Anchor Fastening Technical Guide , Edition 22
Table 91 — Suggested embedment and edge distance ( see figure below ) based on ACI 318 Chapter 17 to develop 125 % of
f y in Grade 60 wall / column starter bars in a linear array with bar spacing = 24 inches - SDC A and B only 1 , 2 , 3 , 4 , 5 , 6 ƒ ' c = 2,500 psi ƒ ' c
= 3,000 psi ƒ ' c = 4,000 psi ƒ ' c
= 6,000 psi
Rebar size
# 3
Linear spacing s in .
Effective embed .
h ef in .
Cond . I
Minimum edge dist
c a , min in .
Cond . II
Effective embed .
h ef in .
Cond . I
Minimum edge dist
c a , min in .
Cond . II
Effective embed .
h ef in .
Minimum edge dist
c a , min in .
Effective embed .
h ef in .
Minimum edge dist
c a , min in .
7 18 8 7 18 7 7 18 7 7 17 6 # 4 10 25 12 10 25 11 9 24 10 9 24 9 # 5 24 13 33 19 12 31 17 12 30 15 11 29 12 # 6 21 55 32 19 49 28 15 40 23 13 35 18 # 7 32 83 47 28 75 42 23 62 35 18 48 26
1 h ef is the calculated bar embedment based on uncracked bond and concrete breakout strengths using equations in section 3.1.14 to develop 125 % of nominal bar yield . Shaded embedment values exceed 20 bar diameters . For non-tabulated rebar sizes , design per development length provisions is recommended . The particular assumptions used for the application of anchor theory to bar development ( e . g ., bar yield and bond strength values ) are a matter of engineering judgment and will in part depend on the specific circumstances of the design . For embedments corresponding to nominal yield ( i . e ., no overstrength ) multiply the tabulated h ef values by 0.86 .
2 c a is the minimum edge distance ( from bar centerline ) associated with the tabulated embedments and s = 24 in . Refer to sec . 3.1.14 for applicability of edge distance “ Condition I ” and
“ Condition II .” 3 Applicable for hammer-drilled holes . For rock-drilled and core-drilled holes , contact Hilti . 4 Values determined with bond stresses , k-factors and strength reduction factors taken from ESR- ] Tables 12 and 13 assuming dry concrete conditions where concrete temperatures will not exceed a maximum short-term temperature of 130 ° F ( 55 ° C ) and long-term temperature of 110 ° F ( 43 ° C ). Bond stresses are for static ( non-seismic ) loading conditions . 5 Values are for normal weight concrete . For lightweight concrete contact Hilti . 6 Refer to the Hilti North America Post-Installed Reinforcing Bar Guide for detailed explanation , background information , and design examples . See Hilti Instructions for Use ( IFU ) for specific installation requirements .
Cond . I
Cond . II
Cond . I
Cond . II
3.2.2
≥ c a , min s = 24 in . s = 24 in .
( N ) ≥ c a , min h ef
SECTION ( E )
Bars in linear array
SECTION Illustration of Table 91 dimensions
PLAN
Anchor Fastening Technical Guide Edition 22 | 3.0 ANCHORING SYSTEMS | 3.2.2 HILTI HIT-HY 200 A / R V3 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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