Post-Installed Reinforcing in Fire Conditions 2023
POST-INSTALLED REBAR DESIGN FOR DEVELOPMENT LENGTH AMBIENT TEMPERATURE
The following tables show calculated development lengths per ACI 318 Chapter 25 or CSA A23.3 Chapter 12 for applications not considering fire exposure ( ambient temperature ). Refer to the Hilti North American Product Technical Guide : Post- Installed Reinforcing Bar Guide , dated November 2022 ( Rebar Tech Guide ), for more information on rebar development for post-installed rebar .
For rebar development considering fire exposure , the development length may need to be increased based on the temperature in the concrete for the specified rebar cover and fire duration . Refer to Figures 9 and 10 of this section and Section 2 of this document to determine the development length needed for the fire exposure condition .
Table 7 — Calculated tension development and Class B Splice development lengths for ASTM A615 Grade 40 rebar in walls , slabs , columns , and footings per ACI 318 Chapter 25 for Hilti HIT-RE 500 V3 , not considering fire exposure 3 , 4 , 5
Rebar size
# 3 c b
+ K tr
d b
Min . edge dist . in . 1
Min . spacing in . 2 ƒ ́c = 2,500 psi ƒ ́c = 3,000 psi ƒ ́c = 4,000 psi ƒ ́c = 6,000 psi
l d in .
Class B splice in . l d in .
Class B splice in . l d in .
Class B splice in .
2-1 / 4 2 12 12 12 12 12 12 12 12 # 4 2-3 / 4 2-1 / 2 12 12 12 12 12 12 12 12 # 5 3 3-1 / 4 12 16 12 14 12 12 12 12 # 6 3-3 / 4 3-3 / 4 14 19 13 17 12 15 12 12 # 7 2.5 4-1 / 2 4-1 / 2 21 27 19 25 17 22 14 18 # 8 5 5 24 31 22 28 19 25 15 20 # 9 5-1 / 4 5-3 / 4 27 35 25 32 21 28 17 23 # 10 5-3 / 4 6-1 / 2 30 40 28 36 24 31 20 26
# 11 6-1 / 2 7-1 / 4 34 44 31 40 27 35 22 28 .
Table 8 — Calculated tension development and Class B Splice development lengths for ASTM A615 / A706 Grade 60 rebar in walls , slabs , columns , and footings per ACI 318 Chapter 25 for Hilti HIT-RE 500 V3 , not considering fire exposure 3 , 4 , 5
Rebar size
# 3 c b
+ K tr
d b
Min . edge dist . in . 1
Min . spacing in . 2 ƒ ́c = 2,500 psi ƒ ́c = 3,000 psi ƒ ́c = 4,000 psi ƒ ́c = 6,000 psi
l d in .
Class B splice in . l d in .
Class B splice in . l d in .
Class B splice in .
2-1 / 4 2 12 14 12 13 12 12 12 12 # 4 2-3 / 4 2-1 / 2 14 19 13 17 12 15 12 12 # 5 3 3-1 / 4 18 23 16 21 14 18 12 15 # 6 3-3 / 4 3-3 / 4 22 28 20 26 17 22 14 18
2.5 # 7 4-1 / 2 4-1 / 2 32 41 29 37 25 32 20 26
# 8 5 5 36 47 33 43 28 37 23 30 # 9 5-1 / 4 5-3 / 4 41 53 37 48 32 42 26 34 # 10 5-3 / 4 6-1 / 2 46 59 42 54 36 47 30 38
Footnotes applicable to Tables 7 and 8 : 1 Edge distance is determined using the minimum cover specified by ACI 318 Ch . 25 with an additional 6 % of the development length per suggestions for drilling without an aid per Hilti Rebar Tech Guide Section 3.3 . Smaller edge distances may be possible , for which development and splice lengths may need to be recalculated . For further information on required cover see ACI 318 , Sec . 20.5.1.3.1 . 2 Spacing values represent those producing c b
= 5 d b rounded up to the nearest 1 / 4 in . Smaller spacing values may be possible , for which development and splice lengths may need to be recalculated . For further information on required spacing see ACI 318 Sec . 25.2 .
3 ψ t = 1.0 ; ψ e
= 1.0 for non-epoxy coated bars ; ψ s = 0.8 for # 6 bars and smaller bars , 1.0 for # 7 and larger bars ; ψ g
= 1.0 , See ACI 318 , Sec . 25.4.2.4 . 4 Values are for normal weight concrete . For sand-lightweight concrete , multiply development and splice lengths by 1.18 , for all-lightweight concrete multiply development and splice lengths by 1.33 . See ACI 318 Sec . 19.2.4 . 5 Development and splice length values are for static design . Seismic design development and splice lengths can be found in ACI 318 18.8.5 for special moment frames and ACI 318
18.10.2.3 for special structural walls . For further information about reinforcement in seismic design , see ACI 318 Ch . 18 . l d in .
l d in .
Class B splice in .
Class B splice in .
May 2023
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