USACE / NAVFAC / AFCESA / NASA UFGS-31 62 21 (November 2008)
-----------------------------
Preparing Activity: USACE Superseding
UFGS-31 62 21 (April 2006)
UNIFIED FACILITIES GUIDE SPECIFICATIONS
References are in agreement with UMRL dated January 2009
SECTION 31 62 21
PILING: COMPOSITE, WOOD AND CAST IN-PLACE CONCRETE
11/08
NOTE: This guide specification covers the requirements for composite, wood
and cast-in-place concrete piles.
Edit this guide specification for project specific requirements by adding, deleting,
or revising text. For bracketed items, choose applicable items(s) or insert
appropriate information.
Remove information and requirements not required in respective project, whether
or not brackets are present.
Comments and suggestions on this guide specification are welcome and should
be directed to the technical proponent of the specification. A listing of technical
proponents, including their organization designation and telephone number, is
on the Internet.
Recommended changes to a UFGS should be submitted as a Criteria Change Request
(CCR).
PART 1 GENERAL
1.1 UNIT PRICES
1.1.1 Piling
Piling will be paid at the contract unit price per linear m foot (including test piles), for "Piling" multiplied
by the total linear m feet of acceptable piles actually installed. The Contracting Officer reserves the right
to increase or decrease the total length of piles to be furnished and installed by changing the foundation pile
locations or elevations, requiring the installation of additional piles, or requiring omission of piles. Payment
will constitute full compensation for furnishing, delivering, handling, and installing the foundation piles.
The Contractor will not be allowed payment for withdrawn, broken, or rejected piles or (except for test piles)
for any portion of any pile remaining above the cut-off point.
1.1.2 Load Test
The contract includes [_____] metric ton -ton pile load tests. The Contracting Officer reserves the right to
increase or decrease the number of load tests. Adjustments in the contract price will be made for such increases
or decreases by the contract price for "Additional Pile Load Test" or "Omitted Pile Load Test."
1.1.3 Pile Withdrawals
Pile Withdrawals will be paid at the contract unit price each for "Pile Withdrawals" multiplied by the number
of piles withdrawn as directed. The Contracting Officer reserves the right to increase or decrease the number
of pile withdrawals. Adjustments in the contract price will be made in accordance with the CONTRACT CLAUSES.
1.1.4 Basis of Payment
NOTE: This paragraph anticipates bids on a lump sum price, with directed changes
in accordance with the CONTRACT CLAUSES or with the unit prices defined above.
Where the contract is based on unit price, this paragraph should be deleted
and replaced by the following paragraph:
The contract price for piling will include the cost of all necessary equipment, tools, material, labor, and supervision
required to: deliver, handle, install, cut off, and withdraw the piles (including test piles), and conduct the
load tests. Payment for piles will be based on the lengths of acceptable piles measured from cut-off elevations
to final tip elevations. No additional payment will be made for: damaged, rejected, or misplaced piles, withdrawn
piles, other than test piles withdrawn as directed, any portion of a pile remaining above the cut-off elevation,
backdriving, cutting off piles, splicing, build-ups, or any cut-off lengths of piles.
1.1.4.1 Piling Quantities
The contract price for piling, including [_____] test piles, will be based on the following quantities and will
include [_____] -metric ton -ton load tests and [_____] test pile withdrawals.
Total
Size Length
Number of Piles (mm) m
_______________ ____________ __________
[_____] [_____] [_____]
Total
Size Length
Number of Piles (inches) (feet)
_______________ ____________ __________
[_____] [_____] [_____]
1.1.4.2 Variations in Pile Quantities
Based on the results of driving and loading the test piles, the Contracting Officer will determine and will list
for the Contractor calculated pile tip elevations and the minimum driving resistances for all piles. The Contracting
Officer reserves the right to increase or decrease the total length of piles to be furnished and installed by
changing the pile locations or elevations, requiring the installation of additional piles, or directing the omission
of piles from the requirements shown and specified. Should the total length of piles installed vary from that
specified because of added or omitted piles or variations in the pile lengths, the contract price for piling
will be adjusted by the applicable contract unit price per linear meter foot (by size) for "Additional Pile Length"
or "Omitted Pile Length" and multiplied by the actual length added or omitted.
1.1.4.3 Variations in the Number of Pile Load Tests
The Contracting Officer reserves the right to increase or decrease the number of pile load tests from that specified.
For each load test added or deleted, the contract price will be adjusted by the applicable contract unit price
for "Each Additional Pile Load Test" or "Each Omitted Pile Load Test."
1.1.4.4 Variations in Test Pile Withdrawals
Should the number of test pile withdrawals be increased above the specified number at the direction of the Contracting
Officer, the contract price for piling will be adjusted by the contract price for "Each Additional Test Pile
Withdrawn" and multiplied by the number of additional test piles withdrawn.
1.2 REFERENCES
NOTE: This paragraph is used to list the publications cited in the text of
the guide specification. The publications are referred to in the text by basic
designation only and listed in this paragraph by organization, designation,
date, and title.
Use the Reference Wizard's Check Reference feature when you add a RID outside
of the Section's Reference Article to automatically place the reference in the
Reference Article. Also use the Reference Wizard's Check Reference feature
to update the issue dates.
References not used in the text will automatically be deleted from this section
of the project specification when you choose to reconcile references in the
publish print process.
The publications listed below form a part of this specification to the extent referenced. The publications are
referred to within the text by the basic designation only.
[AMERICAN ASSOCIATION OF STATE HIGHWAY AND TRANSPORTATION OFFICIALS (AASHTO)AASHTO M 133(2008) Standard Specification for Preservatives and Pressure Treatment Processes for Timber][AMERICAN WELDING SOCIETY (AWS)AWS D1.1/D1.1M(2008) Structural Welding Code - SteelAWS D1.4/D1.4M(2005; Errata 2005) Structural Welding Code - Reinforcing Steel][ASTM INTERNATIONAL (ASTM)ASTM A 615/A 615M(2008b) Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete ReinforcementASTM A 996/A 996M(2006a) Standard Specification for Rail-Steel and Axle-Steel Deformed Bars or Concrete ReinforcementASTM D 1143/D 1143M(2007) Piles Under Static Axial Compressive LoadASTM D 25(1999; R 2005) Round Timber Piles]1.3 SYSTEM DESCRIPTION
The work shall be performed by a Contractor specializing in the required foundation system and having experience
installing the specified foundation system under similar subsurface conditions.
1.3.1 Subsurface Data
Subsurface soil data logs are [shown on the drawings] [appended to the SPECIAL CONTRACT REQUIREMENTS]. The subsoil
investigation report and samples of material taken from subsurface investigations may be examined at [_____].
1.3.2 Equipment
1.3.2.1 Pile Hammer
Provide a hammer with a delivered energy suitable for the total weight of the pile, the character of subsurface
material to be encountered, and the pile capacity to be developed. The driving energy of the hammer shall be
not less than 20.3 kN-m 15,000 foot-pounds. Operate diesel-powered hammers at the rate recommended by the manufacturer
throughout the entire driving period. Maintain sufficient pressure at the steam hammer so that:
a. For a double-action hammer, the number of blows per minute during and at the completion of driving
of a pile is equal approximately to that at which the hammer is rated;
b. For a single-acting hammer, there is full upward stroke of the ram; and
c. For a differential type hammer, there is a slight rise of the hammer base during each upward stroke.
1.3.2.2 Driving Helmets or Caps
a. Use a driving helmet or cap, including a pile cushion, between the top of the pile and the ram to
prevent impact damage to the pile. The driving helmet, or cap and pile cushion combination, shall completely
cover the top surface of the pile and be capable of protecting the head of the pile, minimizing energy
absorption and dissipation, and transmitting hammer energy uniformly over the top of the pile.
b. The driving helmet or cap shall fit loosely around the top of the pile so that the pile is not restrained
by the driving cap, if the pile tends to rotate during driving. The pile cushion may be of solid wood,
of laminated construction using plywood, softwood, or hardwood boards, or of other approved cushioning
material. The pile cushion shall be retained by the driving helmet.
c. The minimum thickness of the pile cushion shall be 75 mm 3 inches and the thickness shall be increased
so as to be suitable for the size and length of pile, character of subsurface material encountered, hammer
characteristics, and required driving resistance. Use a new pile cushion at the start of driving for
each pile and replaced whenever it becomes highly compressed, charred, burned, or deteriorated in any
manner during driving.
1.4 SUBMITTALS
NOTE: Review submittal description (SD) definitions in Section 01 33 00 SUBMITTAL
PROCEDURES and edit the following list to reflect only the submittals required
for the project. Submittals should be kept to the minimum required for adequate
quality control.
A “G” following a submittal item indicates that the submittal requires Government
approval. Some submittals are already marked with a “G”. Only delete an existing
“G” if the submittal item is not complex and can be reviewed through the Contractor’s
Quality Control system. Only add a “G” if the submittal is sufficiently important
or complex in context of the project.
For submittals requiring Government approval on Army projects, a code of up
to three characters within the submittal tags may be used following the "G"
designation to indicate the approving authority. Codes for Army projects using
the Resident Management System (RMS) are: "AE" for Architect-Engineer; "DO"
for District Office (Engineering Division or other organization in the District
Office); "AO" for Area Office; "RO" for Resident Office; and "PO" for Project
Office. Codes following the "G" typically are not used for Navy, Air Force,
and NASA projects.
Choose the first bracketed item for Navy, Air Force and NASA projects, or choose
the second bracketed item for Army projects.
Government approval is required for submittals with a "G" designation; submittals not having a "G" designation
are for [Contractor Quality Control approval.][information only. When used, a designation following the "G"
designation identifies the office that will review the submittal for the Government.] Submit the following in
accordance with Section 01 33 00 SUBMITTAL PROCEDURES:
SD-02 Shop Drawings
Equipment
Detail drawings, to demonstrate compliance of driving equipment, including [metal shoes and]
cap blocks, splicing of timber and concrete sections, and the forming, reinforcing and casting
of piles.
SD-03 Product Data
Pile Driving
A complete and accurate record of each driven pile indicating the pile location (as driven),
size, length, final elevations of tip and top, elevation of top of wood section, pile weight,
number of splices and locations, blows required for each m foot of penetration throughout the
entire length of the pile and for the final 150 mm 6 inches of penetration, and the total driving
time. The record should also include the type and size of the hammer used, the rate of operation,
and the type and dimensions of the driving helmet and cushion block used. Record any unusual
conditions encountered during pile installation and immediately report them to the Contracting
Officer.
SD-06 Test Reports
Field Test and Inspections
A complete report on the pile test, within [seven] [_____] days of completion of each pile
test, including, but not limited to, a description of the pile driving equipment, driving records
for both test piles and reaction piles, complete test data, analysis of test data, and recommended
allowable design loads based on the pile test results. Prepare the report by or under the direct
supervision of a registered professional engineer experienced in pile load testing and load
test analysis.
1.5 DELIVERY, STORAGE, AND HANDLING
Piles shall be stored and handled avoiding overstress or any other condition that may cause injury to the piles.
Untreated piles to be stored for an extended period of time shall be inspected periodically, as well as shortly
before driving, to detect damage due to fungus and insect attack. If treated piles are to be stored in a horizontal
position for an extended period of time, they shall be inspected periodically to ensure that the treatment does
not seep to the lower half of the pile to the extent that the upper half does not contain a sufficient amount
of treatment.
PART 2 PRODUCTS
2.1 PILES
2.1.1 Wood Sections
Sections of the wooden piles shall be not less than [_____] mm inches in diameter at the butt (before forming
of the tenon). Provide Douglas Fir or Southern Pine piles [clean peeled][rough peeled] conforming to ASTM D 25
. Piles shall [be pressure treated in accordance with AASHTO M 133, for Land and Fresh Water Piles by Pressure][not
be treated].
2.1.2 Metal Shells
Provide metal shells of steel of sufficient strength and rigidity to withstand all driving stresses, to prevent
distortion caused by driving adjacent piles, to prevent collapse due to soil or hydrostatic pressure, and to
maintain their shape, free from dents or deformation. Thickness of shells shall be as indicated. Provide watertight
shells to exclude groundwater during concrete placement. The actual or superficial perimeter of a cross section
of the piles, at any point in their length, shall be circular. Design the joint as specified herein, and in
a manner to prevent the entrance of soil while driving, the leaking of concrete during placing, and the entrance
of water at a rate that would not allow the shell to be properly dewatered before placement of concrete. The
shells shall be [step-tapered type with a minimum nominal diameter of [_____] mm inches at the joint between
wood and shell and the diameter shall increase from the joint to the cut-off elevation at a rate of not less
than 10 mm per meter 1 inch per 8 feet of length] [or] [constant-section shells with a minimum nominal diameter
of [_____] mm inches].
2.1.3 Concrete
Materials, mixing, and placing of concrete shall conform with the requirements of Section 03 31 00.00 10 CAST-IN-PLACE
STRUCTURAL CONCRETE. Concrete shall have a minimum compressive strength of [_____] MPa psi at 28 days using
[_____] -mm -inch maximum-size coarse aggregate. Slump shall be [_____] to [_____] mm inches for manual compaction
and [_____] to [_____] mm inches when concrete is mechanically vibrated.
2.1.4 Reinforcing Steel
Provide reinforcing steel of the dimensions and sizes indicated and complying with [ASTM A 615/A 615M, Grade
[40] [60]] [ASTM A 996/A 996M, Grade [50] [60]].
PART 3 EXECUTION
3.1 PILE DRIVING
NOTE: Past experience with similar structures is probably the best indicator
of the need for protection. If protection is to be provided, this paragraph
should be expanded to cover the type and extent of protection required. The
following typical references offer detailed information on different types of
pile protection:
a. Design and Construction of Ports and Marine Structures, by Alonzo DeF. Quinn,
McGraw-Hill Book Company, New York, 1961.
b. Cathodic Protection, by L. M. Applegate, McGraw-Hill Book Company, New York,
1960.
c. Protection of Piling in Marine Environments, published by US Steel Corporation.
Additionally, the Construction Engineering Research Laboratory in Champaign,
Illinois has done extensive research on pile protection, and may be contacted
for information.
Perform driving with fixed leads to hold the pile firmly in position, alignment, and in axial alignment with
the hammer. Drive piles to or below the "calculated" tip elevation to reach a driving resistance in accordance
with the schedule that the Contracting Officer will prepare from the load test results.
a. The pile hammer used for driving shall be the same type, operated at the same rate and in the same
manner, as that used for driving the test piles. If a pile fails to reach the "calculated" tip elevation
or if a pile reaches the "calculated" tip elevation without reaching the required driving resistance,
notify the Contracting Officer and perform corrective measures as instructed.
b. No piles shall be driven until the excavation or fill in the area that piles are to occupy has been
completed to within 305 mm 12 inches of the grade indicated. Accomplish final grading after the pile
driving has been completed. No piles shall be driven within 6 m20 feet of concrete less than 7 days
old, unless so directed. Carefully locate piles to the lines and spacing shown and drive them to either
the plumb position or the batter indicated.
c. Limit dynamic driving stresses to the crushing strength of the timber. If the pile encounters a
sudden high driving resistance, cease driving and immediately notify the Contracting Officer and proceed
as directed. If during driving, the pile encounters a sudden decrease in penetration resistance, investigate
the cause; unless a satisfactory reason is found and the pile is undamaged, reject the pile and replace
it without additional cost to the Government.
d. Take care to operate the hammer at its short stroke when the tip of the pile encounters soft material
of little resistance either at the start of the driving or in passing into poor subsoil. The hammer
should continue at its short stroke until sufficient resistance is built up to prevent damage due to
tensile wave stresses. When driving is interrupted before final penetration is reached, the record of
the penetration shall not be taken until after at least a 305 mm 12 inches penetration has been accomplished
on the resumption of driving. Minimum penetration of the tops of wood piles being used in composite
piles shall be 600 mm 2 feet below the low water table.
e. The length of the metal shell may vary according to requirements for proper seating of the piles,
elevations of groundwater, and the required pile cut-off. Where piles longer than the specified length
measured from point to cut-off elevations are required to provide specific bearing capacities, provide
the longer piles by furnishing longer wood sections as directed. As an option, provide longer piles
by increasing the lengths of concrete sections, but only after approval. Upon approval, where the specified
bearing capacities are obtained with piles of less than the specified lengths, shorter piles may be used,
but the tops of wood sections shall be driven at least 600 mm 2 feet below the water table.
3.1.1 Concrete Placement
Use an approved method for placing concrete in the shells. Place the concrete in a continuous flow from joint
to top of piles. However, no concrete shall be placed in any shell until all other piles within a radius of
6 m 20 feet [or heave range] have been driven. Shells shall be free of deformations and water. Place concrete
by tremie and not dropped through water.
3.1.2 Splices
Unless otherwise directed, construct field splices as indicated. Splices shall maintain the true alignment and
position of the pile sections and develop the full strength of the pile in both bearing and bending. Proprietary
prefabricated splicer sleeves may be used upon approval.
3.1.3 Tolerances in Driving
NOTE: Foundation piles should not be more than 75 to 150 mm (3 to 6 inches)
from their intended plan position.
Top of any pile at elevation of cutoff shall be within [_____] mm inches of the planar location indicated. Manipulation
of piles to force them into position will not be permitted. Check piles for heave and redrive those found to
have heaved to the required tip elevation. Piles damaged or driven outside the above tolerances shall be replaced,
or additional piles driven at locations specified by the Contracting Officer at no expense to the Government.
3.1.4 Cutting of Piles
Cut off piles at the elevations indicated by an approved method; remove surplus material from the job site.
3.1.5 Rejected Piles
Withdraw piles damaged, mislocated, or driven out of alignment beyond the maximum tolerances and replace them
with new piles; or cut off and abandon them. Additional piles shall be driven as directed; excess cut off from
piles and unacceptable piles shall be removed from the site of work. Perform all work, in connection with withdrawing
and removing from the site rejected piles; without additional cost to the Government.
3.1.6 Predrilling
NOTE: Predrilling is normally terminated at a depth equal to two thirds of
the total length of the pile embedment.
Predrilling will be permitted only when approved. The hole shall be [_____] mm inches less in diameter than
the diagonal dimension of the pile. All predrilled piles shall be seated by final driving to provide the required
pile capacities.
3.1.7 Collars or Bands
Use collars or bands of an approved design where required for the protection of the top of piles against splitting,
brooming, and other damage when the piles are being driven.
3.1.8 Metal Shoes
Where indicated or directed, securely attach metal shoes of an approved design to the piles in a manner described
in the detail drawings.
3.1.9 Joints
Joints between the wood and concrete sections shall be as indicated in the detail drawings.
3.1.10 Welding
Conform all field welding, and preparation of materials for welding, to AWS D1.1/D1.1M or AWS D1.4/D1.4M, as
appropriate, using proper materials and experienced personnel whose ability and qualifications to do acceptable
work have been fully demonstrated.
3.1.11 Pile Heave
When large pile clusters or piles are driven with very close spacing, take periodic elevations on the tops of
all piles to observe and determine pile heave. Such elevations shall be taken on a telltale pipe 50 mm 2 inches
in diameter placed inside the pile shell and bearing on the top of the wood section. When such checking indicates
that pile heave has occurred and when pile driving progresses beyond effective pile heave range, all heaved piles
shall be redriven to either the original resistance or the elevation, or both, as directed. If pile heave occurs
along the shell portion of the pile, resulting in separation of the joint, the Contractor may resort to predrilling
to eliminate heave or may provide a joint of sufficient tension capacity, as authorized, without additional cost
to the Government.
3.1.12 Curing
[Maintain concrete in a moist condition for not less than 7 days for normal portland cement and for not less
than 3 days for high-early-strength cement. For each decrease of 2 degrees 5 degrees below 20 degrees C 70 degrees
F in the average curing temperature, these curing periods shall be increased by 4 days for units of normal portland
cement and by 2 days for units of high-early-strength cement.] [Curing shall be in accordance with Section
03 31 00.00 10 CAST-IN-PLACE STRUCTURAL CONCRETE.]
3.1.13 Long Piles
Piles having a slenderness ratio greater than [22] [_____] shall be handled and driven with special precautions
to ensure against overstress or leading from a plumb or true position. The slenderness ratio shall be the pile
length divided by the least radius of gyration of the pile. When a high-resistance strata lying near the surface
must be penetrated, spud piles may be used only when authorized by the Contracting Officer to minimize hard driving
of long piles during the early stages of driving operations.
3.1.14 Jetting of Piles
NOTE: Jetting generally should not be permitted:
a. For piles dependent on side friction in fine-grained soils (high clay or
silt content) with low-permeability where considerable time is required for
the soil to reconsolidate around the piles.
b. For piles subject to uplift or lateral forces.
c. For piles adjacent to existing structures.
d. For piles in closely spaced clusters unless the load capacity is confirmed
by test.
[Jetting of piles will not be permitted] [Jetting shall be discontinued at a depth approximately 1.5 m 5 feet
above the "calculated" tip elevation; the remaining penetration shall be achieved by driving. Before the driving
of the final 1.5 m5 feet is started, the pile shall be firmly seated in place by the application of a number
of reduced-energy hammer blows].
3.2 FIELD TEST AND INSPECTIONS
3.2.1 Test Piles
Test piles shall be of the type and shall be driven in the manner specified. The Contracting Officer will use
test pile and load test data to determine "calculated" pile tip elevations and the necessary driving resistance.
Test piles that are located within the tolerances indicated and that provide a safe design capacity as determined
by the results of a satisfactory load test may be used in the finished work. Drive test piles [at the locations
indicated] [in the vicinity of the soil boring test holes No. [_____]]. [Jetting will be authorized only when
pile testing clearly establishes the validity of its use.] Drive test piles to the tip elevation specified or
indicated. Withdraw the specified number of test piles as indicated after reaching the "calculated" tip elevation
for visual inspection of the pile.
3.2.2 Load Tests
Perform load tests, at locations shown or directed, on test piles placed to the tip elevation indicated except
as otherwise directed. Loading, testing, and recording of data shall be under the direct supervision of a registered
professional engineer, as well as the analysis of the load test data. The installation of piles shall not proceed
in a new area with substantially different subsurface conditions until a satisfactory load test has been performed
in that area and the results approved. Allow a minimum of [_____] days after submission of the test pile data
for approval. Unless otherwise directed, piles shall not be tested sooner than 3 days after driving unless sufficient
time has elapsed to allow the cast-in-place section of the pile to develop its design strength before testing.
Test loading shall conform to ASTM D 1143/D 1143M, cyclic loading method. Apply the load to the pile or pile
group by [hydraulic jacks acting against an anchored reaction frame] [hydraulic jacks acting against a weighted
platform or box] [direct loading of a weighted platform] using a spherical bearing to transmit the load to the
pile.
3.2.3 Safe Design Capacity
The safe design capacity of a test pile, as determined from the results of load tests, shall be the lesser of
the two values computed according to the following:
a. One-half of the load which causes a net settlement after rebound of not more than 0.23 mm per metric
ton 0.01 inch per ton of total test load.
b. One-half of the load which causes a gross settlement of not more than 25 mm 1 inch, provided the
load-settlement curve shows no sign of failure.
3.2.4 Inspection
The Contracting Officer may require that certain wood sections be withdrawn for test and inspection before the
shell section is added to determine the condition of the wood sections. When so required, such wood sections
shall be redriven only when approved. Withdrawn piles not suitable for redriving shall be treated as a rejected
pile as specified in paragraph PILE DRIVING. Provide a suitable light for inspecting the interiors of pile shells.
3.2.5 Pile Capacity
The capacity, as driven, of single piles not in clusters in the structure shall be not less than [_____] metric
tons tons. Determine the capacity by the following formula, modified according to the data obtained by the load
tests:
a. For single-acting hammers: R = 166.7WH/(S + 2.54 P/W) R = 2WH/(S + 0.1 P/W)
b. Double-acting hammers: R = 166.7E/(S + 2.54 P/W) R = 2E/(S + 0.1 P/W)
Where: R is the allowable static pile load in newtons pounds. W is the weight of the striking part of the hammer
in newtons pounds. H is the effective height of fall in m feet. E is the actual energy delivered by the hammer
per blow in newton-meters foot-pounds. S is the average net penetration in mm inches per blow for the last 5
blows after the pile has been driven to a depth where successive blows produce approximately equal net penetration
(a minimum distance of 1 meter 3 feet for friction piles). P is the weight of the pile in N pounds. (If P is
less than W, P/W shall be taken as unity.)