DOC

1 - Dwyer Companies

By Gordon Greene,2014-12-12 01:30
8 views 0
1 - Dwyer Companies

    Magnum Piering

    Model Prescriptive Specifications Helical Piers and Helical Anchors

    CHECKLIST FOR FOUNDATION DRAWINGS

    HELICAL PIERS AND HELICAL ANCHORS

    The following list describes items that should be included in engineering drawings

    involving helical foundations or anchors.

    ; Helical Pier and Helical Anchor Elevations, Locations, Spacing, Orientations, and

    Inclinations

    ; Bracket Assembly Type, Elevation, and Orientation

    ; Bracket Assembly Minimum Concrete Cover or Connection to Structure

    Minimum concrete cover is governed by concrete shear, punching, and reinforcing steel

    location and can be determined by typical ACI pile cap calculations. Connection of brackets to

    wood can be determined by NDS codes considering crushing, bolt bearing and shear. Due to

    the uncertainties associated with existing structures, the connection of repair Bracket

    Assemblies to existing structures can be made by the contractor. The Contractor and the

    Engineer should require each of these connections to be load tested to 1.5 times the required

    allowable load shown on the Drawings.

    ; Helical Pier and Helical Anchor Allowable Capacity

    Allowable capacity should be the allowable dead load plus live load combinations with

    building code live load reductions.

    ; All Known Public and Private Utilities

    ; Requirements for Quality Assurance Observations

    The Drawings should contain a schedule of required quality assurance observations.

    Helical Pier and Helical Anchor inspections may be part-time (10% to 30% of installations

    observed) or full-time (100% of installations observed) depending on local practice, building

    codes, and the experience level of the contractor.

    ; Maximum Plausible Bearing Capacity (Optional)

    Maximum Plausible Bearing Capacity is used to place minimum constraints on helical

    bearing plate sizing. It is important not to be overly conservative when sizing helical bearing

    plates to reduce the risk of refusal prior to the minimum length, if any.

    ; Recommended Bearing Stratum

    The Bearing Stratum should be the most stable soil or bedrock layer that is within practical

    depth limits for the project. Helical piers generally exhibit less than 1 inch of deflection at the

    allowable load in soils with a standard penetration resistance blow count greater than 15

    blows/ft. Deflections are typically less than ? inch at the allowable load when bearing directly

    on competent bedrock. When bearing in softer material with blow count less than 15 blows/ft,

    excessive deflections must be accounted for in the design. One alternative for accounting for

    excessive deflections is pre-loading. Another alternative is to use a higher factor of safety

    between ultimate and allowable load.

    ; Minimum Depth

    For axial compression, the minimum depth is the frost depth, depth to planned bearing

    stratum, depth of unknown fill, depth of the active zone in expansive soils, or depth of soft soils,

    whichever is greater, as applicable. For axial tension, the minimum depth is 5 times the

    maximum helical bearing plate diameter in clay soils, 10 times the maximum helical bearing

    plate diameter in sand soils, or the depth of the bearing stratum, whichever is greater. ; Number of Load Tests and Proof Load Tests Required (optional)

    Generally, load tests and proof load tests are not required for Magnum Helical Piers and

    Helical Anchors when capacity is verified through installation torque and a factor of safety of

    2.0 is used. If load tests are performed and installation torque is used to verify capacity, a

    factor of safety of 1.5 can be considered. In the later case, at least 2 piers/anchors should be

    tested for each pier/anchor configuration in each bearing stratum. If installation torque is not

    used to verify capacity, then at least 10% of all anchors/piers should be load tested, and a

    factor of safety of 3.0 should be considered.

    31 66 15-1

    Revised 9/5/07 ; Copyright 2007 Magnum Piering, Inc. All Rights Reserved.

    Magnum Piering

    Model Prescriptive Specifications Helical Piers and Helical Anchors

; Allowable Deflection for Load Testing (optional)

    ; Locations of Load Tests and Proof Load Tests (optional)

    ; Post Tensioning of Helical Anchors (optional)

    Post tensioning is used to reduce deflection by pre-loading a structure. It is beneficial for

    designing earth retention structures and can reduce the required flexural strength of a wall

    facing.

    ; Requirements for Design Calculations (optional)

    If desired, the Engineer can request design calculations for the supplied helical anchor or

    helical pier system. This is sometimes useful when downdrag, buckling, lateral loading,

    corrosion or other items are a concern.

    ; Number and Size of Helical Bearing Plates (optional)

    In most cases, the number and size of helical bearing plates will be determined by the

    contractor. If desired, the Engineer can specify a combination of helical bearing plates based

    on experience or individual bearing calculations. An example would be specifying a single

    helical bearing plate if the helical pier is to bottom on hard bedrock rather than in the

    overburden.

    ; Maximum Length (optional)

    A maximum length is specified to prevent the contractor from generating excessive fees

    for helical pier or anchor installation using too few or undersized helical bearing plates. It is

    also used in cases where helical piers are to be supported in a stronger upper bearing stratum.

    For helical anchors, it may be necessary to specify a maximum length due to property line or

    right-of-way geometric site restrictions.

    ; Planned Length (optional)

    The planned length is specified when the Contract payment is based on unit length so that

    all Contractors bid the same length. A planned length specification is not necessary when

    payment terms will be based upon a per unit basis where one unit is a Helical Pier or Helical

    Anchor. In order to ensure similar bids, planned length might be used with a planned helical

    bearing plate configuration specification.

    ; Final Installation Torque (optional)

    Final installation torque is typically determined by the contractor using the allowable

    capacity shown on the plans and Magnum's recommended capacity to installation torque ratio.

    In some cases, the Engineer may elect to specify the final installation torque perhaps to reduce

    mathematical errors in the field or for other reasons.

    ; Special Considerations

    Helical Piers and Helical Anchors can penetrate most soil and sedimentary bedrock

    stratum provided the Standard Penetration Test blow count is less than 50 blows/6 inch

    increment. Installation of Helical Piers and Helical Anchors is difficult in soils with blow count

    greater than 50/6 inches or soils with excessive cobble, boulders, and/or large debris.

    Dual cutting edge helical bearing plates are recommended on sites with occasional cobble,

    debris, or thin layers of cemented material. Dual cutting edge (DCE) helical bearing plates are

    also recommended for projects using hand installation equipment because they tend to track

    better and require less crowd for proper installation.

    A corrosion engineer should be consulted, and special corrosion protection should be

    used in soils with resistivity below 2,000 ohm-cm, with pH below 5, with organic content above

    100 ppm, in mine or industrial waste, or other severely corrosive soils.

    31 66 15-2

    Revised 9/5/07 ; Copyright 2007 Magnum Piering, Inc. All Rights Reserved.

Magnum Piering

    Model Prescriptive Specifications Helical Piers and Helical Anchors

    SECTION 31 66 15

    HELICAL PIERS AND HELICAL ANCHORS

PART 1 GENERAL

1.01 Description

    This work pertains to furnishing and installing Helical Piers, Helical Anchors, and Bracket Assemblies shown in the Contract in accordance with the Drawings and this specification. Each Helical Pier and Helical Anchor shall be installed at the location and to the elevation, minimum length, and installation torque indicative of the allowable capacities shown on the Plans or as established. Helical Piers and Helical Anchors shall be load tested if required on the Drawings. Helical Anchors shall be post-tensioned if specified.

1.02 Related Work

Section 31 23 33 Trenching, Backfilling and Compacting

    Section 31 23 00 Excavation and Fill

1.03 Referenced Codes and Standards

    This specification is based on nationally recognized codes and standards including the references listed below. In case of a conflict between the reference and this specification, this specification shall govern.

A. American Society for Testing and Materials (ASTM):

    1. ASTM A36/A36M Structural Steel

    2. ASTM A123-02 Standard Specification for Zinc (Hot-Dip Galvanized)

    Coatings on Iron and Steel Products

    3. ASTM A153-05 Standard Specification for Zinc Coating (Hot Dip) on Iron

    and Steel Hardware

    4. ASTM A500 Cold-Formed Welded and Seamless Carbon Steel Structural

    Tubing in Rounds and Shapes

    5. ASTM D1143 Standard Test Method for Piles Under Static Axial

    Compressive Load

    6. ASTM D3689 Standard Test Method for Individual Piles Under Static Axial

    Tensile Load

    7. ASTM D3966-90(1995) Standard Test Method for Piles Under Lateral

    Loads

B. American Society of Mechanical Engineers (ASME):

    1. ANSI/ASME Standard B18.2.1-1996, Square and Hex Bolts and Screws,

    Inch Series

C. Occupational Safety and Health Administration (OSHA):

     1. Excavation Safety Guidelines

    31 66 15-3

    Revised 9/5/07 ; Copyright 2007 Magnum Piering, Inc. All Rights Reserved.

Magnum Piering

    Model Prescriptive Specifications Helical Piers and Helical Anchors

    1.04 Definitions

    A. Helical Pier: Manufactured galvanized steel foundation with one or more helical

    bearing plates that is rotated into the ground to support structures.

    B. Helical Anchor: Same as a Helical Pier. Term generally used when axial tension

    is the primary service load.

    C. Engineer: Individual or firm retained by Owner or General Contractor to verify

    Helical Pier and Helical Anchor quality assurance with the Contract, the

    Drawings, and this specification.

    D. Maximum Plausible Bearing Capacity: Ultimate bearing capacity of the strongest

    layer within a bearing stratum divided by a factor of safety of 2.0. When using

    field standard penetration resistance test (SPT), ultimate bearing capacity of the

    strongest layer shall be determined from the average SPT blow count plus one

    standard deviation for the population of test data within the bearing stratum.

    E. Lead Section: The first section of a Helical Pier or Helical Anchor to enter the

    ground. Lead Sections consist of a central shaft with a tapered end and one or

    more helical bearing plates affixed to the shaft.

    F. Extension Section: Helical Pier or Helical Anchor sections that follow the Lead

    Section into the ground and extend the Helical Lead to the appropriate depth.

    Extension Sections consist of a central shaft and may have helical bearing plates

    affixed to the shaft.

    G. Augering: Rotation of the shaft with little or no advancement. It can occur when

    the helical bearing plates pass from a relatively soft material into a comparatively

    hard material. Augering can also result from insufficient crowd or downward

    pressure during installation. In some cases, augering may be (temporarily)

    necessary in order to grind through an obstruction.

1.05 Qualifications

    A. Due to the special requirements for design and manufacture of Helical Piers and

    Helical Anchors, Helical Piers and Helical Anchors shall be obtained from

    Magnum Piering, Inc.

    A request to substitute any other manufactured Helical Pier and Helical Anchor

    products for use on this project must be submitted to the Engineer for review not

    less that seven (7) calendar days prior to the bid date. The request must include:

    1. A product catalog and all necessary technical data sufficient to qualify the

    proposed product substitution

    2. Evidence showing manufacturer has at least five (5) years experience in

    the design and manufacture of Helical Piers and Helical Anchors

    3. Current ICC-ES/BOCA/ICBO product evaluation report or complete

    description of product testing and manufacturing quality assurance

    programs used to assess and maintain product quality

    31 66 15-4

    Revised 9/5/07 ; Copyright 2007 Magnum Piering, Inc. All Rights Reserved.

    Magnum Piering

    Model Prescriptive Specifications Helical Piers and Helical Anchors

    B. Due to the special requirements for installation, Helical Piers, Helical Anchors, and Bracket Assemblies shall be installed by an organization specializing in the installation of Helical Piers and Helical Anchors. The Contractor shall be an authorized Magnum Piering Dealer or Installer. The Contractor shall have completed training from Magnum Piering, Inc. in the proper methods of installation of Helical Piers and Helical Anchors.

    Any Contractor desiring to bid as the Helical Pier and Helical Anchor installer for this project that is not trained and authorized by Magnum Piering, Inc., shall submit a request to the Engineer for review not less than seven (7) calendar days prior to the bid date. The request must include:

    1. A recent company brochure indicating experience in this type of work 2. Evidence of having installed Helical Piers and Helical Anchors on at least

    ten (10) projects, including project name, number and type of Helical Piers

    or Helical Anchors, project location, and client contact information 3. Resume of Contractor’s foreman including experience in the oversight of

    Helical Pier and Helical Anchor installation on at least five (5) projects in

    the last five (5) years, including project name, number and type of Helical

    Piers or Helical Anchors installed, project location, and client contact

    information

    4. List of installation and testing equipment, and a detailed description of

    proposed method of installation and load testing (if testing is required)

    C. Any installer who is not trained and authorized by Magnum Piering, Inc. or who desires to submit an alternative Helical Pier and Helical Anchor system not manufactured by Magnum Piering, Inc., must receive written approval from the Engineer prior to bidding the project. Engineer shall grant approval based on compliance with specific criteria herein. The Engineer’s decision is final.

    1.06 Submittals

    A The Contractor shall prepare and submit to the Engineer for review and approval, Shop Drawings for the Helical Piers and Helical Anchors intended for use on the project at least 14 calendar days prior to planned start of installation. The Shop Drawings shall include the following:

    1. Helical Pier and Helical Anchor product identification number(s) and

    designation(s)

    2. Maximum allowable mechanical compression and tensile strength of the

    Helical Piers and Helical Anchors

    3. Number of Helical Piers and Helical Anchors and respective design

    allowable capacities from the Drawings

    4. Planned installation depth and the number of lead and extension sections 5. Preliminary helical configuration (number and diameter of helical bearing

    plates)

    6. Manufacturer’s recommended capacity to installation torque ratio

    7. Minimum final installation torque(s)

    8. Product identification numbers and designations for all Bracket

    Assemblies and number and size of connection bolts or concrete

    reinforcing steel detail

    31 66 15-5

    Revised 9/5/07 ; Copyright 2007 Magnum Piering, Inc. All Rights Reserved.

Magnum Piering

    Model Prescriptive Specifications Helical Piers and Helical Anchors

    9. Corrosion protection coating on Helical Piers, Helical Anchors, and

    Bracket Assemblies

    B. If requested on the Drawings, the Contractor shall submit to the Engineer design

    calculations showing Helical Pier and Helical Anchor design allowable capacities.

    The design calculations shall be prepared by an independent third party hired

    and paid by the Contractor. Calculations shall include considerations for

    downdrag (if any), corrosion, expansive soils (if any), minimum installation depth,

    buckling, soil bearing and pullout capacity, and lateral resistance (if required).

    C. The Contractor shall submit to the Engineer calibration information certified by an

    independent testing agency for the torque measurement device to be used on

    the project. Calibration information shall have been obtained within the year of

    the date submitted. Calibration information shall include, but is not limited to, the

    name of the testing agency, identification number or serial number of the device

    calibrated and the date of calibration.

    D. If load tests or proof load tests are required on the Drawings, the Contractor shall

    submit for review and acceptance the proposed load testing procedure. The

    proposal shall provide the minimum following information:

    1. Type and sensitivity of load equipment

    2. Type and sensitivity of load measuring equipment

    3. Type and sensitivity of pile-head deflection equipment

    4. General description of load reaction system, including description of

    reaction anchors or bearing plate

    5. Calibration reports for equipment, including hydraulic jack, pressure

    gauges, and deflection dial gauges

    E. Magnum Piering, Inc. provides a standard one year warranty on Helical Pier, and

    Helical Anchor and Bracket Assembly products. Any additional warranty

    required from the Contractor shall be issued as an addendum to this

    specification.

    F. Work shall not begin until all the submittals have been received and approved by

    the Engineer. The Contractor shall allow the Engineer 14 days to review,

    comment, and return the submittal package. All costs associated with

    incomplete or unacceptable submittals shall be the responsibility of the

    Contractor.

1.07 Shipping, Storage, and Handling

    A. All Helical Pier, Helical Anchor, and Bracket Assemblies shall be free of

    structural defects and protected from damage. Helical Piers, Helical Anchors,

    and Bracket Assemblies should be stored on wood pallets or supports to keep

    them from contacting the ground. Damage to materials shall be cause for

    rejection.

PART 2 PRODUCTS

2.01 Helical Piers, Helical Anchors, and Bracket Assembles

    31 66 15-6

    Revised 9/5/07 ; Copyright 2007 Magnum Piering, Inc. All Rights Reserved.

    Magnum Piering

    Model Prescriptive Specifications Helical Piers and Helical Anchors

    A. All Helical Pier, Helical Anchor, and Bracket Assemblies shall be manufactured by Magnum Piering, Inc. Unless noted otherwise, it is the Contractor’s

    responsibility to select the appropriate size and type of Helical Piers, Helical Anchors, and Bracket Assemblies to support the design allowable loads shown on the Drawings. These specifications and the Drawings provide minimum requirements to aid the Contractor in making appropriate materials selections. The size and number of helical bearing plates must be such that the Helical Piers and Helical Anchors achieve the appropriate torque and capacity in the soils at the site within the minimum and maximum length requirements. Failure to achieve proper torque and capacity shall result in Contractor replacing Helical Piers and Helical Anchors as appropriate to support the required loads. All material replacements shall be acceptable to the Engineer.

    B. All Helical Piers and Helical Anchors shall be manufactured to the following criteria:

    1. Central Shaft: 3.000 inch diameter high strength structural steel tube

    meeting the requirements of ASTM A500 Grade C. The central shaft shall

    be either 0.125 inch wall (light duty) or 0.25 inch wall (standard and heavy

    duty).

    2. Helical Bearing Plates: 8, 10, 12, or 14 inch diameter with a minimum

    thickness of 3/8 inch and meeting the requirements of ASTM A36. Helical

    bearing plates shall be attached to the central shaft via 3/8 inch fillet

    welds continuous on top and bottom and around the leading edges.

    Helical bearing plates shall be cold pressed into a near perfect helical

    shape that when affixed to the central shaft are perpendicular with the

    central shaft and of uniform pitch. The leading and trailing edges shall be

    within 3/8 inch of parallel. Average helical pitch shall be 3 inches plus or

    minus ? inch.

    3. Corrosion Protection: Helical Piers, Helical Anchors, and Bracket

    Assemblies shall be protected from corrosion by hot-dip galvanizing per

    ASTM A123 or A153, as applicable.

    4. Shaft Connections: The Helical Pier and Helical Anchor shaft connections

    shall be in-line, straight and rigid and shall have a maximum tolerable

    slack of 1/16-inch. Shaft connections shall have a flexural strength at

    least as great as the shaft itself.

    5. Bolts: Helical Pier and Helical Anchor shaft connections shall be made

    via one 7/8 inch diameter thru bolt. Bolt holes through the connection

    sleeve(s) and central shaft shall be 15/16 inch diameter. Bolts and nuts

    used to join Helical Pier and Helical Anchor sections at the shaft

    connections shall be zinc coated and either ASME SAE Grade 5 (light

    and standard duty) or ASME SAE Grade 8 (heavy duty). All Helical Pier

    and Helical Anchor bolts shall be securely snug tightened.

    6. Sleeves: Helical Pier and Helical Anchor shaft connections shall consist

    of a 3.625 inch diameter by 0.25 inch wall high strength structural steel

    tube outer sleeve meeting the requirements of ASTM A500 Grade C. The

    outer sleeve shall be welded to the central shaft via a continuous ? inch

    fillet weld all-around. Heavy duty shaft connections also shall consist of a

    2.500 inch diameter by 0.25 inch wall high strength structural steel tube

    inner sleeve meeting the requirements of ASTM A500 Grade C. The

    31 66 15-7

    Revised 9/5/07 ; Copyright 2007 Magnum Piering, Inc. All Rights Reserved.

Magnum Piering

    Model Prescriptive Specifications Helical Piers and Helical Anchors

    inner sleeve shall be welded to the central shaft via two opposing ? inch

    diameter plug welds oriented 90 degrees from and located slightly below

    the thru bolt hole.

    C. Helical Piers shall be fitted with a manufactured new construction or repair

    Bracket Assembly rated for the design allowable loads shown on the Drawings.

    Helical Anchors shall be fitted with a manufactured adjustable Bracket Assembly

    that facilitates both post-tensioning and proof load testing.

PART 3 EXECUTION

3.01 Examination

    A. Contractor shall take reasonable effort to locate all utilities and structures above

    and underground in the area of the Work. Contractor shall pot hole to determine

    the exact location of underground utilities and buried structures within three (3)

    feet of a Helical Pier or Helical Anchor installation. Contractor is responsible for

    protection of utilities and structures shown on the Drawings. Costs of avoiding,

    relocating, or repair of utilities not shown on Drawings shall be paid by Owner as

    extra work.

    B. Contractor shall review Drawings and soil borings in the Contract Documents to

    determine subsurface conditions for sizing and installation of Helical Piers and

    Helical Anchors. In addition, Contractor shall make a site visit to observe

    conditions prior to the start of Work.

    C. Contractor shall notify Engineer of any condition that would affect proper

    installation of Helical Piers and Helical Anchors immediately after the condition is

    revealed. Contractor shall halt Work until the matter can be resolved upon

    mutual satisfaction of Contractor, Owner and Engineer. Costs associated with

    construction delays, product substitutions, pier or anchor relocations, or other

    related costs resulting from an unforeseen condition, and if the result of an

    unforeseen condition could not be inferred by a reasonable Contractor from the

    Drawings and Construction Documents, shall be the responsibility of the Owner.

    D. If the number and size of helical bearing plates required for the project is not

    shown on the working drawings, the Contractor shall have the option of

    performing subsurface tests using methods subject to the review and acceptance

    of the Owner. The data collected along with other information pertinent to the

    project site shall be used to determine the required helical bearing plate

    configuration.

    E. If excavation is required for proper installation of Helical Piers and Helical

    Anchors, Contractor shall make safe excavations in accordance with OSHA

    standards. All excavations greater than 20 feet in depth or not in strict

    accordance with OSHA standard details shall be designed by a registered design

    professional specializing in the design of excavations and shoring. The costs of

    all excavations, shoring, and related design shall be born by the Contractor

    unless noted otherwise in the Contract.

    31 66 15-8

    Revised 9/5/07 ; Copyright 2007 Magnum Piering, Inc. All Rights Reserved.

Magnum Piering

    Model Prescriptive Specifications Helical Piers and Helical Anchors

    F. Contractor shall notify Engineer at least 24 hours prior to installation of Helical

    Piers or Helical Anchors to schedule quality assurance observations required on

    the Drawings.

3.02 Installation Equipment

    A. Torque Motor: Helical Piers and Helical Anchors should be installed with high

    torque, low speed torque motors, which allow the helical plates to advance with

    minimal soil disturbance. The torque motor shall be hydraulic power driven with

    clockwise and counter-clockwise rotation capability. The torque motor shall be

    adjustable with respect to revolutions per minute during installation. Percussion

    drilling equipment shall not be permitted. The torque motor shall have torque

    capacity equal to or greater than the minimum final installation torque required

    for the project. The connection between the torque motor and the installation rig

    shall have no more than two pivot hinges. The pivot hinges shall be oriented 90

    degrees from each other.

    B. Installation Equipment: The installation equipment shall be capable of applying

    adequate crowd and torque simultaneously to ensure normal advancement of

    the Helical Piers and Helical Anchors. The equipment shall be capable of

    maintaining proper alignment and position.

    C. Drive Tool: The connection between the torque motor and Helical Pier or

    Helical Anchor shall be in-line, straight, and rigid, and shall consist of a

    hexagonal, square, or round kelly bar adapter and helical shaft socket. The

    Drive Tool shall be manufactured by Magnum Piering, Inc. and shall be used in

    accordance with the manufacturers installation instructions.

    D. Connection Pin: The central shaft of the Helical Pier or Helical Anchor shall be

    attached to the drive tool by an ASME SAE Grade 8 smooth tapered pin with

    average diameter between 7/8 inch and 15/16 inch. The connection pin should

    be maintained in good condition and shall be safe to operate at all times. The

    pin should be regularly inspected for wear and deformation. The pin should be

    replaced with an identical pin when worn or damaged.

    E. Torque Indicator: A torque indicator shall be used to measure installation torque

    during installation. The torque indicator can be an integral part of the installation

    equipment or externally mounted in-line with the installation tooling. The torque

    indicator shall be capable of torque measurements with a sensitivity of 500 ft-lb

    or less. Torque indicators shall be calibrated prior to start of Work. Torque

    indicators shall be calibrated either on-site or at an appropriately equipped test

    facility. Indicators that measure torque as a function of hydraulic pressure shall

    be calibrated at normal operating temperatures. Torque indicators shall be re-

    calibrated if, in the opinion of the Engineer, reasonable doubt exists as to the

    accuracy of the torque measurements.

    31 66 15-9

    Revised 9/5/07 ; Copyright 2007 Magnum Piering, Inc. All Rights Reserved.

Magnum Piering

    Model Prescriptive Specifications Helical Piers and Helical Anchors

    3.03 Installation Procedures

    A. Unless shown on the Drawings, the number and size of helical bearing plates

    shall be determined by the Contractor in order to achieve the required torque and

    tensile/bearing capacity for the soil conditions at the site. However, the ratio of

    design allowable capacity to the total area of the helical bearing plates shall not

    exceed the Maximum Plausible Bearing Capacity of the bearing stratum.

    B. Connect the lead section to the Torque Motor using the Drive Tool and

    Connection Pin. Position and align the Lead Section at the location and to the

    inclination shown on the Drawings. Advance the Lead Section and continue to

    add Extension Sections to achieve the Termination Criteria. All sections shall be

    advanced into the soil in a smooth, continuous manner at a rate of rotation not to

    exceed 30 revolutions per minute. Snug tight all coupling bolts.

    C. Constant axial force (crowd) shall be applied while rotating Helical Piers or

    Helical Anchors into the ground. The crowd applied shall be sufficient to ensure

    that the Helical Pier or Helical Anchor advances into the ground a distance equal

    to at least 80% of the blade pitch per revolution during normal advancement.

    D. The torsional strength rating of the Helical Pier or Helical Anchor shall not be

    exceeded during installation. For Magnum Piering products, the torsional

    strength ratings are listed below.

    1. Light Duty 4,000 ft-lbs

    2. Standard Duty 8,000 ft-lbs

    3. Heavy Duty 12,500 ft-lbs

    E. Bolt hole elongation due to torsion of the shaft of a Helical Anchor at the drive

    tool shall be limited to ? inch. Helical Anchors with bolt hole damage exceeding

    this criterion shall be cause for rejection.

    F. When the Termination Criteria of a Helical Pier or Helical Anchor is obtained, the

    Contractor shall adjust the elevation of the top end of the shaft to the elevation

    shown on the Drawings or as required. This adjustment may consist of cutting

    off the top of the shaft and drilling new holes to facilitate installation of Bracket

    Assemblies to the orientation shown on the Drawings. Or, installation may need

    to continue until the final elevation and orientation of the pre-drilled bolt hole is in

    alignment. The Contractor shall not reverse the direction of torque and back out

    the Helical Pier or Helical Anchor to achieve final elevation or orientation.

    G. The Contractor shall install Bracket Assemblies in accordance with Magnum

    Piering, Inc. details or as shown on the Drawings.

    H. All Helical Pier and Helical Anchor components including the shaft and Bracket

    Assembly shall be isolated from making a direct electrical contact with any

    concrete reinforcing bars or other non-galvanized metal objects because these

    contacts may alter corrosion rates.

    I. After installation, Helical Anchors shall be pre-tensioned if indicated on the

    Drawings.

    31 66 15-10

    Revised 9/5/07 ; Copyright 2007 Magnum Piering, Inc. All Rights Reserved.

Report this document

For any questions or suggestions please email
cust-service@docsford.com