Product Technical Guides : US-EN Anchor Fastening - August 2021 | Page 25

3.1.9 ALLOWABLE STRESS DESIGN ( ASD )
ALLOWABLE STRESS DESIGN ( ASD ) TERMINOLOGY
A nom
= nominal bolt cross sectional area , in . 2 ( mm 2 )
A sl
= cross sectional area of anchor sleeve , in . 2 ( mm 2 )
A st
= tensile stress area of threaded part , in . 2 ( mm 2 ) c
= distance from anchor centerline to the closest free edge of base material , in . ( mm ) c cr
= critical edge distance , in . ( mm ) c min
= minimum edge distance , in . ( mm ) d = anchor bolt diameter ( shank diameter ), in . ( mm )
d bit
= nominal drill bit diameter , in . ( mm ) d h
= diameter of clearance hole in attachment ( e . g . baseplate ), in . ( mm ) d nom
= nominal anchor diameter , in . ( mm ) d o
= anchor outside diameter ( O . D .), in . ( mm ) d w
= washer diameter , in . ( mm ) ƒ A
ƒ c
= adjustment factor for anchor spacing
= concrete compressive strength as measured by testing of cylinders , psi ( MPa ) ƒ ' c
= specified concrete compressive strength , psi ( MPa ) ƒ RN
= adjustment factor for edge distance , tension loading ƒ RV1
ƒ RV2
ƒ RV3
= adjustment factor for edge distance , shear loading perpendicular and towards free edge
= adjustment factor for edge distance , shear loading parallel to free edge
= adjustment factor for edge distance , shear loading perpendicular and away from free edge f y
= specified reinforcing bar yield strength , psi ( MPa )
F y
= specified bolt minimum yield strength , psi ( MPa )
F u
= specified bolt minimum ultimate strength , psi ( MPa ) h
= thickness of member in which anchor is embedded as measured parallel to anchor axis , in . ( mm ) h ef
= effective anchor embedment depth , in . ( mm ) h nom
= distance between base material surface and bottom of anchor ( prior to setting is applicable ), in . ( mm ) h o
= depth of full diameter hole in base material , in . ( mm )
l = anchor embedded length , in . ( mm )
l th
= anchor useable thread length , in . ( mm )
M uM , 5 %
= characteristic flexural resistance of anchor bolt ( 5 % fractile ) , in-lb ( N · m )
N allow
= allowable tension load , lb ( kN )
N d
= design tension load ( unfactored ), lb ( kN )
N rec
= recommended tension load , lb ( kN ) s = anchor axial spacing , in . ( mm )
s cr
s min
= critical spacing between adjacent loaded anchors , in . ( mm )
= minimum spacing between adjacent loaded anchors , in . ( mm )
S = elastic section modulus of anchor bolt , in . 3 ( mm 3 )
s W
= width of anchor nut across flats , in . ( mm ) t fix
= maximum thickness of attachment ( e . g . baseplate ) to be fastened , in . ( mm )
T inst
= recommended anchor installation torque , ft-lb ( N · m )
T max
= maximum tightening torque , ft-lb ( N · m )
V allow
= allowable shear load ( based on mean value from tests and a global safety factor ), lb ( kN )
V d
= design shear load ( unfactored ), lb ( kN )
V rec
= recommended shear load , lb ( kN )
GENERAL REQUIREMENTS AND RECOMMENDED LOADS
In accordance with the general ASD principles , the design of anchors must satisfy the following conditions :
N service
≤ N rec
V service
≤ V rec whereby N service and V service are the service tension and shear loads resulting from the governing load combinations ( i . e . ASCE 7-10 ) and N rec and V rec are the recommended allowable loads for an anchor or a group of anchors .
The ASD method is currently referenced in masonry-related ICC-ES AC01 , AC58 , AC60 , and AC106 . h min
= minimum member thickness , in . ( mm )
Anchor Fastening Technical Guide Edition 22 | 3.0 ANCHORING SYSTEMS | 3.1 ANCHOR PRINCIPLES AND DESIGN Hilti , Inc . 1-800-879-8000 | en español 1-800-879-5000 | www . hilti . com | Hilti ( Canada ) Corporation | www . hilti . ca | 1-800-363-4458
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