steel (not wooden) followers if the follower fits snugly over the pile
head. If a follower is used, the Contractor shall, in every group of 10 piles, drive one long
pile without a follower, but no less than one pile per bent or pier, to the required ultimate
bearing resistance and minimum tip elevation. This long pile shall be used to test the
bearing resistance of the piles driven with a follower in the group. The tip elevation of the
long pile shall be similar to the elevation of the piles driven with the follower. If the tip
elevations are significantly different, as determined by the Engineer, the Contractor shall
redrive the remaining piles in the group to the tip elevation of the longer pile.

6-05.3(11)F

Pile Damage

The Contractor shall remove and replace (and bear the cost of doing so) any pile that is
damaged as determined by the Engineer.

After driving a steel casing for a cast-in-place concrete pile, the Contractor shall leave
it empty until the Engineer has inspected and accepted it. The Contractor shall make
available to the Engineer a light suitable for inspecting the entire length of its interior. The
Engineer will reject any casing that is improperly driven, that shows partial collapse that
would reduce its ultimate bearing resistance, or that has been reduced in diameter, or that
will not keep out water. The Contractor shall replace (and bear the cost of replacing) any
rejected casing.

Pile heads which have been broomed, rolled, or otherwise significantly damaged as
determined by the Engineer shall be cut back to undamaged material before proceeding
with driving as well as final acceptance of the pile.

6-05.3(11)G Pile Cutoff

The Contractor shall trim the tops of all piles to the true plane shown in the Contract and
to the elevation the Engineer requires. If a pile is driven below cutoff elevation without
the Engineer’s permission, the Contractor shall remove and replace it (and bear the costs
of doing so), even if this requires a longer pile. Any pile that rises as nearby piles are
driven, shall be driven down again if the Engineer requires.

Any piles under timber caps or grillages shall be sawed to the exact plane of the Structure
above them and fit it exactly. No shimming on top of timber piles to adjust for inaccurate
pile top elevations will be permitted. If a timber pile is driven out of line, it shall be
straightened without damage before it is cut off or braced.

Steel casing shall be cut off at least 6 inches below the finished ground line or at the low
water line if the casing will be visible as determined by the Engineer.

Standard Specifications for Road, Bridge, and Municipal Construction 2020 (M 41-10) - page 68