ANSI EP486.3-2017 Shallow Post and Pier Foundation Design.pdf

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1、 ANSI/ASAE EP486.3 SEP2017 Shallow Post and Pier Foundation Design American Society of Agricultural and Biological Engineers ASABE is a professional and technical organization, of members worldwide, who are dedicated to advancement of engineering applicable to agricultural, food, and biological syst

2、ems. ASABE Standards are consensus documents developed and adopted by the American Society of Agricultural and Biological Engineers to meet standardization needs within the scope of the Society; principally agricultural field equipment, farmstead equipment, structures, soil and water resource manage

3、ment, turf and landscape equipment, forest engineering, food and process engineering, electric power applications, plant and animal environment, and waste management. NOTE: ASABE Standards, Engineering Practices, and Data are informational and advisory only. Their use by anyone engaged in industry o

4、r trade is entirely voluntary. The ASABE assumes no responsibility for results attributable to the application of ASABE Standards, Engineering Practices, and Data. Conformity does not ensure compliance with applicable ordinances, laws and regulations. Prospective users are responsible for protecting

5、 themselves against liability for infringement of patents. ASABE Standards, Engineering Practices, and Data initially approved prior to the society name change in July of 2005 are designated as “ASAE“, regardless of the revision approval date. Newly developed Standards, Engineering Practices and Dat

6、a approved after July of 2005 are designated as “ASABE“. Standards designated as “ANSI“ are American National Standards as are all ISO adoptions published by ASABE. Adoption as an American National Standard requires verification by ANSI that the requirements for due process, consensus, and other cri

7、teria for approval have been met by ASABE. Consensus is established when, in the judgment of the ANSI Board of Standards Review, substantial agreement has been reached by directly and materially affected interests. Substantial agreement means much more than a simple majority, but not necessarily una

8、nimity. Consensus requires that all views and objections be considered, and that a concerted effort be made toward their resolution. CAUTION NOTICE: ASABE and ANSI standards may be revised or withdrawn at any time. Additionally, procedures of ASABE require that action be taken periodically to reaffi

9、rm, revise, or withdraw each standard. Copyright American Society of Agricultural and Biological Engineers. All rights reserved. ASABE, 2950 Niles Road, St. Joseph, Ml 49085-9659, USA, phone 269-429-0300, fax 269-429-3852, hqasabe.org S T A N D A R D ANSI/ASAE EP486.3 SEP2017 Copyright American Soci

10、ety of Agricultural and Biological Engineers 1 ANSI/ASAE EP486.3 SEP2017 Revision approved 2017 as an American National Standard Shallow Post and Pier Foundation Design Developed by the ASAE Post and Pole Foundation Subcommittee; approved by the Structures and Environment Division Standards Committe

11、e; adopted by ASAE March 1991; revised editorially December 1992; reaffirmed December 1995, December 1996, December 1997, December 1998; revised December 1999; approved as an American National Standard October 2000; reaffirmed by ASAE February 2005;reaffirmed by ANSI March 2005; periodic review exte

12、nsion for two years approved October 2009; revised October 2012; revision approved by ANSI October 2012; editorial revision June 2013; reaffirmed by ASABE and ANSI December 2016; revised ASABE and approved by ANSI September 2017. Keywords: Foundation, Post, Shallow, Structures 1 Purpose and scope 1.

13、1 Purpose. The purpose of this Engineering Practice is to present a procedure for determining the adequacy of shallow, isolated post and pier foundations in resisting applied structural loads. This Engineering Practice will help ensure that soil and backfill are not overloaded, foundation elements h

14、ave adequate strength, frost heave is minimized, and lateral movements are not excessive. 1.2 Scope. This engineering practice contains safety factors and other provisions for allowable stress design (ASD) which is also known as working stress design, and for load and resistance factor design (LRFD)

15、 which is also known as strength design. It also contains properties and procedures for modeling soil deformation for use in structural building frame analyses. 1.2.1 Limitations. Application of this Engineering Practice is limited to post and pier foundations with the following characteristics: ver

16、tically installed in relatively level terrain; concentrically-loaded footings; minimum post or pier foundation spacing equal to the greater of 4.5 times the maximum dimension of the post/pier cross-section, or three times the maximum dimension of a footing or attached collar. 2 Normative references

17、The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies unless noted. For undated references, the latest approved edition of the referenced document (including any amendments) applies. 2.1 Structural design speci

18、fications ACI 318, Building Code Requirements for Structural Concrete and Commentary ANSI/AWC NDS, National Design Specification (NDS) for Wood Construction with Commentary ANSI/ASAE EP484, Diaphragm Design of Metal-Clad, Wood-Frame Rectangular Buildings ANSI/ASAE EP559, Design Requirements and Bend

19、ing Properties for Mechanically Laminated-Wood Assemblies ASCE/SEI 7-10, Minimum Design Loads for Buildings and Other Structures ANSI/ASAE EP486.3 SEP2017 Copyright American Society of Agricultural and Biological Engineers 2 SEI/ASCE 32, Design and Construction of Frost-Protected Shallow Foundations

20、 2.2 Laboratory soil testing standards ASTM D422, Standard Test Method for Particle-Size Analysis of Soils ASTM D854, Standard Test Methods for Specific Gravity of Soil Solids by Water Pycnometer ASTM D2166, Standard Test Method for Unconfined Compressive Strength of Cohesive Soil ASTM D2435, Standa

21、rd Test Methods for One-Dimensional Consolidation Properties of Soils Using Incremental Loading ASTM D2487, Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System) ASTM D2850, Standard Test Method for Unconsolidated-Undrained Triaxial Compression T

22、est on Cohesive Soils ASTM D3080, Standard Test Method for Direct Shear Test of Soils Under Consolidated Drained Conditions ASTM D4318, Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils ASTM D4643, Test Method for Determination of Water (Moisture) Content of Soil b

23、y Microwave Oven Heating ASTM D4767, Standard Test Method for Consolidated Undrained Triaxial Compression Test for Cohesive Soils ASTM D7181, Standard Test Method for Consolidated Drained Triaxial Compression Test for Soils 2.3. In-situ soil testing standards ASTM D1586, Standard Test Method for Sta

24、ndard Penetration Test (SPT) and Split-Barrel Sampling of Soils ASTM D2573, Standard Test Method for Field Vane Shear Test in Cohesive Soil ASTM D3441, Standard Test Method for Mechanical Cone Penetration Tests of Soil ASTM D4719, Standard Test Method for Prebored Pressuremeter Testing in Soils ASTM

25、 D1194, Standard Test Method for Bearing Capacity of Soil for Static Load and Spread Footings (withdrawn 2003) ASTM D4750, Standard Test Method for Determining Subsurface Liquid Levels in a Borehole or Monitoring Well (Observation Well) ASTM D5778, Standard Test Method for Electronic Friction Cone a

26、nd Piezocone Penetration Testing of Soils 2.4 Preservative-treated wood standard AWPA U1, Use Category System: User Specification for Treated Wood 2.5 Nomenclature standard ANSI/ASABE S618, Post-Frame Building System Nomenclature 3 Definitions 3.1 Foundation types and components 3.1.1 backfill: Mate

27、rial filling the excavation around a post or pier foundation. See Figure 5. 3.1.2 collar: Foundation component attached to a post or pier, and that moves with it to resist lateral and vertical loads. See Figure 5. ANSI/ASAE EP486.3 SEP2017 Copyright American Society of Agricultural and Biological En

28、gineers 3 3.1.3 driven pier or post: A pier or post that is pounded or turned into the ground. A pier or post foundation not requiring prior soil excavation. Also referred to as a displacement pier or post. See Figure 2. 3.1.4 footing: Foundation component at the base of a post or pier that provides

29、 resistance to vertical downward forces. When properly attached to the post/pier, a footing aids in the resistance of lateral and vertical uplift forces, and embedment depth is measured to the base of the footing instead of to the top of the footing. See Figures 1 through 5. 3.1.5 helical pier: A pi

30、er comprised of a steel pipe or tubing with an attached helix or helices. See Figure 2. Helices are also known as auger flighting. A helical pier is a type of driven pier that is turned into the soil in a manner that minimizes soil movement/displacement. 3.1.6 pedestal: A relatively short column tha

31、t can support vertical forces, but is not designed to transmit horizontal shear, and bending moments. This engineering practice is not applicable to the design of pedestals. 3.1.7 pier: A relatively short column partly embedded in the soil to provide lateral and vertical support for a building or ot

32、her structure. Piers include members of any material with assigned structural properties such as solid or laminated wood, steel, or concrete. Piers differ from embedded posts in that they seldom extend above the lowest horizontal framing element in a structure, and when they do, it is often only a f

33、ew centimeters. See Figures 2 through 4. 3.1.8 pier foundation: An assembly consisting of a pier and all below-grade elements, which may include a footing, uplift resistance system, and collar. See Figure 3. 3.1.9 pile: A relatively long and slender column driven, screwed, jacked, vibrated, drilled

34、or otherwise installed into soil to provide lateral and vertical support for a structure. Generally used to carry loads through weak layers of soil to those capable of supporting such loads. This engineering practice is not applicable to the design of piles. 3.1.10 pole: A round post. 3.1.11 post: A

35、 structural column that functions as a major foundation element by providing lateral and vertical support for a structure when it is embedded in the soil. Posts include members of any material with assigned structural properties such as solid or laminated wood, steel, or concrete. See Figures 1 and

36、5. 3.1.12 post foundation: An assembly consisting of an embedded post and all below-grade elements, which may include a footing, uplift resistance system, and collar. See Figure 1. 3.1.13 screw anchor: A helical pier primarily designed to handle uplift or tension forces. 3.1.14 shallow foundation: A

37、 foundation for which deformation under load is small, so foundation movement approximates rigid body motion. Foundation deformation is kept small by selection of foundation depth, d, and post/pier bending stiffness, Ep Ip. 3.1.15 uplift resistance system: Elements attached to an embedded post or pi

38、er, generally near the base, to increase the uplift resistance of a foundation system. See Figures 1 through 5. 3.2 Foundation geometry and constraints 3.2.1 constrained post (or pier): A post or pier foundation that is restrained from significant horizontal movement at the ground surface, typically

39、 by a concrete slab. 3.2.2 foundation depth, dF: Vertical distance from the ground surface to the bottom of a post or pier foundation. Typically the vertical distance from the ground surface to the base of the footing. 3.2.3 non-constrained post (or pier): A post or pier foundation that is not restr

40、ained from moving horizontally at or above the ground surface. ANSI/ASAE EP486.3 SEP2017 Copyright American Society of Agricultural and Biological Engineers 4 3.2.4 post (or pier) embedment depth, d: Vertical distance from the ground surface to the bottom of the embedded post or pier. Includes the t

41、hickness of the footing when the footing is rigidly attached to the post/pier or is cast integrally with the post/pier. 3.2.5 post (or pier) width, B: The cross-sectional dimension that is perpendicular to the direction of lateral post/pier movement. This width defines the area of contact between th

42、e foundation and soil that resists lateral post/pier movement. The width of a round post or pier is its diameter. 3.3 Material properties and characteristics 3.3.1 cohesion of soil, c: Component of soil shear strength due to cementation or bonding at particle contacts resulting from ionic bonds, hyd

43、rogen bonds, and gravitational attraction. 3.3.2 controlled low-strength material (CLSM): A self-leveling and self-compacting, cementitious material with an unconfined compressive strength of 8 MPa (1200 psi) or less. Other terms used to describe controlled low-strength material (CLSM) include flowa

44、ble fill, unshrinkable fill, controlled density fill, flowable mortar, flowable fly ash, fly ash slurry, plastic soil-cement and soil-cement slurry. 3.3.3 constant of horizontal subgrade reaction, nh: Soil property used in the calculation of horizontal soil stiffness. When divided by post/pier width

45、 b, the constant of horizontal subgrade reaction establishes the rate at which the modulus of horizontal subgrade reaction increases with depth. 3.3.4 dry bulk density of soil, D: Oven-dried mass of a soil divided by its in-situ volume. Also known as dry unit weight. 3.3.5 effective stress: Net stre

46、ss across points of contact of soil particles, generally considered as equivalent to the total stress minus the pore water pressure. 3.3.6 frost heave: Surface distortion caused by volume expansion within the soil when water freezes and ice lenses form. 3.3.7 moist bulk density of soil, : Mass of a

47、soil divided by its in-situ volume. Also known as wet unit weight. 3.3.8 Poissons ratio, : Transverse (lateral) strain divided by the corresponding axial (longitudinal) strain that occurs when a uniformly distributed axial load is applied to a soil sample whose transverse expansion is not restricted

48、 during load application. 3.3.9 soil friction angle, : Slope angle of Mohr-Coulomb shear strength criterion for soils, where shear strength = tan + c. 3.3.10 swelling soil: A soil material, particularly clays, that exhibit expansion with increasing moisture content, and shrinkage with decreasing moi

49、sture content. Also referred to as an expansive soil. 3.3.11 total stress: Total pressure exerted in any direction by both soil and water. 3.3.12 undrained shear strength, SU: Shear strength of soil sheared such that pore water pressure is not allowed to dissipate (i.e., undrained condition). Shear strength criterion typically used for short-term loading of soil with significant clay content. 3.3.13 Youngs modulus for soil, ES: Uniaxial compressive stress divided by the corresponding uniaxial strain of a soil sample whose transverse (lat