HomeMy WebLinkAboutStructural/Foundation Code Compliance _ ....
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RA4C IEN BUZZARDS BAY NANTUCKET MANSFIELD
49 Herring Pond Rd 19 Old South Rd 905 S. Main St.
ENGINEERING, I N C. Buzzards Bay, MA 02532 Nantucket, MA 02554 Mansfield, MA 02048
TEL:(508)833-0070 TEL:(508)325-0044 TEL:(508)618-3029
www.BrackenEng.com FAX:(508)833-2282
February 6, 2026
Building Commissioner
Town of Yarmouth
1146 Route 28
South Yarmouth, MA 02664
Re: Structural and Foundation Code Compliance- Proposed 20' x 19.5' Carport
48 Willow Street,Yarmouth, Massachusetts
This letter certifies the structural and foundation design basis for a proposed detached, open-sided carport measuring
approximately 20.0 feet by 19.5 feet to be constructed at the residential property located at 48 Willow Street, Yarmouth,
Massachusetts.
The structure is classified as a Risk Category II accessory structure and will be supported by a spiral auger(helical)
anchor foundation system in lieu of conventional cast-in-place concrete footings.
Applicable Codes and Standards
The design and evaluation of the proposed carport and foundation system are based on the following:
• Massachusetts State Building Code(780 CMR), 10th Edition, including state amendments
• International Building Code (IBC) as adopted by 780 CMR
• ASCE/SEI 7—Minimum Design Loads and Associated Criteria for Buildings and Other Structures(as referenced
by IBC Chapter 16)
• IBC Chapter 16—Structural Loads
• IBC Chapter 18—Soils and Foundations
• ICC-ES Acceptance Criteria AC358—Helical Pile Systems and Devices
Alternative foundation systems are permitted under 780 CMR§104.11, provided equivalency with prescriptive code
requirements is demonstrated through recognized research and evaluation reports.
Wind Load Design—Cape Cod Coastal Exposure
The Town of Yarmouth is located on Cape Cod, an exposed coastal peninsula subject to elevated wind speeds from
hurricanes and nor'easters. In accordance with IBC Chapter 16 and 780 CMR§1611, wind loads for this project are
evaluated using ASCE 7 coastal criteria.
For this site:
• Risk Category: II (standard residential accessory structure)
• Exposure Category: C (open terrain with scattered obstructions and coastal influence)
• Basic Design Wind Speed: approximately 130-145 mph (3-second gust) per ASCE 7 wind speed maps for
Barnstable County/Cape Cod
• Wind Directionality, Height, and Exposure Factors: Applied per ASCE 7
Open-sided carports are particularly susceptible to uplift and lateral wind forces due to internal pressure equalization.
Accordingly, the foundation anchorage system is designed to resist net uplift, overturning, and sliding forces generated
under governing wind load combinations prescribed by IBC Chapter 16.
Foundation Design—IBC Chapter 18 Compliance
The spiral auger anchor foundation system functions as a deep foundation system transferring axial compression, uplift,
and lateral loads to competent soil strata, consistent with the intent of IBC Chapter 18 (Soils and Foundations).
Helical anchor systems used for this application are evaluated under ICC-ES AC358, which establishes requirements for:
• Structural and geotechnical capacity
• Axial compression and uplift resistance
• Lateral load resistance
• Installation torque correlation to verified load capacity
• Field and laboratory testing by accredited agencies
Products complying with AC358 are issued ICC-ES Evaluation Reports (ESRs) confirming compliance with the IBC and
are recognized as acceptable alternative foundation systems.
Installation is performed in accordance with the manufacturer's ESR, including minimum (48") embedment depth, spacing,
and verification of installation torque to confirm soil capacity.
Massachusetts Acceptance of Alternative Foundation Systems
Under 780 CMR§104.11, the Building Commissioner is authorized to approve alternative materials and methods of
construction when supported by valid research reports from approved sources. ICC-ES Evaluation Reports qualify as
such documentation and are routinely accepted throughout Massachusetts for helical anchor foundations.
Based on the project scale, loading conditions, and coastal wind exposure, the spiral auger anchor system provides
structural performance equivalent to or exceeding that of prescriptive concrete footing systems for this application.
Engineer's Certification
We, Bracken Engineering, Inc., hereby certify that the proposed spiral auger anchor foundation system for the 20' x
19.5' carport at 48 Willow Street, Yarmouth, Massachusetts, when installed in accordance with the applicable ICC-ES
Evaluation Report, manufacturer specifications, and the design assumptions, meets the intent and requirements of
the Massachusetts State Building Code (780 CMR), including IBC Chapter 16 (Structural Loads) and IBC Chapter
18 (Soils and Foundations).
In closing and on behalf of the property owner, we, Bracken Engineering, Inc., would like to thank you for your time and
consideration on this matter. Should you require any additional information, please contact the undersigned at either
zac@brackeneng.com or 508-833-0070
Sincerely,
BRACKEN ENGINEERING, INC. .T
TAChAR Y L.
a ry L. Basinski, PE, CFM ,.f. \ N .477 7
D ector of Operations »�`-.
ES
www.icc-es.org I (800) 423-6587 I (562) 699-0543 A Subsidiary of the International Code Council®
ACCEPTANCE CRITERIA FOR
HELICAL PILE SYSTEMS AND DEVICES
AC358 (24)
Published April 2025
PREFACE
Evaluation reports issued by ICC Evaluation Service,LLC(ICC-ES),are based upon performance features of the International family
of codes,and may include other codes,as applicable.
For alternative materials,design and methods of construction and equipment,see Section 104.2.3 of the 2024 International Building
Code®(IBC),Section R104.2.2 of the 2024 International Residential Code®(IRC),Section 104.11 of the 2021 IBC and earlier editions,
and Section R104.11 of the 2021 IRC and earlier editions.
This acceptance criteria has been issued to provide interested parties with guidelines for demonstrating compliance with
performance features of the codes referenced in the criteria. The criteria was developed through a transparent process involving
public hearings of the ICC-ES Evaluation Committee,and/or on-line postings where public comment was solicited.
Acceptance criteria will have a "published" date, which is the date the document was approved by the Evaluation Committee,
whether new or revised.The number in parenthesis following the AC number is the year of the newest referenced code edition.After
the newest reference code edition,an"a"denotes first revision,"b"denotes 2nd revision and so on.When existing acceptance criteria
are revised with a compliance date or major overhaul,a new"Edition"will be shown after the referenced code edition number.When
applicable,the compliance date is the date by which relevant evaluation reports must comply with the requirements of the criteria.
See the ICC-ES web site for more information on compliance dates.
If this criteria is a revised edition, a solid vertical line (I) in the margin within the criteria indicates a change from the previous
edition.A deletion indicator(-,)is provided in the margin where any significant wording has been deleted.
ICC-ES may consider alternate criteria for report approval, provided the report applicant submits data demonstrating that the
alternate criteria are at least equivalent to the criteria set forth in this document, and otherwise demonstrate compliance with the
performance features of the codes.ICC-ES retains the right to refuse to issue or renew any evaluation report,if the applicable product,
material, or method of construction is such that either unusual care with its installation or use must be exercised for satisfactory
performance,or if malfunctioning is apt to cause injury or unreasonable damage.
Acceptance criteria are developed for use solely by ICC-ES for purposes of issuing ICC-ES evaluation reports.
ICC EVALUATION SERVICE®and ICC-ES®(and their associated logos)are registered trademarks and service marks of ICC Evaluation
Service,LLC,and INTERNATIONAL CODE COUNCIL®,ICC®,INTERNATIONAL BUILDING CODE®and IBC®(and their associated logos)
are registered trademarks and service marks of its parent company, International Code Council,Inc.
No portion of this document(AC358)may be copied,reproduced,reprinted,republished,distributed,transmitted,or modified in any form or
manner without the express prior written permission of ICC-ES. Any request for such permission should be addressed to ICC-ES at 3060
Saturn Street,Suite 100,Brea,California 92821. Any of the foregoing expressly authorized by ICC-ES must include all the copyright,
trademark,service mark and other proprietary rights notices contained herein.
Copyright°2025 ICC Evaluation Service, LLC. All rights reserved.
REVISIONS TO THE ACCEPTANCE CRITERIA FOR
HELICAL PILE SYSTEMS AND DEVICES (AC358)
1.0 INTRODUCTION 1.3.3 ANSI/AWC NDS,National Design Specification
1.1 Purpose:The purpose of this acceptance criteria is for Wood Construction (NDS), American Forest & Paper
Association.
to establish requirements for helical pile systems and
helical pile devices to be evaluated in ICC Evaluation 1.3.4 ACI 318, Building Code Requirements for
Service, LLC (ICC-ES), evaluation reports under the 2024, Structural Concrete,American Concrete Institute.
2021, 2018, 2015, 2012, 2009 and 2006 International 1.3.5 AISC 360, Specification for Structural Steel
Building Codes (IBC). The basis for evaluation is 2024, Buildings,American Institute of Steel Construction.
2021, 2018, 2015, 2012 and 2009 IBC Section
1810.3.3.1.9,and 2006 IBC Section 104.11. 1.3.6 AISC 341, Seismic Provisions for Structural
Steel Buildings,American Institute of Steel Construction.
The reason for the development of this acceptance
criteria is to supplement general requirements for helical 1.3.7 ANSI/ASME Standard B18.2.1-2012 (R2021),
piles in the IBC to permit evaluation of helical pile systems Square and Hex Bolts and Screws, Inch Series, American
and devices. Society of Mechanical Engineers.
The purpose of Appendix A of this criteria is to establish 1.3.8 ANSI/AWS D1.1/D1.1M, Structural Welding
requirements for helical pile systems and devices to be Code-Steel (AWS D1.1/D1.1M), American Welding
ie
evaluated in ICC Evaluation Service, LLC (ICC-ES), Society.
I evaluation reports under the 2024,2021,2018,2015,2012, 1.3.9 ASTM A123-17,Standard Specification for Zinc
2009 and 2006 International Residential Codes(IRC). (Hot-Dip Galvanized)Coatings on Iron and Steel Products,
1.2 Scope: This criteria provides methods to establish ASTM International.
the allowable loads and deformation capacities of helical 1.3.10 ASTM A153-16A, Standard Specification for
pile systems and devices used to resist axial compression, Zinc Coating (Hot-Dip)on Iron and Steel Hardware,ASTM
axial tension or lateral loads.This criteria applies to helical International.
pile systems and devices defined in Section 1.4 and 2024 1.3.11 ASTM B633-23 Standard Specification for
IBC Chapter 2 for use under 2024,2021,2018,2015,2012 Electro deposited Coatings of Zinc on Iron and Steel,ASTM
and 2009 IBC Section 1802. This criteria includes International.
provisions for determining soil embedment and soil
capacity. 1.3.12 ASTM B695-21 Standard Specification for
Coatings of Zinc Mechanically Deposited on Iron and Steel,
This criteria is limited to helical pile systems and devices ASTM International.
used under the following conditions:
1.3.13 ASTM C31-21a, Standard Practice for Making
1.2.1 Structures assigned to Seismic Design and Curing Concrete Test Specimens in the Field, ASTM
Categories (SDCs) A, B and C only, unless additional International.
requirements in Section 3.14 of this criteria are satisfied for
use in structures assigned to SDCs D through F in 1.3.14 ASTM C39-23, Standard Test Method for
accordance with the IBC. Compressive Strength of Cylindrical Concrete Specimens,
ASTM International.
1.2.2 Exposure conditions to soil that are not
indicative of potential pile deterioration or corrosion 1.3.15 ASTM D1143-20, Standard Test Methods for
situations. Deep Foundation Elements Under Static Axial
Compressive Load,ASTM International.
Use of helical pile systems and devices in exposure 1.3.16 ASTM D1586-18E1, Standard Test Method for
conditions that are indicative of potential pile deterioration Standard Penetration Test(SPT)and Split-Barrel Sampling
or corrosion situations as defined by the following: (1) soil of Soils,ASTM International.
resistivity less than 1,000 ohm-cm;(2)soil pH less than 5.5;
(3) soils with high organic content; (4) soil sulfate 1.3.17 ASTM D3689-22, Standard Test Methods for
concentrations greater than 1,000 ppm; (5)soils located in Deep Foundations under Static Axial Tensile Load, ASTM
landfills,or(6)soil containing mine waste, is beyond scope International.
of this criteria. 1.3.18 ASTM D3966-22, Standard Test Methods for
1.2.3 Helical products manufactured from carbon Deep Foundation Elements under Static Lateral Loads,
steel,with optional zinc or powder coatings. ASTM International.
1.3 Codes and Referenced Standards: Where 1.3.19 ICC-ES Acceptance Criteria for Corrosion
standards are referenced in this criteria, these standards Protection of Steel Foundation Systems Using Polymer
shall be applied consistently with the code(IBC)upon which (EAA)Coatings(AC228).
compliance is based in accordance with Table 1. 1.3.20 ISO 21930-2017,Sustainability in Buildings and
1.3.1 2024,2021, 2018,2015,2012,2009,and 2006 Civil Engineering Works - Core Rules for Environmental
International Building Code® (IBC), International Code Product Declarations of Construction Products and
Council. Services, International Organization for Standardization
1.3.2 ICC-ES Acceptance Criteria for Inspection (ISO).
Agencies(AC304). 1.3.21 ISO 21930-2017 Sustainability in Buildings and
Civil Engineering Works - Core Rules for Environmental
Product Declarations of Construction Products and
Page 2 cf 24
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358)
Services, International Organization for Standardization 5.2. All material specifications shall comply with ASTM,
(ISO). ACI,NDS,AISC,or IBC(2024,2021,2018,2015,2012 and
1.4 Definitions: Terminology herein is based on the 2009 IBC Section 1810.3.2.3) requirements. Material
Glossary of the IBC,AISC and the following definitions: composition, grade, and sizes of bolts and fasteners shall
be based on criteria in AISC,ASTM,or ANSI requirements.
1.4.1 Angle Bracket: A side load bracket with
horizontal bearing plate extending below and supporting a 2.1.3 Installation Instructions: Procedures and
concrete foundation. details regarding helical pile system and device installation,
including product-specific requirements, exclusions,
1.4.2 Helical Pile System: A factory-manufactured limitations,and inspection requirements, as applicable.
steel pile designed to resist axial compression, axial
tension,and/or lateral loads from structures,consisting of a 2.1.4 Packaging and Identification:A description of
helical pile having a central shaft with one or more helical- the method of packaging and field identification of each
shaped bearing plates, extension shafts, couplings and a helical pile system and device. The product identification
bracket that allow for attachment to structures.The piles are shall be in accordance with the product identification
screwed into the ground by application of torsion and provisions of the ICC-ES Rules of Procedure for Evaluation
extended until a desired depth or a suitable soil or bedrock Reports. Identification provisions shall include the
bearing stratum is reached. manufacturer's name and address, product name and
model number, evaluation report number.
1.4.3 Helical Pile Device: For purposes of this
criteria, a helical pile device is any part or component of a 2.1.5 Design Calculations: Clear and
helical pile system. comprehensive calculations of ASD or LRFD structural
capacities for system or device, based on requirements of
1.4.4 Lateral Resistance: Capacity of a helical pile the IBC and this criteria. Calculations shall be signed and
system or device to resist forces acting in a direction that is sealed by a registered design professional.
perpendicular to the longitudinal direction of the shaft.
2.2 Testing Laboratories: Testing laboratories shall
1.4.5 Conventional Design: Methods for comply with Section 2.0 of the ICC-ES Acceptance Criteria
determining design capacities of the helical pile system that for Test Reports (AC85) and Section 4.2 of the ICC-ES
are prescribed by and strictly in accordance with standards Rules of Procedure for Evaluation Reports.
and codes referenced in Section 1.3.
2.3 Test Reports: Reports of tests required under
1.4.6 Special Analysis: Methods for determining Section 3.0 of this criteria shall comply with AC85 and
design capacities of the helical pile system that incorporate reporting requirements in referenced standards.
finite element modeling, discrete element modeling, strain 2.4 Product Sampling: Sampling of devices for tests
compatibility, or other conventional analytical/numerical
techniques. Computer software developed for the analysis under this criteria shall comply with Section 3.1 of AC85.
of laterally loaded helical piles, which incorporate methods 2.5 Qualification Test Plan: A qualification test plan
of analysis considering the nonlinear interaction of the shaft shall be submitted to and approved by ICC-ES staff prior to
with soil, is an example of special analysis. any testing being conducted.
1.4.7 Shaft Flexural Length: The length of the shaft 3.0 DESIGN, TEST, AND PERFORMANCE
determined by special analysis, measured from the top of REQUIREMENTS
embedded shaft (typically at ground level) downward into 3.1 General:The helical pile systems and devices shall
the soil to the first point of zero lateral deflection, for the be evaluated for resistance to axial compression, axial
shaft subjected to the allowable lateral load of the helical tension, or lateral loads, or a combination of these loads.
pile systems and helical pile devices. The required capacities shall be evaluated by considering
1.4.8 Shaft Seismic Flexural Length: The length of four primary structural elements of the helical pile system
the shaft equal to 120 percent of the shaft flexural length. as shown in Figures 1 through 4. These elements are
2.0 BASIC INFORMATION described as Bracket Capacity (P1), Shaft Capacity (P2),
Helix Capacity(P3), and Soil Capacity(P4). The allowable
2.1 General: The following information shall be capacity of a helical pile system or device shall be the
submitted with ICC-ES evaluation report applications: lowest value of P1, P2, P3, and P4, from each application
2.1.1 Summary Document: A tabulated list of the illustrated in Figures 1 through 4. For evaluation of helical
helical pile systems, devices, and combinations thereof to pile devices subject to combined lateral loads and axial
be included in the ICC-ES evaluation report, along with compression or axial tension,the allowable lateral capacity
proposed structural capacities. All systems and devices and allowable axial capacity shall be determined and
shall be clearly identified in the documentation with distinct reported separately. The allowable strength under
product names and/or product numbering. combined load conditions shall be determined using the
interaction equation provided in the AISC referenced
2.1.2 Product Description: Helical pile products standard.
shall be manufactured from carbon steel,with optional zinc 3.2 P1 Bracket Capacity: The P1 bracket capacity is
or powder coatings. Complete information pertaining to the the maximum load that can be sustained by the bracket
helical pile systems or devices, including material device of a helical pile system based on strength in
specifications and drawings showing all dimensions and accordance with Section 3.10.
tolerances,and the manufacturing processes.All materials,
welding processes and manufacturing procedures used in 3.3 P2 Shaft Capacity: The P2 shaft capacity is the
helical pile systems and devices shall be specified and specified load that can be sustained by the shaft or coupling
described in quality documentation complying with Section
Page 3 of 24
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358) '
elements of a helical pile device based on strength in P' = 0.74)Pn(LRFD) (Eq-4)
accordance with Section 3.11. 3.7.2 Special Analysis: Where special analysis is
3.4 P3 Helix Capacity: The P3 helix capacity is the used, the allowable capacity P'shall be taken as the least
specified load that can be sustained by the helix element of of 0.6 times the resistance based on yield strength(Py)and,
a helical pile device based on strength or deformation in 0.5 times the resistance based on maximum strength(Pmax)
accordance with Section 3.12. (Eq-5). The tested allowable capacity shall be greater than
3.5 P4 Soil Capacity: The P4 soil capacity for axial or equal to the calculated allowable capacity determined in
loading is the least allowable axial load that can be Eq-5.
sustained by the soil or bedrock bearing stratum supporting P'=0.6Py and 0.5Pmax (Special analysis) (Eq-5)
the helical pile, as determined by a registered design
professional based on site-specific conditions in 3.7.3 Direct Measurement: Where load testing only
accordance with Items 1 and 3 of 2024, 2021, 2018,2015, is used and the number of samples is not specified, the
2012 and 2009 IBC Section 1810.3.3.1.9 and through allowable capacity shall be reported as the average
installation torque correlations in accordance with Item 2 of allowable strength determined in accordance with Section
2024, 2021, 2018, 2015, 2012 and 2009 IBC Section 4.0 from tests conducted on at least five specimens,
1810.3.3.1.9 and Section 3.13.1 of this criteria.See Section provided all test results are within 15 percent (15%)of the
3.6 for the P4 soil capacity for lateral loading. average. Otherwise, the allowable capacity from testing
only shall be based on the least test result. For direct
3.6 Determination of Allowable Design Capacities: measurement of helical pile device capacities,testing shall
In accordance with Section 3.7, the allowable design be conducted in accordance with the applicable test
capacities of helical pile elements P1 and P2 shall be procedure described in Section 4.0.The allowable capacity,
evaluated based on Conventional Design with no testing P,'shall be taken as 0.6 times the resistance based on yield
required, Special Analysis with verification tests, or solely strength (Py) or 0.5 times the maximum strength (Pmax),
on tests. For Type A brackets allowable design capacities whichever yields the lowest value(Eq-6). In the case when
shall be based on either conventional design or direct the yield strength is not well defined, P'shall be taken as
measurement only. All load tests shall be conducted in 0.5 times Pmax. When establishing the allowable load of a
accordance with Section 4.0. The allowable capacity P3 Type A bracket through direct measurement in accordance
shall be determined through load testing only as prescribed with Section 4.1.1 or a helical plate when tested in
in Section 3.12. The allowable axial capacity P4 shall be accordance with Section 4.3, the allowable load shall be
determined by registered design professional, based on permitted to be determined using the maximum strength.
site-specific conditions as indicated in Items 1 and 3 of
'
2024, 2021, 2018, 2015, 2012 and 2009 IBC Section P =lesser of(0.6Py or 0.5Pmax)
1810.3.3.1.9 and through installation torque correlations as (Direct Measurement) (Eq-6)
specified in Item 2 of 2024, 2021, 2018, 2015, 2012 and
2009 IBC Section 1810.3.3.1.9 and Section 3.13.1 of this For direct measurement of soil capacity, testing shall
criteria. The allowable lateral load capacity, P4, shall be be conducted in accordance with Sections 4.4.1.2 and
determined by a registered design professional or by lateral 4.4.2.2. For determination of allowable soil capacity, a
load testing in accordance with Section 3.13.2. factor of safety equal to 2 or greater shall be applied to the
maximum measured soil capacity.
3.7 Design Methods:
3.8 RESERVED FOR FUTURE PROVISIONS
3.7.1 Conventional Design: For conventional
design of steel, either Allowable Stress Design (ASD) or 3.9 Corrosion: Helical pile systems and devices shall
Load and Resistance Factor Design (LRFD) methods be bare steel, powder-coated steel or zinc-coated steel.
referenced in the IBC may be used to calculate the Powder coatings shall comply with the ICC-ES Acceptance
allowable design capacity, P'. The allowable stresses for Criteria for Corrosion Protection of Steel Foundation
structural steel in compression and in tension should not Systems Using Polymer (EAA) Coatings (AC228) except
exceed 0.6Fy and 0.5F„ in accordance with Table the coating thickness shall be at least 450 pm(0.018 inch).
1810.3.2.6 of the 2024, 2021, 2018, 2015, 2012 and 2009 Zinc coatings shall comply with ASTM A123, A153, B633,
IBC. For design of concrete, strength design methods or B695, as applicable. Loss in steel thickness due to
referenced in ACI 318 (IBC) shall be used to calculate the corrosion shall be accounted for in determining structural
design capacity. capacities by reducing the thickness of all helical pile
components by the sacrificial thickness over a period, t, of
3.7.1.1 ASD Method: When using the ASD 50 years. The design thickness, Td, of helical pile
method,the allowable design capacity,P',shall be taken as components used in capacity calculations and testing shall
the allowable strength, Pa, and shall be determined in be computed by Eq.-7. For purposes of design calculations
accordance with the applicable code or referenced and fabrication of test specimens, the thickness of each
standard(Eq-3). component shall be reduced by 1/2 Ts on each side, for a
P'= Pa (ASD) (Eq-3) net reduction in thickness of Ts.
3.7.1.2 LRFD Method: When using the LRFD or Td = Tn— TS (Eq-7)
strength design method, and ASD provisions are not where T„ is either the design wall thickness for HSS, as
contained in the code-referenced standards, such as ACI prescribed in AISC 360, Section B4.2, if applicable, or
318,the allowable design capacity,P',shall be taken as 0.7 nominal thickness and Ts is sacrificial thickness(t=50 yrs).
times the design strength, coP,,,where rpP„is determined in
accordance with the applicable code or referenced Td<base steel thickness
standard (Eq-4). Zinc-coated steel: Ts=25 0-65=318 pm (0.013 in)
Page 4 of 24
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358)
Bare steel, Ts=40 0-80=915 pm (0.036 in) incorporating a lateral component of forces in the analysis
Powder coated steel: of the bracket, helical pile shaft, and bracket connections.
The pile or extension shaft shall be attached to the bracket
Ts =40(t—16)0•80 = 671µm(0.026 in) by a mechanical connection. Installation shall be limited to
For bare steel and powder-coated steel, T„shall be the support of uncracked concrete, as determined in
base-steel thickness (base-steel design wall thickness for accordance with the applicable code. In order for the shaft
Section B4.2 of AISC 360, if applicable). For zinc-coated to be considered side-sway braced, the structure shall
steel, T„may be the sum of the base-steel thickness(base- provide lateral restraint to the shaft equal to or greater than
steel design wall thickness for Section B4.2 of AISC 360, if 0.4 percent of the shaft's allowable axial compression load.
applicable) and specified minimum average zinc coating 3.10.1 Type A Side Load: Type A brackets are
thickness. For zinc coated thickness equal to or greater illustrated in Figure 1 and used to support tensile or
than 86 pm(0.0034 in),the sacrificial thickness, Ts,shall be compressive loads that are not concentric with the primary
318 pm (0.013 in). For zinc coating thickness less than 86 axis of the helical pile shaft. Type A brackets shall only be
pm (0.0034 in), Ts, shall be determined by linear used to support structures that are braced as defined in
interpolation between bare steel and zinc coated steel using 2024, 2021, 2018, 2015, 2012 and 2009 IBC Section
the actual specified zinc coating thickness. 1810.2.2 and 2006 IBC Section 1808.2.5. Use of Type A
For powder-coated steel, the life of powder coating is brackets for supporting lateral loads is permitted, provided
taken as 16 years maximum.Hence,t has been reduced by that the lateral load capacities of the brackets are designed
16 in the determination of T. by a registered design professional in accordance with IBC
Chapter 18. Rotational moments caused by load
For verification of Special Analysis or for determination of eccentricity shall be subdivided into two components,
allowable capacity through testing only, test specimens bracket eccentricity and structure eccentricity,as illustrated
shall be constructed using steel thickness equal to Td. in Figure 5. The shaft and the connected bracket
Alternatively, unaltered test specimens may be used, and components, consisting of the connected bracket,
the resulting allowable strength shall be reduced by connection of the bracket to the shaft,and connection of the
multiplying the result by a scaling factor that takes into bracket to the structure, shall resist bracket eccentricity.
account corrosion and the observed failure mode. Thus, a Structure eccentricity varies with application and is
tension failure result shall be scaled by the area of the generally resisted by the internal strength of the structure to
fracture surface,while a flexural failure would be scaled by which the bracket is attached. Therefore, resistance to
the reduced section modulus. The testing laboratory shall structure eccentricity shall be determined on a case-by-
determine the appropriate scaling method and identify the case basis. For purposes of bracket eccentricity and
failure mode. internal strength design,the location of the resultant vertical
Corrosion loss shall be accounted for regardless of compression force of the concrete structure on an angle
bracket shall be taken as the centroid of an area defined by
whether devices are below or above ground or embedded
in concrete. Zinc-coated steel and bare steel components the uniform concrete bearing stress, taken as 0.35f� for
shall not be combined in the same system, except where ASD and 0.55Pc for LRFD as shown in Figure 5. The
the sacrificial thickness, T5,for the zinc-coated components strength of connected bracket components, shafts shall be
is taken as that given for bare steel components(0.036 inch evaluated based on one of two methods of proportioning
moment between helical pile shaft and connected bracket
or 915 pm). Powder coated steel may be combined with components.The first method is based on allowable stress
zinc-coated steel and bare steel components.All helical pile design and is described in Section 3.10.1.1. The second
components shall be galvanically isolated from concrete method is based on limit state analysis and is described in
reinforcing steel,building structural steel,or any other metal Section 3.10.1.2.
building components.
3.10.1.1 Allowable Stress Design: This method of
3.10 P1 Bracket Capacity: Helical pile brackets shall be evaluation assumes the resistance to overturning moment
classified as one of four types:side vertical load,direct load, is proportioned between the helical pile shaft and the
slab support compressive load and tension anchor load. connected bracket components based on relative stiffness.
These types of brackets are illustrated in Figures 1 through The overturning moment caused by bracket eccentricity
4. Bracket capacity shall be evaluated separately for each shall be proportioned between helical pile shaft and
type. At a minimum, evaluation of P1 shall include connected bracket components using Eq-7a.
determination of strength of the connection of the bracket
to the structure, the internal strength of the bracket itself, G = Eplp/Eblb (Eq-7a)
and the strength of connection of the bracket to the helical where:
pile shaft. The frictional resistance of concrete on a
horizontal bracket component shall be determined using a 1p = Moment of inertia of helical pile or extension
coefficient of friction of 0.4 or less. The shear strength of shaft(in4 or mm4).
concrete also shall be calculated in accordance with the Ep = Modulus of elasticity of helical pile or extension
applicable code. Brackets may be evaluated for shaft(psi or MPa).
compression, tension, and/or lateral strengths, depending
on the type. The angle of the shaft with respect to the lb = Moment of inertia of connected bracket
bracket recommended by the installation instructions shall components(in4 or mm4).
be accounted for in the calculations. The evaluation shall Eb = Modulus of elasticity of connected bracket
include an allowance for a tolerance of 1 degree from the components(psi or MPa).
permissible angle of inclination. Effects of helical pile shaft
inclination relative to vertical shall be accounted for in the If G>10 Method a applies.
analysis for axial compression or axial tension loads by If G<0.1 Method b applies.
Page 5 of 24
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358)
If 0.1 <_G 510 Method c applies. where
The stiffness of the helical pile or extension shaft can Mp = Moment resistance of helical pile shaft from
be increased by reinforcing the top section of shaft with an combined axial and flexural load analysis(in—lbf
outer sleeve, T-pipe, or other means. Based on the or N-mm).
resulting value of G, the corresponding method in Sections VP = Shear in helical pile shaft at the connection to
3.10.1.1.1 to 3.10.1.1.3 shall apply the bracket or T-pipe(lbf or N).
3.10.1.1.1 Method a: Rigid Shaft:This method of
evaluation assumes the shaft and its connection to the d = 60 inches(1524 mm).
bracket are relatively rigid compared to the connection of 3.10.1.3 Connection to the Structure: Axial
the bracket to the structure. By this method, the shaft shall compression, axial tension, or lateral load connection
resist the moment due to bracket eccentricity. A free body capacities shall be determined in accordance with the IBC,
diagram of the bracket based on this method is illustrated or a current ICC-ES evaluation report. For purposes of
in Figure 5(a). The free body diagram is statically evaluation, the structure shall be modeled as a mass of
determinate. Separate evaluation of helical pile bracket structural plain concrete,semi-infinite in extent,with varying
devices by this method shall include evaluation of P2 for all strength. The structure shall be assumed to be fixed in
specified helical pile shafts to be used with the bracket. In horizontal translation and rotation, but can move freely in
the analysis of the shaft, a moment shall be applied to the the vertical direction. At a minimum, design of the
top of the shaft equal to the eccentricity of the bracket times connection shall be based on normal-weight concrete with
the axial load. a specified compressive strength of 2,500 psi(17.22 MPa),
3.10.1.1.2 Method b: Flexible Shaft:This method except as specified in Section 3.14.2. Other concrete
of evaluation assumes the helical pile shaft and/or its strengths, structural lightweight concrete, masonry and
connection to the bracket are relatively flexible compared to other materials also can be included in the evaluation at the
the connection of the bracket to structure. By this method, option of the bracket manufacturer. For all combinations of
the connection of the bracket to the structure is required to concrete strength and/or material compositions, details
resist the moment due to bracket eccentricity. Axial loads regarding connection of the bracket to the structure types
are transmitted concentrically to the helical pile shaft.A free (i.e., anchor bolt placement, grouting, surface preparation,
body diagram of the bracket based on this method is etc.)shall be prescriptively specified.
illustrated in Figure 5(b).The free body diagram is statically 3.10.2 Type B: Direct Load: Type B brackets
determinate. illustrated in Figure 2, support axial compressive or axial
3.10.1.1.3 Method c: Combined Stiffness: This tension loads that are concentric with the primary axis of the
method of evaluation assumes the shaft and the connection helical pile shaft and may be used to support lateral loads.
of the bracket to the structure are of similar stiffness. In this The strength of bracket components and connections shall
case,both the shaft and structure contribute to resisting the be evaluated in accordance with Section 3.10.2.1 or
moment due to bracket eccentricity.A free body diagram of Section 3.10.2.2 depending on whether the structure to be
the bracket based on this method is illustrated in Figure supported by the bracket is side sway braced.
5(c). The free body diagram is statically indeterminate. 3.10.2.1 Method 1: Side sway Braced: This
Numerical analysis, finite element modeling, strain method of evaluation assumes the connection of the
compatibility, or other Special Analysis shall be used to bracket to the structure provides lateral but not rotational
determine allowable capacity. Alternatively, the moment bracing for the top of the helical pile shaft so that the top of
exerted on the shaft and the connection of the bracket to the shaft is essentially a pinned connection.
the structure can be proportioned using G,and the capacity
of the bracket can be statically determined using 3.10.2.2 Method 2: Side sway Unbraced: This
Conventional Design described in Section 3.7. Evaluation method of evaluation assumes the structure provides
of P1 bracket capacity by this method shall include a neither lateral nor rotational bracing for the top of the helical
specified shaft and is necessarily coupled with evaluation of pile shaft, so that the top of the shaft is essentially a free
P2 shaft capacity. In the analysis of the shaft, a moment connection.
shall be applied to the top of the shaft equal to the 3.10.2.3 Connection to the Structure: The
eccentricity of the bracket times the appropriate proportion structures that Type B brackets are used to support may be
(G/(G+1))of axial load. concrete, steel, wood or other material. Evaluation shall
3.10.1.2 Limit State Design: This method of include specifications for connection to structures, such as
evaluation assumes at failure that the connection between material strength,embedment depth,edge distance,welds,
the bracket and structure reaches a maximum limit state bolts, bearing area, and bracing. Connection of the bracket
and the helical pile shaft has a plastic hinge. Based on to each type of structure(grade beams,walls,steel beams,
these assumptions, the rotational stability of a side load posts, etc.) for which evaluation is being sought shall be
bracket is statically determinate.The nominal load capacity detailed and analyzed separately.At a minimum, design of
of the bracket shall be determined by simultaneous solution the connection shall be based on normal weight concrete
of static equilibrium equations. In the static analysis, the with a specified compressive strength of 2,500 psi (17.22
moment at the connection of the helical pile shaft to the MPa), except as specified in Section 3.14.2. The analysis
bracket or T-pipe shall be set equal to the moment shall include considerations of internal shear and moment
resistance of the shaft based on combined axial and flexural within concrete elements, as applicable. Analysis of wood,
loading.The shear at the connection of the helical pile shaft steel, and concrete shall be based on the IBC, AISC 360,
to the bracket or T-pipe shall be determined by Eq-7b. AWC NDS, or ACI 318,as applicable.
Vp = Mp/d (Eq-7b) 3.10.3 Type C: Slab Support: Type C brackets
support concrete flatwork. These brackets shall support
Page 6 of 24
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358)
axial compression loads concentrically. Use of Type C the top of the shaft in buckling calculations in accordance
brackets for supporting tension or lateral loads is outside with Section 3.10 and Section 3.11.2.3.
the scope of this criteria. Calculations shall be performed 3.11.2.1 Unsupported Length: Unsupported shaft
proving whether the bracket can be considered sideways lengths shall include the length of the shaft in air,water, or
braced.Evaluation shall comply with Section 3.10.2.1 of the in fluid soils.For unbraced systems,the lengths specified in
criteria for Type B direct load brackets, Method 1,and shall 2024, 2021, 2018, 2015, 2012 and 2009 IBC Section
include analysis of punching shear based on ACI 318 in 1810.2.1 shall apply unless determined otherwise by
concrete slabs of different strength and different thickness Special Analysis. In accordance with 2024, 2021, 2018,
slabs, along with recommended bracket spacing for slabs 2015,2012 and 2009 IBC Sections 1810.1.3 and 1810.2.1,
supporting 40 psf(1915 Pa) to 100 psf(4788 Pa) uniform any soil other than fluid soil shall be deemed to afford
live loads.At a minimum,evaluation shall include 4-,6-,and sufficient lateral support to prevent buckling of systems that
8-inch-thick (102, 152, and 203 mm), unreinforced slabs are braced. Bracing shall comply with 2024, 2021, 2018,
containing normal-weight concrete with minimum specified 2015,2012 and 2009 IBC Section 1810.2.2.Firm soils shall
compressive strength of 2,500 psi (17.22 MPa). Other be defined as any soil with a Standard Penetration Test
concrete strengths and structural lightweight concrete also blow count of five or greater. Soft soils shall be defined as
can be included in the evaluation at the option of the bracket any soil with a Standard Penetration Test blow count
manufacturer. greater than zero and less than five. Fluid soils shall be
3.10.4 Type D:Tension Anchor:Type D brackets are defined as any soil with a Standard Penetration Test blow
used to support axial tension loads only. These brackets count of zero [weight of hammer (WOH) or weight of rods
shall support loads concentrically and shall not be (WOR)]. Standard Penetration Test blow count shall be
evaluated for lateral load resistance. Evaluation shall determined in accordance with ASTM D1586.
comply with Section 3.10.2 of the criteria for Type B direct 3.11.2.2 Effective Length:Effective lengths shall be
load brackets.The connection to the existing structure shall determined using the unsupported length defined in Section
be evaluated, including the range of acceptable shaft 3.11.2.1 and the appropriate effective length factor, K,
installation angles proposed by the manufacturer. determined in accordance with the AISC referenced
3.10.5 Test Requirements: Tests shall not be standard. Slenderness ratio limitations as specified by the
required for evaluation of pile brackets provided all analysis AISC referenced standards do not apply.
is accomplished using Conventional Design as set forth in 3.11.2.3 Coupling Rigidity: Coupling rigidity shall
Section 3.7.1. A minimum of three verification load tests p g g ty p g g y
be considered for all cases except braced systems in firm
shall be conducted in each load direction (axial or soft soils.To account for coupling rigidity,the eccentricity
compression, axial tension, and lateral)on any component of the axial compressive load applied to the shaft shall be
of a bracket or bracket/shaft system evaluated using increased by a distance, nxec, where n is the number of
Special Analysis. Where tests are required for verification couplings possible in the unsupported length and ec is the
of lateral resistance, tests shall be conducted to verify maximum lateral deflection of the unsupported length of
lateral resistance in all directions for which lateral shaft due to flexure of the coupling under an applied lateral
resistance is being claimed. Bracket tests shall be load of 0.4 percent of the applied axial compressive load.
conducted in accordance with Section 4.1 for compression Maximum lateral deflection of the shaft due to coupling
and tension and Section 4.4.2 for lateral resistance. flexure shall be determined in accordance with Section
3.11 P2 Shaft Capacity:At a minimum,helical pile shaft 4.2.4. In order to establish coupling rigidity, side-by-side
capacities shall be evaluated for torsion and either axial comparison tests shall be conducted on specimens with
compression, axial tension, or both. Shafts may also be and without the coupler(s). The location of the coupler(s)
evaluated for lateral resistance with consideration of shall be evenly distributed along the length of the shaft.
combined lateral and axial loading. Evaluation of shafts 3.11.3 Torsion:Shaft torsion tests shall be conducted
shall include connections between shafts. All shaft in accordance with Section 3.11.3.1 or 3.11.3.2.
connections shall be made via a mechanical coupling.
Provisions for pile splices shown in Section 1810.3.6 3.11.3.1 Torsion Test on Shaft (with Coupling)
including Section 18103.6.1 of the 2024,2021,2018,2015, Only: Torsion resistance shall be determined by testing in
2012 and 2009 IBC shall be considered in the design of the accordance with Section 4.2.2.A minimum of 12 samples,
shaft and couplers used with helical piles. with an equal number of samples from four or more
separate heats, shall be used for each shaft size and
3.11.1 Tension: Shaft evaluation for tension shall material strength. The mean ultimate (maximum) torsion
include yielding on the gross area and fracture at any resistance and standard deviation shall be determined from
couplings. At couplings, there shall be consideration of the test population. Based on test results, maximum
fracture on the net area of the main member,fracture on the installation torque shall be reported as two standard
net area of the sleeve, bearing of fasteners such as pins or deviations below the mean ultimate(maximum)torque from
bolts on the net areas of fastener holes, shearing of the the sample population or any lower value chosen by the
fasteners, block shearing of the main member and sleeve, manufacturer.Torsional strength need not be evaluated for
and the attachment of the sleeve to the main member. corrosion losses.
3.11.2 Compression: Shaft evaluation for 3.11.3.2 Torsion Test on Combined Shaft (with
compression shall include buckling resistance, yielding on Coupling) and Helix Plate: In addition to specimens
the gross area, and yielding at any couplings.At couplings, prescribed in Section 3.11.3.1, a minimum of three
there shall be consideration of bearing of the fasteners such specimens for each helix configuration (variation in
as pins or bolts on the net area of the fastener holes, diameter,thickness,steel grade, pitch,and edge geometry)
shearing of the fasteners,and the attachment of the sleeve shall be tested.
to the main member.A bending moment shall be applied to
Page 7 of 24
•
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358)
3.11.4 Lateral Resistance: Lateral resistance of the 3.12.4 Torsional Test Requirements: A minimum of
shaft is necessarily coupled with soil capacity and shall be three specimens for each helix configuration (variation in
determined in accordance with Section 3.13 (3.13.3 and diameter,thickness,steel grade,pitch,and edge geometry)
3.13.4). Shaft area, moment of inertia, and elasticity shall shall be tested. Helix torsion resistance shall be tested in
be used as inputs in the analysis. Maximum bending accordance with Section 4.2.2.The failure of helix shall not
moment and shear stress determined from the analysis be the governing limit state out of the applicable limit states
shall be limited by the allowable bending and shear prescribed in Sections 4.2.2.1.3 and 4.2.2.2.3. The
resistance of the shaft or the shaft couplings,whichever is maximum installation torque capacity of the helix shall be
less. Deflection of shaft couplings shall be included in considered acceptable provided it exceeds the maximum
lateral resistance analysis. installation torque capacity of the shaft.
3.11.5 Elastic Shortening or Lengthening: Methods 3.13 P4 Soil Capacity: Soil capacity includes tension,
(equations) shall be provided for estimation of elastic compression, and for lateral resistance of a helical pile
shortening/lengthening of the shaft under the allowable embedded in ground, as applicable.
axial load plus any slip in the couplings. These methods 3.13.1 Torque Correlations: Evaluation reports shall
shall be based upon Conventional Design. include a correlation between final installation torque, T,
3.11.6 Combined Stresses: Shaft evaluation shall and predicted ultimate (maximum)axial capacity, Q, given
include combined stresses. Combinations of tension, by Eq-8:
compression, bending, and lateral loads shall be
considered as applicable. Q = KtT (Eq-8)
3.11.7 Test Requirements: Tests shall not be where Kr is the axial tensile or compressive load capacity to
required for evaluation of shaft tension, compression, and torque ratio for a given helical pile type. The predicted
bending moment provided all analysis is accomplished allowable capacity, Qa, shall be computed by Eq-9:
using Conventional Design in accordance with Section Qa = 0.5Q (Eq-9)
3.7.1. A minimum of three verification load tests shall be This torque correlation,including(Eq-8),(Eq-9)and the
conducted on separate specimens in each direction Kr values prescribed in Sections 3.13.1.1 and 3.13.1.2,
(compression, tension, bending) on any component of a applies only to shaft sizes described in Item 1 of Table 3.
shaft evaluated using Special Analysis. Tests are required For shaft sizes that are outside of this prescribed range,this
to determine torsion resistance of all shafts and coupling torque correlation is outside the scope of this criteria.
rigidity in accordance with Sections 3.11.3 and 3.11.2.3,
respectively. Tests for shaft capacity shall be conducted in The parameter Kr shall be verified by full-scale field
accordance with Section 4.2. installation and load tests. The number of tests required
3.12 Helix Capacity: Helix capacities shall be evaluated depends on whether the helical pile system is conforming
for torsional resistance, punching flexure,weld flexure,and or nonconforming. Separate torque correlations are
weld shear in tension and compression.Evaluation shall be required for shafts with differing geometry and outside
based solely on testing. The allowable helix capacity, P3, dimensions and for each helix plate style (pitch,thickness,
for helical pile systems and devices with multiple helices geometry). Field tests may be conducted at any site
shall be taken as the sum of the least design allowable provided a geotechnical engineering report is obtained for
capacity of each individual helix. the site in accordance with Section 3.13.3 and the soil
profile generally matches that shown in Tables 2A and 2B.
3.12.1 Lateral Capacity: The determination of the The final installation torque shall be based on the torque
lateral capacity of the helix is not permitted. The lateral resistance readings taken during the field load tests in a
capacity of a helical pile system is based on the resistance manner recommended by the helical pile manufacturer.The
of the shaft only and is not significantly affected by the testing laboratory shall describe the method used to
presence of helix bearing plates. determine the final installation torque.The evaluation report
3.12.2 Torsion: Torsion resistance of helix bearing shall include a description of the method used to determine
plates can be determined in conjunction with shaft torsion the final installation torque that corresponds to the field load
or independently. In the first case, testing shall be tests.
conducted in accordance with Section 4.2.2 using the 3.13.1.1 Conforming Systems: Systems shall be
number of samples and the same procedures described in considered conforming based on compliance with the
Section 3.11.3.2. In the second case, testing shall be criteria given in Table 3. The following capacity to torque
conducted in accordance with Section 4.2.2 using the ratios (Kr)obtained from full-scale axial load tests shall be
number of samples and the same procedures described in reported for the prescribed shaft sizes as follows:
Section 3.12.4.
1.5-inch-and 1.75-inch-square shafts Kr=10 ft-'
3.12.3 Axial Test Requirements: Each diameter,
thickness, steel grade, pitch, and edge geometry helix, for 2.875-inch outside diameter round shafts Kr=9 ft
which evaluation is being sought, shall be tested. The 3.0-inch outside diameter round shafts Kr=8 ft-'
allowable capacity for each size and type of helix shall be
reported as the average result of at least three test 3.5-inch outside diameter round shafts Kt=7 ft'
specimens. In order to allow the mean values, individual For any other shaft sizes,which do not have an assigned
results determined from testing shall be within 15 percent Kr value by Section 3.13.1.1, but are within the range noted
of the average of tests.Otherwise,the least test result shall in Item 1 of Table 3, the capacity to torque ratios (Kr)
apply. Helix punching, weld flexure, and weld shear tests obtained from full-scale axial load tests shall be limited by
shall be conducted in accordance with Section 4.3. the Kr values predicted by the(Eq-10)below:
Page 8 of 24
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358)
K` =
22.285(deff) 0.9195
( q- )E 10 include any testing completed under Section 3.13.1.1 and
Table 2A.The established Kt values reported from the full-
where: scale axial load tests, for the prescribed shaft sizes noted
Kt = Load capacity to torque ratio, which shall be below, shall be limited as follows:
rounded down to nearest 0.5,ft-1 1.5-inch-and 1.75-inch-square shafts Kt<_10 ft-1
defy = Effective shaft diameter; for round shafts, den. is 2.875-inch outside diameter round shafts Kt<9 ft-1
the same as the shaft outside diameter;for square 3.0-inch outside diameter round shafts Kt<8 ft-1
shafts, deft is the diameter of a circle
circumscribing around the shaft or the diagonal 3.5-inch outside diameter round shafts Kt<_7 ft-1
distance between opposite corners of the square For any other shaft sizes,which do not have an assigned
shaft; in. Kr value by Sections 3.13.1.1 and 3.13.1.2, but are within
The number of tests required to verify capacity to the range noted in Item 1 of Table 3,the capacity to torque
torque ratios for conforming products shall be as shown in ratios (Kt)obtained from full-scale axial load tests shall be
Table 2A. The correlation between torque and capacity limited by the Kr values predicted by(Eq-10).
shall be deemed verified if all of the ultimate(maximum)soil The subsurface profile at each test site shall be
capacities, Qr, determined from load tests conducted in determined in accordance with Section 3.13.4.
accordance with Section 3.13.1 exceed the predicted Test sample population shall be plotted versus the
allowable capacity, Qa, determined using the forgoing Kr ratio Qr/Qa. An iterative approach shall be used to
values and provided the average ratio of ultimate determine the value of Kt such that the mean value of Qr/Qa
(maximum) soil capacity, Qr, determined in field tests to is equal to 2.0. The Kt value shall be considered valid if
predicted allowable capacity, Qa, determined using Kt is every test has a QdQa ratio greater than or equal to 1.0.
equal to or greater than two (2.0). If verification is not Otherwise, a correlation between capacity and torque is
obtained, these helical pile systems and devices shall be invalid for that product and cannot be reported.
deemed as non-conforming and shall be subject to the
additional testing as set forth in Section 3.13.1.2, unless a For evaluation of piles with a single helix, the torque
lower Kt value is sought by the manufacturer. correlation tests must comply with Section 3.13.1.2,except
To determine a lower Kt value, the test sample that the test specimens must meet the following
population shall be plotted versus the ratio of Qt/Qa. An requirements:
iterative approach shall be used to determine the Kt value, a. For each individual helix pile diameter, there
such that the mean value of Qr/Qa is equal to 2.0. The Kt must be at least two replicate compression tests in each of
value shall be considered valid if every test has a QIQa ratio two different soil conditions,chosen from the three possible
greater than or equal to 1.0. Otherwise, a correlation soil conditions of sand,clay and hard bedrock.At least two
between capacity and torque is invalid for that product and replicate tests must be conducted in hard bedrock for the
cannot be reported without additional testing as required for smallest and largest diameter helix piles, respectively.
nonconforming systems in Section 3.13.1.2. The Kt value b. For each individual helix pile diameter, there
shall be rounded down to the nearest 0.5. must be at least two replicate tension tests in each of two
For evaluation of piles with a single helix, the torque different soil conditions,chosen from the three possible soil
correlation tests must comply with Section 3.13.1.1, except conditions of sand, clay and hard bedrock.
that the test specimens must meet the following c. The total number of compression tests for all
requirements: single helix piles must be at least 16.
a. For each individual helix pile diameter, there d. The total number of tension tests for all single
must be at least one compression test in each of two helix piles must be at least 12.
different soil conditions,chosen from the three possible soil
conditions of sand,clay and hard bedrock.At least one test 3.13.2 Lateral Resistance: Allowable soil capacity in
must be conducted in hard bedrock for the smallest and the lateral direction shall be determined through load tests
largest diameter helix piles, respectively. on specimens installed in different soil conditions. The
allowable soil capacity shall be determined based on
b. For each individual helix pile diameter, there
deflection criteria set forth in Section 4.4.2. In order to be
must be at least one tension test in each of two different soil
conditions,chosen from the three possible soil conditions of valid, allowable capacities determined for each type of
sand, clay and hard bedrock. specimen in each soil type shall be within 15 percent of the
average allowable capacity for those tests.
c. The total number of compression tests for all A minimum of four specimens of each type of helical
single helix piles must be at least eight. pile shaft shall be tested in each soil type for which
d. The total number of tension tests for all single evaluation is being sought. Variations in shaft size, shaft
helix piles must be at least six. geometry, and material strength shall constitute a different
3.13.1.2 Nonconforming Systems: Systems that type of specimen. Variations in helix size, geometry, pitch,
do not comply with the criteria in Table 3 or that fail material strength, thickness, and number do not require
verification tests given in Section 3.13.1.1 shall be deemed separate tests. Four separate specimens shall be tested in
nonconforming. In order to establish Kt values for these each transverse direction for which evaluation is being
systems,field tests shall be conducted in compression and sought if the shaft is not axially symmetric.Test specimens
tension such that the total number of tests is as shown in shall consist of a shaft, at least one shaft coupling located
Table 2B. Testing in conformance with Table 2B may within the manufacturer's smallest extension length from
Page 9 of 24
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358)
the ground surface, and one or more helix bearing plates. 3.14.2 Requirements for Top Bracket Connections:
The test may include a bracket. The strength of top bracket connections to the shaft and to
At a minimum,evaluation shall include tests in firm clay the foundation of the structure shall comply with 2024,
soils. Additional tests may be conducted in different soil 2021,2018,2015,2012 and 2009 IBC Section 1810.3.11.2
conditions from other sites.Additional information on testing (applicable sections of 2006 IBC Section 1808.2.23), as
is provided in Section 3.13.3. Allowable soil capacity for applicable. At a minimum, design of the connection to the
different specimens in different soil categories shall be foundation shall be based on normal-weight concrete with
tabulated in the evaluation report. The evaluation report a specified compressive strength of 3,000 psi (20.68 MPa).
shall contain a statement that soil capacity for lateral 3.14.3 Requirements for Pile Shafts: The shaft
resistance in soils conditions that substantially differ from (excluding couplers) shall have a uniform cross section
actual test sites included in the evaluation shall be along the entire shaft seismic flexural length.The shaft and
determined by a registered design professional on a case- couplers shall comply with the limiting width-to-thickness
by-case basis. ratios for compression elements for moderately ductile
members prescribed in Table D1.1 b of AISC 341-22(Table
3.13.3 Test Requirements: For each test site, D1.1 of AISC 341-16, including footnote c; and Table D1.1
geotechnical investigations shall be conducted in of AISC 341-10, including footnote e) for round hollow
accordance with 2024, 2021, 2018, 2015, 2012 and 2009 structural sections(HSSs).
IBC Section 1803.2 and reported in accordance with 2021,
2018,2015,2012 and 2009 IBC Section 1803.6. 4.0 TEST METHODS
3.13.3.1 Torque Correlation: Axial compressive 4.1 P1 Bracket Capacity: Where specified herein,
and tensile torque-correlated soil capacity shall be each size and configuration of the bracket shall be tested.
determined through field load tests as provided in Section The configuration of the bracket and direction of applied
3.13.1. Axial compressive and tension load tests to loads in the test apparatus shall be as close to actual field
establish the torque correlation factor shall be conducted for conditions as practical. Pertinent data such as maximum
each shaft size for which evaluation is sought. At a load applied,failure mode, etc. shall be reported.
minimum, two of the load tests required for each 4.1.1 Type A Side Load:
compression and tension shall be conducted by installing
the helical piles at the maximum installation torque 4.1.1.1 Setup: Compression and tension tests can
determined in accordance with Section 3.11.3 or as be conducted in a horizontal configuration, as illustrated in
recommended by the manufacturer,whichever is lower.For Figure 6. The bracket shall be mounted to a block of plain
tests where installation is to the maximum installation concrete of known strength that is fixed with respect to
torque (axial verification testing), the maximum load translation and rotation. The connection of the bracket to
capacity shall be when either plunging of the helix plate the concrete shall be in accordance with manufacturer's
occurs or when the helical pile can no longer sustain the installation instructions.Load shall be applied to the bracket
load, whichever occurs first. In each of these tests, the using a 60 inch (1524 mm)long section of helical pile shaft
maximum load capacity obtained shall be at least twice the secured to the bracket in a manner that duplicates actual
predicted allowable capacity obtained from Equation 9 of field conditions. The shaft shall have a standard
this criteria;otherwise the allowable soil capacity, P4, shall manufactured coupling(s).The loaded end of the shaft shall
be limited based on the lowest maximum load capacity be rotationally fixed. Axial load shall be applied in the
determined through testing with installation at the maximum direction of the longitudinal axis of the helical pile shaft.Any
installation torque. eccentricity inherent in the bracket configuration and
manufacturer-recommended angle of the shaft to bracket
For soil capacity torque correlation, the tests for axial shall be accounted for and shall be modeled to match the
compression and tension soil capacity (including the test anticipated design purpose.
piles installed to a maximum torque) shall be conducted in
accordance with Section 4.4.1,except with the modification 4.1.1.2 Procedure: Axial deflection shall be
described in this section (Section 3.13.3.1) for axial recorded as a function of applied load at regular intervals
verification testing.Tension and compression load tests are equal to or less than 20 percent of the anticipated allowable
required to be conducted at the facility or field station of a load. The rate of load application shall be sufficiently slow
testing laboratory complying with Section 2.2. to simulate static conditions. Each load increment shall be
held for a minimum of 1 minute. The allowable strength of
3.13.3.2 Lateral Capacity: Allowable lateral load the bracket shall be determined from ultimate (maximum)
capacity shall be determined through field load tests in strength using the equations provided in Section 3.7.3.
accordance with Section 3.13.2. Four load tests are Compressive strength tests shall be conducted within 24
required for each combination of shaft size, material hours of the bracket test on concrete cylinders cast at the
strength, shaft geometry, and soil type. The helical plates same time as the test specimen to establish concrete
for which evaluation is sought shall be included in the compressive strength. Cylinders shall be stored and cured
assembly.Tests for lateral resistance shall be conducted in according to Section 10.2.1 of ASTM C31 (field cure). A
accordance with Section 4.4.2. strength test is the average of the strengths of at least two
3.14 Special Seismic Requirements: 6-inch-by-12-inch(152 mm by 305 mm)cylinders or at least
3.14.1 General: For optional evaluation for use in three 4-inch-by-8-inch(102 mm by 204 mm)cylinders made
from same sample of concrete. The tested concrete
structures assigned to Seismic Design Categories (SDCs)
D through F, the helical pile systems and devices shall compressive strength shall be within 15 percent of the
specified compressive strength. Concrete cylinder
comply with the additional requirements prescribed in
compression tests shall be conducted in accordance with
Sections 3.14.2 and 3.14.3. ASTM C39.
Page 10 of 24
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358)
4.1.2 Type B: Direct Load: shear. The allowable strengths of the bracket shall be
4.1.2.1 Setup:The test bracket shall be mounted to determined from yield or ultimate (maximum) strength and
a fixture that is substantially similar to the structure for which the equations provided in Section 3.7.3,whichever formula
the bracket is intended to support.The fixture representing results in the lowest value.The compressive strength of the
the structure shall be translationally and rotationally fixed as concrete shall be verified in accordance with the
appropriate to simulate field conditions, as illustrated in procedures described in Section 4.1.1.2.
Figure 7. The connection of the bracket to the fixture shall 4.1.4 Type D:Tension Anchor:
be in accordance with manufacturer's installation 4.1.4.1 Setup: Load tests shall be conducted on
instructions. The load shall be applied to the bracket using
a 60-inch-long (1524 mm) section of helical pile shaft Type D anchor brackets by attaching the bracket to a short
secured to the bracket in a manner that duplicates actual section of helical pile shaft following the evaluation report
field conditions. The loaded end of the shaft shall be applicant's recommendations. The bracket shall be cast
rotationally fixed.Axial load shall be applied in the direction into a concrete test specimen or otherwise attached to a
of the longitudinal axis of the helical pile shaft. Any structure that substantially conforms to the manufacturer's
inclination of the shaft with respect to the structure shall be recommended connection details including minimum
modeled to match the anticipated design purpose. For tests washer plate size, concrete cover, and concrete
of the lateral capacity of a bracket and the connection of the reinforcement as applicable.The specimen shall be placed
bracket to a structure, the load test shall be set-up as in tension in a laboratory load frame,as illustrated in Figure
described herein, except that the load shall be applied 9. Deflection of the anchor bracket shall be measured with
normal to the shaft at a location as close to the base of the a dial gauge.The load shall be determined with a calibrated
cap as possible. In order to avoid application of flexure to load cell.The length of the shaft used in the test shall be at
the shaft during loading, a roller guide shall be used to least six times the shaft diameter.
facilitate load application as shown in Figure 7. 4.1.4.2 Procedure: The specimen shall be loaded
4.1.2.2 Procedure: Depending on the purpose of in increments not exceeding 20 percent of the calculated
the test, axial or lateral deflection shall be recorded as a allowable capacity. The rate of load application shall be
function of applied load at regular intervals equal to or less sufficiently slow to simulate static conditions. Each load
than 20 percent of the anticipated allowable load. The rate increment shall be held for a minimum of 1 minute.
of load application shall be sufficiently slow to simulate Deflections and loads at the completion of the hold period
static conditions. Each load increment shall be held for a for each increment shall be measured.The specimens shall
minimum of 1 minute. Yield strength and ultimate be loaded until plastic yielding or brittle fracture occurs.The
(maximum) strengths of the bracket shall be determined failure mode shall be reported. A plot of deflection versus
using conventional analysis of a plot of load versus load shall be reported.The allowable strength of the bracket
deflection. The allowable strength of the bracket shall be shall be determined from yield or ultimate (maximum)
determined from yield or ultimate (maximum) strength and strength and the equations provided in Section 3.7.3,
the equations provided in Section 3.7.3,whichever formula whichever equation results in a lower value, along with the
results in a lower value. If a concrete structure is used in the corresponding deflection as determined from the load-
load test, the strength of the concrete shall be tested in deflection plot. If applicable, the strength of the concrete
accordance with the procedures in Section 4.1.1.2. shall be verified in accordance with the procedures
described in Section 4.1.1.2.
4.1.3 Type C: Slab Support:
4.2 P2 Shaft Capacity:
4.1.3.1 Setup: Compression tests shall be
conducted by casting a concrete slab with specified 4.2.1 Axial Tension and Compression:
thickness and dimensions equal to the manufacturer's 4.2.1.1 Setup: Tension and compression tests
recommended helical pile shaft spacing for that thickness shall be conducted on a section of shaft with a standard
slab and anticipated loading.The slab support bracket and manufactured coupling located approximately at the
a section of helical pile shaft shall be mounted in an inverted midpoint of the shaft specimen.The test specimen shall be
fashion over the slab, as illustrated in Figure 8. A hole mounted to a vertical or horizontal load frame with one end
consistent with manufacturer's recommendations shall be attached to a fixed platform and the other end attached to a
cored through the slab in the bracket location and mobile platform with the capability to apply the load to the
subsequently filled with cementitious grout. The slab shall specimen in the axial direction. The coupling connection
be supported on a flexible air diaphragm sufficient to shall be done in accordance with manufacturer's specific
withstand the imposed loads.The length of the helical shaft published recommendations. Direction of loading shall be
used in the test shall be at least six times the diameter of coaxial with the longitudinal axis of the shaft. The testing
the shaft.As an alternative,the slab, bracket,shaft, and air apparatus shall provide sufficient rigidity as to minimize any
diaphragm may be mounted in a horizontal load frame. slip or deformation not associated with the test specimen.
4.1.3.2 Procedure: Downward compression loads The shaft shall have sufficient length(each side of coupling)
shall be applied axially to the end of the shaft. Axial to allow a uniform tensile or compressive force to develop
deflections shall be recorded as a function of applied load in the shaft prior to reaching the connection. To evaluate
at regular intervals not exceeding 20 percent of the buckling resistance, compression specimens shall have a
anticipated allowable load.The rate of load application shall minimum length equal to or greater than the effective length
be sufficiently slow to simulate static conditions. Each load as specified in Section 3.11.2.2.
increment shall be held for a minimum of 1 minute. Yield 4.2.1.2 Procedure: Loads shall be applied to the
strength and ultimate (maximum) strengths of the bracket specimen in increments not exceeding 20 percent of the
shall be determined using conventional analysis of a plot of design allowable load of the specimen. Each load
load versus deflection and may depend heavily on slab increment shall be held for a minimum of one minute. The
Page 11 of 24
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358)
specimen shall be loaded to failure.Application of the load compression load frame, as illustrated in Figure 11. For
shall be performed at a slow rate to simulate a statically shafts with a non-circular cross section, as a minimum,the
applied load.Pertinent data such as maximum load applied, tests shall be conducted with the least resistant orientation.
maximum shaft or connection deformation, failure mode, The distance between shaft supports shall be at least 36
etc. shall be reported. Yield strength and ultimate inches (914 mm) or 12 times the maximum outside cross-
(maximum) strength of the shaft and coupling shall be sectional dimension of the shaft, whichever is greater. A
determined using conventional analysis of a plot of load standard manufacturer coupling shall be located
versus deflection. The allowable strength of the shaft and approximately in the center of the specimen.Loads shall be
coupling shall be determined from yield or ultimate applied using a two point test where the load points straddle
(maximum)strength and the equations provided in Section the coupling so that a uniform bending moment is produced
3.7.3,whichever equation results in a lower value. in the coupling.
4.2.2 Torsion: 4.2.3.2 Procedures: Load shall be applied and
4.2.2.1 Setup and Procedure: deflections measured at intervals of less than or equal to 20
percent of the load corresponding to the theoretical
4.2.2.1.1 For Combined Shaft (with Coupling) allowable bending moment. Application of load shall be
and Helix: Torsion testing shall be performed on a section performed at a slow rate to simulate a statically applied
of shaft with a minimum length of 36 inches(914 mm)or 12 load. Pertinent data such as maximum load applied,
times the maximum outside cross sectional dimension of maximum shaft or coupling deformation, failure mode, etc.
the shaft; whichever is greater. The shaft shall have a shall be reported. Yield strength and ultimate (maximum)
standard manufactured coupling located approximately strength of the shaft and coupling shall be determined using
midway between the ends of the shaft specimen and a helix conventional analysis of a plot of load versus deflection.
affixed to the end of the shaft.The specimen shall be fixed The allowable bending strength of the shaft and coupling
at the helix end and attached to a torque motor on the other shall be determined from yield or(maximum)strength and
end. The helix shall be fixed about the outside edge using the equations provided in Section 3.7.3,whichever equation
six bolt clamps.The tests shall be conducted in a load frame results in a lower value.
that allows for measurement of the angle of twist, as 4.2.4 Coupling Rigidity:
illustrated in Figure 10. Torque shall be applied to a short
section of shaft attached to the helix. The test setup shall 4.2.4.1 Setup: The maximum lateral deflection of
include a means of measuring shaft coupling bolt hole shafts due to coupling flexure shall be determined using a
elongation during the test. The rotation rate shall not section of shaft with length equal to the Unsupported
exceed 20 rpm. Length [60 or 120 inches (1524 or 3048 mm)as specified
4.2.2.1.2 For Shaft (Without Helix and with by 2024, 2021, 2018, 2015, 2012 and 2009 IBC Section
1810.2.1 [2006 IBC Section 1808.2.9.2]. The shaft shall
Coupling): Same as Section 4.2.2.1.1,except that the test have the maximum number of couplings possible over its
specimen shall not include a helix and the specimen shall length based on the available shaft sections.The shaft shall
be fixed at one end of the shaft and attached to the torque be horizontally or vertically arranged in a load frame at the
motor on the other end. evaluation report applicant's option with one end fixed and
4.2.2.1.3 For Helix (Without Coupling): Same the other end unsupported, as illustrated in Figure 12. A
as Section 4.2.2.1.1,except that the test specimen shall not load shall be applied perpendicularly to the unsupported
include a coupling and the specimen shall consist of a short end of the shaft.
section of shaft attached to a helix plate.The helix shall be 4.2.4.2 Procedures: A load perpendicular to the
fixed about the outside edge as described in Section longitudinal axis of the shaft specimen shall be equal to 0.4
4.2.2.1.1 and torsion shall be applied to the end of the shaft. percent of the allowable compression load on the helical
4.2.2.2 Conditions of Acceptance: Depending on pile shaft system shall be applied.The total deflection of the
the torsion test specimen configuration, the ultimate loaded end of the shaft with and without coupler(s),
(maximum) torsion resistance shall be defined as that including any free deflection, shall be measured relative to
required to achieve 0.5 shaft revolution per foot (1.6 a plane perpendicular to the applied load direction and
revolutions per meter) of shaft length, that which causes extending from the fixed end of the fixture. The coupler
failure of the helix, coupling, or shaft, that which damages deflection shall be determined by subtracting the total
the coupling to an extent that it cannot be decoupled deflection of the shaft specimen without the coupler(s)from
effectively, or that which elongates the coupling bolt hole the total deflection of the shaft specimen with the
0.25 inch(6.4 mm),whichever occurs first,as applicable. coupler(s). The coupler deflection shall be reported and
4.2.2.2.1 For Combined Shaft (with Coupling) used in shaft eccentricity computations.
with Helix: Same as Section 4.2.2.2,except weld failure of 4.2.5 Shear Strength:
the helix is not acceptable 4.2.5.1 Setup: The maximum shear strength of
4.2.2.2.2 For Shaft(With Coupling and without shafts and couplings shall be determined using specimens
Helix): Same as Section 4.2.2.2 with lengths as appropriate for the test apparatus. The
4.2.2.2.3 (Without Same specimen shall be horizontally or vertically arranged in a
as Section .4.2.2.2,Forex Helixt weld(Witfailuhout
e Coupling):of the helix is not load frame with one end fixed and the other end free.A load
acceptable. shall be applied normal to the shaft or coupling using a roller
or slide to avoid inducing flexure into the system.
4.2.3 Bending: 4.2.5.2 Procedure: The loads shall be applied in
4.2.3.1 Setup:Bending tests shall be conducted on increments not exceeding 20 percent of the allowable shear
a section of shaft that is horizontally arranged in a load on the shaft or coupling. The total deflection of the
Page 12 of 24
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358)
shaft or coupling at the point of load application shall be net deflection exceeds 10 percent of the helix plate
measured at each increment. Load shall be applied at a diameter, whichever occurs first. Net deflection shall be
slow rate to simulate statically applied load. Each load total deflection minus shaft elastic shortening or
increment shall be held for a minimum of one minute. The lengthening. For multiple helix configurations, the average
allowable strength shall be determined from the yield and helix diameter shall be used in this criterion.
ultimate (maximum)strength of the shaft or coupling using
a conventional analysis of a plot of load versus deflection
and the equations provided in Section 3.7.3, whichever 4.4.2 Lateral Load Tests:
equation results in a lower value. 4.4.2.1 Setup: Lateral load tests shall be
4.3 P3 Helix Capacity: conducted in accordance with the standard loading
4.3.1 Setup: Helix capacity tests shall be performed procedure in Section 10.1.2 of ASTM D3966. These tests
by placing a short section of shaft with a helix in a laboratory can be performed in two ways. If verification of lateral
load frame, as illustrated in Figure 13.The helix plate shall resistance of brackets is required, the test setup shall
bear on an adjustable mandrel with five or more pins or a consist of a helical pile representative of a standard
helix-shaped fixture. The line of bearing, Rib, shall be installation with a bracket above the ground surface. The
located at a distance from the central axis of the shaft equal bracket shall be connected to a structure constructed from
to one-half the sum of the outer radius of the helix, Rb, and wood, steel, or concrete depending on the particular detail
the radius of the shaft, R . For non-circular shafts, Rs shall for which evaluation is being sought.The test setup shall be
be the radius of a circle circumscribed about the outer such that lateral load is applied to the structure being
extent of the shaft's cross-section. Direction of loading shall supported immediately above the bracket elevation. The
be coaxial with the longitudinal axis of the shaft and normal tests shall be conducted with a free head arrangement in
to the bearing plane of the helix. accordance with ASTM D3966. Where the bracket is
intended to support a structure that is rotationally
4.3.2 Procedures: Load shall be applied, and restrained, the test may be conducted using fixed head or
deflection recorded at intervals equal to 20 percent of the free head arrangements in accordance with ASTM D3966.
theoretical punching strength of the helix. Application of If verification of bracket capacity is not required, as in
load shall be done at a slow enough rate as to simulate a the case of Conventional Design, then the tests shall be
statically applied load. Pertinent data such as maximum conducted with the helical pile shaft extending a minimum
load applied, maximum helix deformation, failure mode, of 12 inches (304.8 mm) from the ground surface. The
etc., shall be reported. Load shall be plotted as a function lateral load shall be applied to the helical pile shaft
of deflection. Maximum strength of the helix shall be the immediately above the ground surface. Depending on
peak load sustained by the helix. The allowable strength of whether the helical pile shaft is intended to support a
the helix shall be determined from the maximum strength in structure that is rotationally restrained, the test may be
accordance with Section 3.7.3. conducted using fixed head or free head arrangements in
4.4 P4 Soil Capacity: accordance with ASTM D3966.
4.4.1 Axial Load Tests: Bracket and helical pile installation shall be done in
4.4.1.1 Setup: Full-scale load tests shall be accordance with the standards set forth in manufacturer's
conducted in accordance with ASTM D1143 for axial specific published recommendations.All test piers shall be
installed within the manufacturer's specified tolerances for
compression and ASTM D3689 for axial tension.The quick
load test procedure set forth in Section 10.1.2 of ASTM angle of installation for the bracket type. Where brackets
D1143 and ASTM D3689 shall be used in compression and are not used, the shaft shall be installed within the
tension tests, respectively. Installation of the helical piers manufacturer's specified tolerances for plumbness. The
shall be done in accordance with the installation minimum depth of the uppermost helix shall be 180 inches
instructions. The brand, model number, and maximum (4572 mm) unless the helical pile system is only available
torque capacity of the installation torque indicator shall be in a shorter length.
reported.All test piers shall be installed as close to vertical 4.4.2.2 Procedures: For tests including brackets or
as possible. Pertinent data such as helical pile shaft depth shafts (with coupling) that are not symmetrical, separate
and final installation torque achieved shall be reported. specimens shall be loaded in all lateral directions for which
Torque should be measured with a calibrated in-line evaluation is being sought.Application of load shall be done
indicator, or calibrated hydraulic torque motor via at a slow rate to simulate a statically applied load. The
differential pressure. Calibration of torque motors and/or allowable load capacity reported shall be equal to half the
torque indicators shall be performed on equipment whose load required to cause 1 inch (25 mm)of lateral deflection
calibration is traceable back to NIST (National Institute of at the ground surface.
Standards and Technology). For tension tests, the helical 4.5 General Testing Requirements: Test equipment
pile shaft shall be installed such that the minimum depth shall be adequate to impose anticipated maximum loads. If
from the ground surface to the uppermost helix is 12D, loading is not carried to failure, the highest value achieved
where D is the diameter of the largest helix.
will be considered the maximum load.
4.4.1.2 Procedures: Direction of loading shall be 5.0 QUALITY CONTROL
coaxial with the longitudinal axis of the pier. Application of
load shall be done at a slow rate to simulate a statically 5.1 Manufacturing:All products shall be manufactured
applied load. Piers shall be installed to the depth interval under an approved quality control program with inspections
recommended for the designated helical pile shaft test by ICC-ES or by a properly accredited inspection agency
sites. Maximum load capacity shall be that which is that has a contractual relationship with ICC-ES.
achieved when plunging of the helix plate occurs or when
Page 13 of 24
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358)
5.2 Quality Control Documentation: Quality types described in the evaluation report.For any helical pile
documentation complying with the ICC-ES Acceptance device subject to combined lateral and axial compression
Criteria for Quality Documentation (AC10) shall be or axial tension, the evaluation report shall contain the
submitted. maximum allowable lateral strength and the maximum
5.3 A qualifying inspection shall be conducted at each allowable axial strength and shall state that the strength of
manufacturing facility when required by the ICC-ES the device (P2) is governed by the interaction equation
Acceptance Criteria for Inspection Agencies(AC304). given in the AISC reference standard and the combined
lateral and axial capacity for soil (P4) is outside the scope
6.0 EVALUATION REPORT REQUIREMENTS of the evaluation report.
6.1 General: The evaluation report shall include a The evaluation report shall provide a discussion of
description of the helical pile device or system, typical elastic shortening/lengthening,anticipated settlements,and
applications, and limitations. The evaluation report shall typical elastic deflections, as applicable, depending on the
address the following: end use. The discussion shall contain design values from
(1)The device or system having been evaluated for use analysis or load tests. A statement shall be included to
to support structures in Seismic Design Categories A, B, indicate that settlement of the helical pile shall be
and C determined in accordance with the IBC.If compliance determined by a registered design professional as required
with the additional requirements of Section 3.14 is in 2024, 2021, 2018, 2015, 2012 and 2009 IBC Section
established,then the evaluation report is to indicate that the 1810.2.3.
helical pile systems and helical pile devices have been 6.2 Brackets: Bracket capacities, P1, shall include
evaluated for supporting structures in Seismic Design reference to the type of shaft and shall include provisions
Categories A through F determined in accordance with IBC. for, P2, shaft capacity. The table of side load bracket
Otherwise, an additional statement indicating that the use capacities also shall include a list of values or an equation
of the device or system to support structures located in for determining the maximum overturning moment specific
Seismic Design Category D, E, or F, determined in to that type of bracket as a function of axial load supported.
accordance with the IBC is outside the scope of this report. The allowable capacities of brackets connected to or
(2)Use of the device or system in exposure conditions to embedded in concrete shall provide values for systems
soil that are indicative of a potential pile corrosion situation installed in the different concrete strengths that were
as defined by the following: (1) soil resistivity less than evaluated. Installation shall be limited to uncracked
1,000 ohm-cm; (2)soil pH less than 5.5: (3)soils with high concrete as defined in the applicable code. Allowable
organic content: (4)soil sulfate concentrations greater than capacities for direct load brackets shall clearly identify the
1,000 ppm: (5) soils located in landfills: or (6) soils construction details for which those capacities are
containing mine waste; is beyond the scope of the applicable. For slab support brackets, a table shall be
evaluation report. provided showing recommended bracket spacing for
System and device descriptions shall include the support of different slabs under different loading conditions
as described in Section 3.10.3. The table of capacities for
dimensions of primary components as well as engineering brackets and shafts shall indicate whether the structure to
drawings of the product. Any bracket connections to be supported has to be sideways braced or rotationally
structures shall be prescriptively specified in construction fixed based on assumptions used in the design and testing
details, including type and condition of structure to be of the product.Use of Type A brackets for supporting lateral
supported, drill holes, bolts, washer plates, field welds, loads is permitted, provided that the lateral load capacities
minimum concrete cover, concrete reinforcement, and of the brackets are designed by a registered design
leveling grout, as applicable. The recommended angle of professional in accordance with IBC Chapter 18.
shaft installation and maximum permissible departure from
that angle shall be specified for each bracket. Construction 6.3 Shafts:Shaft capacities shall be tabulated for each
details for bracket connections shall indicate that materials size of shaft for the conditions of being braced or unbraced
with different corrosion protection coatings shall not be in soft and firm soils as applicable. The evaluation report
combined in the same system, unless permitted by Section shall define these conditions by reference to Chapter 18 of
3.9, and that helical pile devices and systems shall not be the IBC.Standard penetration resistance blow count ranges
placed in electrical contact (galvanically isolated) with for firm and soft soils described in Section 3.11.2.1 of this
structural steel,reinforcing steel,or any other metal building criteria shall be repeated in evaluation reports. The
components. evaluation report shall state that the shaft capacity of helical
A table of allowable capacities (tension, compression, piles in air, water or fluid soils shall be determined by a
registered design professional. For evaluation reports
and/or lateral) for all elements (P1, P2, P3, and P4, as
applicable) shall be provided with listings for each system including provisions for lateral resistance, the structural
properties of the shaft shall be provided including gross
or device and all possible combinations and configurations. area, section modulus, modulus of elasticity, maximum
The evaluation report shall state that the allowable capacity allowable bending moment,and maximum allowable shear.
of a helical pile device or system shall be governed by the
least allowable capacity, P1 through P4, as applicable. 6.4 Helices: Helix compression and tension capacities
If lateral resistance is included in the evaluation report, shall be tabulated for each diameter, thickness, edge
a table of soil capacity in the lateral direction based on load geometry, pitch, and material strength available. The
tests shall be provided for each type of shaft in each test evaluation report shall indicate that the allowable helix
soil condition. The evaluation report shall indicate that soil capacity, P3, for helical pile with multiple helices shall be
capacity in the lateral direction needs to be determined by taken as the sum of the least design allowable capacity of
a registered design professional unless the soil conditions each individual helix.
for the site in question are generally consistent with soil
Page 14 of 24
•
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358)
6.5 Soil Capacity:A soils capacity-to-torque ratio shall of the side load bracket to the foundation as it relates to
be listed in the evaluation report along with the equations seismic forces and the provisions found in the 2024, 2021,
set forth in this acceptance criteria. The evaluation report 2018, 2015, 2012 and 2009 IBC Section 1810.3.11, shall
shall indicate that the soil capacity for site-specific be designed by a registered design professional. The
conditions shall be determined by a registered design evaluation report shall state that compliance with the 2024,
professional in accordance with Items 1 and 3 of 2024, 2021, 2018, 2015, 2012 and 2009 IBC Section 1810.3.6,
2021, 2018, 2015, 2012 and 2009 IBC Section second paragraph, and Section 1810.3.6.1 shall be
1810.3.3.1.9. For lateral soil resistance, the evaluation designed by a registered design professional. A statement
report shall contain a table of capacities for all soil types shall be included indicating that the settlement of a helical
including soil classifications based on geotechnical pile system is outside the scope of the evaluation report and
investigations conducted on the test site used in the lateral shall be determined by a registered design professional
load testing. The evaluation report shall state that lateral based upon shaft (including coupling) information
soil resistance shall be determined by a registered design prescribed in the evaluation report and in consultation with
professional for soil conditions that differ from those shown the pile manufacturer.
in the table. 6.8 Foundation and Soils Investigation Report: The
6.6 Materials: The evaluation report shall list the evaluation report shall indicate that a site-specific
material composition,including steel grades,of system and foundation and soils investigation report is required for
device components. Minimum material specifications for proper application of these products. The foundation and
structures to be supported on brackets included in the soils investigation report shall address corrosive properties
evaluation report shall be included, as applicable. of the soil to ensure that a potential pile corrosion situation
does not exist.The foundation and soils investigation report
6.7 Design: The evaluation report shall describe
shall address the support conditions for the shaft. The
general procedures for design and application of the helical
pile system or device and state whether bracket capacity is foundation and soils investigation report shall address the
axial compression, axial tension, and lateral load soil
based on a braced or unbraced helical system or device in capacities if values cannot be determined from the
accordance with 2024, 2021, 2018, 2015, 2012 and 2009 evaluation report. The foundation and soils investigation
IBC Section 1810. The design and detailing must comply report shall address effects of groundwater and other
with the applicable provisions found in the 2024, 2021, questionable characteristics.
2018, 2015, 2012 and 2009 IBC Section 1810.3. The
allowable axial design load of the helical pile shall be 6.9 Installation: The evaluation report shall note any
determined in accordance with 2024, 2021, 2018, 2015, special training or certification required for installation
2012 and 2009 IBC Section 1810.3.3.1.9. The individual professionals, equipment required for installation, and a
bearing method described in Item 1 of 2024, 2021, 2018, detailed description of proper installation techniques.
2015, 2012 and 2009 IBC Section 1810.3.3.1.9 must Requirements and procedures for quality assurance
consider the spacing of the helix plates in accordance with inspection of product installation shall be described,
the requirements shown in Table 3 of this criteria. An including procedures for field verification of ultimate
explanation of the structural analysis that shall be maximum soil capacity for tension and compression
performed by the design professional for proper application through correlations with final installation torque, as
of the system or device including consideration of the applicable.The evaluation report shall state that the helical
internal shears and moment due to structure eccentricity pile shall be installed in accordance with the 2024, 2021,
and maximum span between helical piles shall be provided. 2018, 2015, 2012 and 2009 IBC Section 1810.4.11. The
The magnitude of shear and moment forces exerted on the evaluation report shall state that the torque induced in the
structure due to the connection of the structure to the helical shaft shall not exceed the maximum installation torque.The
pile or device shall be provided.The results of this analysis evaluation report shall state that for tension applications,
and the structural capacities shall be used to select a helical the pier shall be installed such that the minimum depth from
pile system. The evaluation report shall state that to avoid the ground surface to the uppermost helix is 12D,where D
group efficiency effects an analysis prepared by a is the diameter of the largest helix. In cases where the
registered design professional shall be submitted where the installation depth is less than 12D, the minimum
center-to-center spacing of axially loaded helical piles is embedment depth shall be determined by a registered
less than three times the diameter of the largest helix plate design professional based on site-specific soil conditions
at the depth of bearing. An analysis prepared by a which must be subject to the approval of the code official.
registered design professional shall also be submitted For tension applications where the helical pile is installed at
where the center-to-center spacing of laterally loaded an embedment depth less than 12D,the torque-correlation
helical piles is less than eight times the least lateral soil capacity, P4, is outside the scope of this report.
dimension of the pile shaft at the ground surface, and the 6.10 Special Inspection: For installation,the evaluation
spacing between helical plates shall not be less than 3D, report shall state that special inspection in accordance with
where D is the diameter of the largest helical plate the 2024, 2021, 2018, 2015 and 2012 IBC Section 1705.9,
measured from the edge of the helical plate to the edge of 2009 IBC Section 1704. 10 or 2006 IBC Section 1704.9 is
the adjacent helical pile plate, or 4D, where the spacing is required, as applicable. Where on-site welding is required,
measured from the center to the center of the adjacent the evaluation report shall state that special inspection in
helical pile plates. The minimum embedment depth for accordance with 2024, 2021, 2018, 2015 and 2012 IBC
various loading conditions shall be included based on Section 1705.2, 2009 and 2006 IBC Section 1704.3 is
analysis and tested conditions. The evaluation report shall required,as applicable.The evaluation report shall state the
indicate that Section 1810 of the 2024, 2021, 2018, 2015, items to be observed by the special inspector. At a
2012 and 2009 IBC shall apply to these products. A minimum, these items shall include verification of
statement shall be included indicating that the connection manufacturer, equipment used, helical pier and bracket
Page 15 of 24
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358)
configuration and dimensions, tip elevations, the final
installation torque and final depth of the pile,other pertinent 7.0 ENVIRONMENTAL PRODUCT DECLARATION
installation data as required by the registered design (Optional):
professional in responsible charge and compliance of the
installation of helical pile system with the approved Environmental impacts shall be assessed via an
construction documents and this evaluation report. Environmental Product Declaration (EPD) based on a Life
6.11 Identification:The evaluation report shall describe Cycle Assessment (LCA). The LCA and EPD shall be
the identification method used by the manufacturer as set conducted in accordance with ISO 21930 and the
appropriate Product Category Rule(s)for the product type.
forth in Section 2.1.4.
■
6.12 Findings: The evaluation report shall list approved
manufacturing facilities and their inspection agencies.
Page 16 of 24
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358)
TABLE 1—REFERENCE STANDARD EDITIONS
2024 IBC 2021 IBC 2018 IBC 2015 IBC 2012 IBC 2009 IBC 2006 IBC
ANSI/AWC NDS ANSI/AWC NDS ANSI/AWC NDS ANSI/AWC NDS AF&PA NDS-2012 AF&PA NDS-2005 AF&PA NDS-
2024 2018 2018 2015 2005
AISC 360-22 AISC 360-16 AISC 360-16 AISC 360-10 AISC 360-10 AISC 360-05 AISC 360-05
AISC 341-22 AISC 341-16 AISC 341-16 AISC 341-10 AISC 341-10 AISC 341-05 AISC 341-05
ACI 318-2019 ACI 318-2019 ACI 318-2014 ACI 318-2014 ACI 318-2011 ACI 318-2008 ACI 318-2005
AWS D1.1-2020 AWS D1.1-2015 AWS D1.1-2015 AWS D1.1-2010 AWS D1.1-2010 AWS D1.1-2004 AWS D1.1-2004
TABLE 2A—SOIL CAPACITY ANALYSIS/TEST REQUIREMENTS OF CONFORMING SYSTEMS'
HELIX NUMBER OF HARD NUMBER OF NUMBER OF
COMBINATION HELICES SAND CLAY BEDROCK COMPRESSION TENSION
TESTS TESTS
Smallest diameter 1 C/T C 2 1
Largest Diameter 1 C/T C 2 1
Any two diameters 2 C/T C/T 2 2
Any three diameters 3 C/T C/T 2 2
Minimum Number of Tests Required 8 6
'C=Compression;T=Tension.
TABLE 2B—SOIL CAPACITY ANALYSIS/TEST REQUIREMENTS OF NONCONFORMING SYSTEMS'
HELIX NUMBER OF HARD NUMBER OF NUMBER OF
COMBINATION HELICES SAND CLAY BEDROCK COMPRESSION TENSION
TESTS TESTS
Smallest diameter 1 C/T C 4 2
Largest Diameter 1 C/T C 4 2
Any two diameters 2 C/T C/T 4 4
Any three diameters 3 C/T C/T 4 4
Minimum Number of Tests Required 16 12
'C=Compression;T=Tension.
TABLE 3—TORQUE CORRELATION CONFORMANCE CRITERIA
CRITERIA
1 Square shafts with dimensions between 1.5 inches by 1.5 inches and 3.0 inches by 3.0 inches,or round shafts with outside diameters
between 2.125 inches and 4.5 inches
2 True helix shaped plates that are normal with the shaft such that the leading and trailing edges that are within 1/4 inch of parallel.
3 Helix plate diameters between 8 inches and 14 inches with thickness between 3/6 inch and 1/2 inch.
4 Helix plates and shafts are smooth and absent of irregularities that extend more than 1/16 inch from the surface excluding connecting
hardware and fittings.
5 Helix spacing along the shaft shall be between 2.4 to 3.6 times helix diameter.
6 Helix pitch is 3 inches±1/4 inch.
7 All helix plates have the same pitch.
8 Helical plates are arranged such that they theoretically track the same path as the leading helix.
9 For shafts with multiple helices,the smallest diameter helix shall be mounted to the leading end of the shaft with progressively larger
diameter helices above.
10 Helical pile shaft advancement equals or exceeds 85%of helix pitch per revolution at time of final torque measurement.
11 Helix piers shall be installed at a rate less than 25 revolutions per minute.
12 Helix plates have generally circular edge geometry.
For SI: 1 inch=25.4 mm.
Page 17 of 24
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358) '
•
is
�I:If• 7n71
•
a
MN •m . m
BRACKET
ECCENTRICITY
MANUFACTURER
RECOMMENDEDMANUFACTURER
INSTALLATION RECOMMENDED
ANGLE±1' INSTALLATION
ANGLE t1'
10
IF-
.- i,
pp-
0 %7
•
FIGURE 1—TYPE A SIDE LOAD APPLICATION FIGURE 2—TYPE B DIRECT LOAD APPLICATION
CP
IIIIIIIIMP
1-
MANUFACTURER I,;
RECOMMENDED
0
I
ill
INSTALLATION * n,
ANGLE t1' _
MANUFACTURER 't ,1 �I ,
RECOMMENDED
INSTALLATION1:1 CD
ANGLE±1' -I
i
-41
CP
FIGURE 3—TYPE C SLAB SUPPORT APPLICATION FIGURE 4—TYPE D TENSION ANCHOR APPLICATION
Page 18 of 24
• ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358)
S
X
STRUCTURE STRUCTURE STRUCTURE - STRUCTURE
ECCENTRICITY INTERNAL - INTERNAL = - INTERNAL
a SHEAR e < SHEAR 4 SHEAR e
MOMENT MOMENT ` MOMENT
(TORSION) (TORSION) (TORSION)
74_
BRACKET /
ECCEN-RICITY `�'/ium
T CENTROID OF I CENTROID OF
T CENTROID OF
CONCRETE CONCRETE CONCRETE
COMPRESSION COMPRESSION COMPRESSION
1 AREA I AREA 1 AREA
litI
(a) Rigid Shaft (b) Flexible Shaft (c) Combined Stiffness
FIGURE 5—TYPE A BRACKET FREE BODY DIAGRAMS
i—BRACKUT r PIER SHAFT CALIBRATED PRESSURE GAGE
REFERENCE BEAM
TO HYD. PUMP
, /
DIAL GAGE
a� 7/ DUAL ACTION
2 HYDRAULIC CYLINDER
a ✓;- { STEEL MOUNTS
3Wx3Wx3W CONCRETE BLOCK STEEL -BEAM
W=BRACKET WIDTH
For SI: 1 inch=25.4 mm.
FIGURE 6—TYPE A BRACKET EXAMPLE LABORATORY TEST SET-UP
Page 19 of 24
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358)
PIER SHAFT
BRACKET CALIBRATED PRESSURE GAGE
5-0' 0—TO HYD.PUMP
STEEL MOUNTS 7 DUAL ACTION
HYDRAULIC CYLINDER
STEEL MOUNTS
3Wx3Wx3W CONCRETE BLOCK STEEL I—BEAM
W=BRACKET WIDTH
OR OTHER STRUCTURE PER MANUF
(AXIAL LOAD SET—UP)
STEEL GUIDE
ROLLER SUPPORT
CALIBRATED PRESSURE GAGE
BRACKET TO HYD. PUMP
�� PIER SHAFT
STEEL MOUNTS / �o
p•■%i�i
A
CONCRETE BLOCK SIZE& STEEL I—BEAM
REINFORCE PER MANUF. DUAL ACTION
OR OTHER STRUCTURE PER MANUF HYDRAULIC CYLINDER
(LATERAL LOAD SET—UP)
FIGURE 7—TYPE B BRACKET EXAMPLE LABORATORY TEST SET-UP
CALIBRATED PRESSURE GAGE
HYDRAULIC CYLINDER
,( TG HYD. PUMP
STEEL I—BEAM
PIER SHAFT ' REFERENCE BEAM
DAL GAGE
STEEL I—BEAM �•
—i i i-iiiiii-ii- i i H i i_i i i=i�-_�i_is i-�� -i�iit=1��-
— _ �-111 ANCHOR PILE
BRACKET
GROUT
CONCRETE SLAB EQUAL FLEXIBLE ,AIR BAG
TO MFGR. RECOMMENDED
PIER SPACING
For SI: 1 inch=25.4 mm.
FIGURE 8—TYPE C BRACKET EXAMPLE LABORATORY TEST SET-UP
Page 20 of 24
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358)
PIER SHAFT
REFERENCE BEAM
5'-0' CALIBRATED PRESSURE GAGE
TO HYD. PUMP
DIAL GAGE V
DUAL ACTION
MFGR. HYDRAULIC CYLINDER
RECOMMENDED j STEEL MOUNTS
ANGLE t1' _-46 A
CONCRETE BLOCK
STEEL I-BEAM
STEEL MOUNTS
For SI: 1 inch=25.4 mm.
FIGURE 9—TYPE D BRACKET EXAMPLE TEST SET-UP
MIN 3'-0", OR
12X SHAFT DIAMETER, ANGLE MEASURING PLATE
WHICHEVER IS GREATER
STEEL MOUNTS % TORQUE MOTOR
irk' STEEL MOUNTS
STEEL I-BEAM
HELIX
PIER SHAFT COUPLING
For SI: 1 inch=25.4 mm.
FIGURE 10—SHAFT TORSION EXAMPLE LABORATORY TEST SET-UP
HYDRAULIC CYLINDER
CALIBRATED PRESSURE GAGE
STEEL I-BEAM
TO HYD. PUMP
STEEL MOUNTS
/// /% ,�-tipIll
, PIER SHAFT
jupp
SIMPLE SUPPORT
STEEL I-BEAM A' u b.
DTA
�; � ��//////////��Ii����Ii����/// SIMPLE SUPPORT
COUPLING DIAL GAGE
MIN 3'-0", OR
12X SHAFT DIAMETER,
WHICHEVER IS GREATER REFERENCE BEAM
FIGURE 11—SHAFT BENDING EXAMPLE LABORATORY TEST SET-UP
Page 21 of 24
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358)
r-REFERENCE BEAM
DIAL GAGE
HYDRAULIC CYLINDER
IIIMt
o
m UNSUPPORTED END
U)
z
I-
CYLJ
MAXIMUM POSSIBLE
NUMBER OF COUPLINGS
lil
h_
PIER SHAFT
0
I-
U
z I FIXED END
Iri
STEEL MOUNTS
STEEL I-BEAM
FIGURE 12—COUPLING RIGIDITY EXAMPLE LABORATORY TEST SET-UP
HYDRAULIC CYLINDER
CALIBRATED PRESSURE GAGE
STEEL I-BEAM
V- TO HYD. PUMP
REFERENCE BEAM / PIER SHAFT WTH HELIX
DIAL GAGE 111, ��.
/�f lI, A STEEL MOUNTS
5 POINT ADJUSTABLE MANDRILL PLATE
STEEL I-BEAM
Rm=Y:(Rb+Rs)
FIGURE 13—HELIX EXAMPLE LABORATORY TEST SET-UP
Page 22 of 24
•
• ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358)
APPENDIX A
REQUIREMENTS UNDER THE 2024,2021,2018,2015,2012,2009 AND 2006 IRC
Appendix A summarizes amendments to the criteria that supersede applicable portions to Sections 1.0 to 6.0 of the criteria for
evaluation under the 2024,2021,2018,2015,2012,2009 and 2006 International Residential Code®(IRC).The revisions herein
reflect the difference in content from Sections 1.0 to 6.0 of this criteria. The numbering system within Appendix A uses the
number that corresponds to the Section in the criteria where that change would be located.The reason for the development of
Appendix A in the acceptance criteria is to provide requirements for the evaluation of helical pile systems and devices used as
alternates to the foundation provisions in Chapter 4 of the IRC.
1.2 Scope: This criteria provides methods to establish the allowable load and deformation capacities of helical pile systems
and devices used to resist axial compression, axial tension or lateral loads. This appendix to the criteria applies to helical pile
systems and devices as defined in Section 1.4 of the criteria.
1.2.1 This criteria appendix is limited to evaluation of helical pile systems and devices for use under the following conditions:
For use as an alternate foundation system supporting light-frame construction, exterior porch deck, elevated walkway and
stairway construction, and accessory structures assigned to Seismic Design Categories (SDCs)A, B and C as defined in the
IRC, Unless additional requirements in accordance with Section 3.14 of this criteria are satisfied for SDCs Do, Di, D2 and E in
accordance with IRC.
1.3.1 2024, 2021,2018, 2015, 2012,2009 and 2006 International Residential Code®(IRC), International Code Council
3.5 P4 Soil Capacity:The P4 soil capacity for axial loading is the least allowable axial load that can be sustained by the soil
or bedrock bearing stratum supporting the helical pile,as determined by a registered design professional based on site-specific
conditions through installation torque correlations in accordance with Section 3.13.1 of the criteria and based on the ultimate
bearing capacity, as determined by accepted geotechnical engineering methods or load tests. See Section 3.6 of Appendix A
for the P4 soil capacity for lateral loading.
3.6 Determination of Allowable Design Capacities: In accordance with Section 3.7, the allowable design capacities of
helical pile elements, P1 and P2, shall be evaluated based on Conventional Design with no testing required, Special Analysis
with verification tests, or solely on tests. For Type A brackets allowable design capacities shall be based on either conventional
design or direct measurement only.All load tests shall be conducted in accordance with Section 4.0.The allowable capacity P3
shall be determined through load testing only as prescribed in Section 3.12 of the criteria.The allowable axial capacity P4 shall
be determined per Section 3.5 of Appendix A.The allowable lateral load capacity,P4,shall be determined by a registered design
professional or by lateral load testing in accordance with Section 3.13.2 of the criteria.
3.14 Special Seismic Requirements:
3.14.1 General: For optional evaluation for use in structures assigned to SDCs Do, Di,D2 and E,the helical pile systems and
helical pile devices shall comply with the additional requirements prescribed in Sections 3.14.2 and 3.14.3 of the criteria.
6.0 EVALUATION REPORT REQUIREMENTS
6.1 General:The evaluation report shall include a description of the helical pile system and device,typical applications, and
limitations.The evaluation report shall state that:
(1) The system and device shall be limited to support of structures in IRC Seismic Design Categories A, B, and C. If
compliance with the additional requirements of Section 3.14 is established, then helical pile systems and helical pile devices
supporting structures in Seismic Design Categories D, Do, Di D2 and E can be stated. Otherwise, a statement indicating that
the use of the system and device to support structures located in Seismic Design Category D, Do, Di, D2 or E, is outside the
scope of this evaluation report
6.3 Shafts: Shaft capacities shall be tabulated for each size of shaft for the conditions of being braced or unbraced in soft
and firm soils as applicable. Helical pile shafts fully embedded into soil conditions defined in IRC Table R401.4.1 shall be
deemed adequate to prevent buckling of the shaft. The evaluation report shall state that the shaft capacity of helical piles in air,
water or fluid soils shall be determined by a registered design professional. For evaluation reports including provisions for lateral
resistance, the structural properties of the shaft shall be provided including gross area, section modulus, modulus of elasticity,
maximum allowable bending moment,and maximum allowable shear.
6.5 Soil Capacity:A soils capacity-to-torque ratio shall be listed in the evaluation report along with the equations set forth in
this acceptance criteria. The evaluation report shall indicate that the soil capacity, as determined by registered design
professional, shall be based on the lowest value achieved through site-specific geotechnical information. If site specific
geotechnical information is not available,the minimum safety factor to establish soil capacity based on torque correlations shall
be increased to 2.5. For lateral soil resistance,the evaluation report shall contain a table of capacities for all soil types including
soil classifications based on geotechnical investigations conducted on the test site used in the lateral load testing.The evaluation
report shall state that lateral soil resistance, if necessary for the project, shall be determined by loading testing or a registered
design professional for soil conditions that differ from those shown in the table.
6.7 Design: The evaluation report shall state that the registered design professional shall determine the helical pile system
and devices, including the bracket, used as a foundation element and the applied loads shall not exceed the capacity of the
helical pile system. The evaluation report shall state that the registered design professional shall determine the design forces
in accordance with IRC R301.
Page 23 of 24
ACCEPTANCE CRITERIA FOR HELICAL PILE SYSTEMS AND DEVICES(AC358) •
6.8 Soils Condition:The evaluation report shall indicate that soil tests shall be as required in IRC Section R401.4 or in lieu
of a complete geotechnical evaluation, the soil capacity shall be based on the torque correlation provisions in Section 3.13 of
AC358, subject to the limitations in Section 6.5 of Appendix. The registered design professional shall determine that the soil
condition will not increase the potential for pile corrosion based on the soil parameters established in Section 6.1 of the criteria.
Page 24 of 24