This standard specifies the classification and mark, requirements, test methods, inspection rules, marking, product instructions, packaging, transportation and storage of mechanical anchors with concrete as substrate.
This standard is applicable to metal anchors anchored on cracked or non-cracked concrete with compressive strength of 25 MPa to 60 MPa.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB 175 Common Portland Cement
GB/T 193 General Purpose Metric Screw Threads - General Plan
GB/T 196 General Purpose Metric Screw Threads - Basic Dimensions
GB/T 197 General Purpose Metric Screw Threads - Tolerances
GB/T 699 Quality Carbon Structure Steels
GB/T 700 Carbon Structural Steels
GB/T 1220 Stainless Steel Bar
GB/T 3077 Alloy Structure Steels
GB/T 3098.1 Mechanical Properties of Fasteners - Bolts, Screws and Studs
GB/T 3098.2 Mechanical Properties of Fasteners - Nuts
GB/T 3098.6 Mechanical Properties of Fasteners - Stainless Steel Bolts, Screws and Studs
GB/T 3098.15 Mechanical Properties of Fasteners - Stainless Steel Nuts
GB/T 4237 Hot Rolled Stainless Steel Plate, Sheet and Strip
GB/T 5267.1 Fasteners - Electroplated Coatings
GB/T 5267.3 Fasteners - Hot Dip Galvanized Coatings
GB/T 6335.1 Rotary and Rotary Impact Masonry Drill Bits with Hardmetal Tips Part1: Dimensions
GB/T 9799 Metallic and Other Inorganic Coatings - Electroplated Coatings of Zinc with Supplementary Treatments on Iron or Steel
GB/T 13912 Metallic Coatings - Hot Dip Galvanized Coatings on Fabricated Iron and Steel Articles - Specifications and Test Methods
GB/T 14684 Sand for Construction
GB/T 14685 Pebble and Crushed Stone for Construction
GB/T 14975 Seamless Stainless Steel Tubes for Structure
GB/T 19292.2 Corrosion of Metals and Alloys - Corrosivity of Atmospheres - Guiding Values for the Corrosivity Categories
GB/T 19355.1 Zinc Coatings - Guidelines and Recommendations for the Protection Against Corrosion of Iron and Steel in Structures - Part 1: General Principles of Design and Corrosion Resistance
GB/T 19355.2 Zinc Coatings - Guidelines and Recommendations for the Protection Against Corrosion of Iron and Steel in Structures - Part 2: Hot Dip Galvanizing
GB/T 19355.3 Zinc Coatings - Guidelines and Recommendations for the Protection Against Corrosion of Iron and Steel in Structures - Part 3: Sherardizing
GB/T 25672 Hammer Drills and Shell Hammer Drills
GB/T 31303 Austenitic-Ferritic Duplex Stainless Steel Bars
JB/T 5067 Sherardizing of Iron and Steel Articles
3 Terminologies, Definitions and Symbols
For the purposes of this document, the following terminologies, definitions and symbols apply.
3.1 Terminologies
3.1.1
Mechanical anchors
Component that is anchored on a concrete substrate by virtue of friction or locking effect between the anchor and the borehole, with the main stressed members consisting of fasteners (screw, nut, gasket), conical heads and expansion parts (expansion bushing or expansion sheet) that are made of metallic material.
3.1.2
Expansion anchors
Anchors with friction, which is generated when expansion part is applied with torque or tapped and therefore squeezes the hole wall, as the main anchorage force. See Appendix A, Figure A.1.
3.1.3
Undercut anchors
Anchors with mechanical engaging force, which is generated by locking wedge formed by expansion part which is embedded into the hole expanded by special die bit or hard blade on the anchor expansion part at certain depth of the straight hole when applied with torque or tapped, as the main anchorage force.
3.1.3.1
Pre-drilled undercut anchors
Undercut anchors which is installed after hole expansion is carried out with special die bit. See Appendix A, Figure A.2.
3.1.3.2
Self-cutting undercut anchors
Undercut anchors with its expansion part having hard blade through which hole expansion and expansion part embedding are completed during anchor installation. See Appendix A, Figures A.3 and A.4.
3.1.3.3
Double-wedge anchors
Anchor bolts with upper and lower anchorage points, among which the latter is the undercut locking wedge and main anchorage point, and the former is locking wedge or expansion point and auxiliary anchorage point. See Appendix A, Figure A.5.
3.1.4
Screw anchors
Anchor bolts, when are screwed into the drilled hole, cut and embed into the embedding hole wall through self-contained hard threads. See Appendix A, Figure A.6.
3.1.5
Installation torque
Tighten torque required to install anchors.
3.1.6
Installation displacement
Displacement required to install anchors through tapping.
3.1.7
Torque control
Anchor installation method by which torque is applied on anchor screws, nuts or bushings.
3.1.8
Displacement control
Anchor installation method by which anchor conical head or bushing is tapped.
3.1.9
Anchorage zone
Zone in the concrete within which the anchor transmits external load.
3.1.10
Concrete cone failure
Cone failure of concrete formed with anchor as the axis in the anchorage zone under the action of tension. See Appendix A, Figure A.7.
3.1.11
Anchor pull-out failure
Failure of concrete formed due to anchor, under the action of tension, slides towards the concrete surface and finally is pulled out, all or partially, from the concrete, or causes failure at shallow position on the concrete that is similar as the concrete cone failure. See Appendix A, Figure A.8.
3.1.12
Anchor steel failure
Failure of the metal component of the anchor under the action of tension or shear. See Appendix A, Figure A.9.
3.1.13
Concrete splitting failure
Failure of concrete in the form of crack along the vertical line of a single anchor axis or along the common vertical line of multiple anchor axes under the action of tension. See Appendix A, Figure A.10.
3.1.14
Concrete edge failure
Semi-conical fracture formed at concrete edge under the action of tension or that formed at the concrete edge in the shear direction under the action of shearing force. See Appendix A, Figure A.10.
3.1.15
Reference test
Mechanical property test conducted by drilling holes on the dry concrete with specified strength by using drill with diameter of dm, edge distance and interval of holes not less than 2hef and 4hef respectively, and anchor installed according to the requirements of the product instructions. The test data is usually used as a reference for other tests for comparison.
3.1.16
Coefficient of radial force
Ratio of the radial expansion force to the axial tensile force of the anchor under the action of tension.
3.2 Symbols
As - the nominal sectional area of the anchor screw part with failure due to tension, mm2;
Asv - the nominal sectional area of the anchor part under shearing force, mm2;
Asv,b - the screw nominal sectional area at the anchor part under shearing force, mm2;
Asv, s - the bushing nominal sectional area at the anchor part under shearing force, mm2;
c - the coefficient (constant);
dm - the medium diameter of the test drill bit, see Appendix B, mm;
dmax - the maximum diameter of the drill bit for test, see Appendix B, mm;
dmin - the minimum diameter of the drill bit for test, see Appendix B, mm;
fcu - the measured value of compressive strength of concrete cube, MPa;
hef - the effective anchorage depth, i.e., the distance from the concrete surface to the anchorage point, see A.1, mm;
N - the tensile load, N;
N1 - the slip load, N;
NRk - the standard value of tensile capacity, N;
NRu,m - the average of tensile capacity, N;
NRu, s - the tensile capacity of anchor screw steel, N;
Rm,min - the minimum tensile strength of anchor screw steel, MPa;
Rm,s - the tensile strength of bushing steel, MPa;
T - the measured value of the torque limit, N?m;
Tinst - the anchor installation torque required in the product instructions, N?m;
VRu, s - the shear capacity of anchor steel, N;
γmin - the minimum value of the slip coefficient in the test sample;
Δw - the crack width, mm;
Δw1 - the upper limit of the relative crack width, mm;
Δw2 - the lower limit of the relative crack width, mm;
δm - the displacement of the anchor during the seismic performance special test cycle, mm;
η - the radial force coefficient;
vN - the coefficient of variation of tensile capacity;
vV - the coefficient of variation of shear capacity;
vβ - the coefficient of variation of tensile stiffness.
