Post-Installed Reinforcing Bar Guide
2.0 HOW ARE THEY DESIGNED ? |
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Development length of # 9 existing reinforcing per Eqs . ( 25.4.2.4a & b ): |
l d
=
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3 f y ψ s
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d b
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40 λ c b + K tr
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# 9 bars have 1-1 / 2 in . cover , transverse reinforcing is # 5 @ 16 in . on center ( see Figure 13 ) |
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d b
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40A tr
40 x 0.31
K tr
= = = 0.78 s · n 16 x 1
3 60000 0.8 l d
= 0.625 = 14 in .
40 1.0√4000 2.5
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1.128 |
+ 1.5 + 0.78 |
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C b
+ K tr
= d b
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2 |
1.128 |
= 2.55 ..
· use 2.5
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Note : locate ( e ) reinforcing prior to drilling .
37 in .
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14 in . |
( E ) slab reinforcing
( N ) # 8 @ 12 in . o . c . installed in drilled holes with Hilti HIT-RE 500 V3
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l d
=
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3 f y ψ s
|
d b
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40 λ c b
+ K tr
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d b
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( E ) slab |
d = 8 in . |
3 60000 1.0 l d
= 1.128 = 32 in .
40 1.0√4000 2.5
Tension lap length ( Class B ) of # 8 new reinforcing per Table 25.5.2.1 :
1.3l d
=
2 in .
2 in .
1.3 60000 1.0 40 1.0√4000 2.5
12 in . typ .
( E ) slab
1.0 = 37 in . > 32 .. · use 37 in .
16 in . typ .
Figure 13 — Location of new bars ( not to scale ).
( E ) slab reinforcing
( N ) # 8 bars embedded in drilled holes with Hilti HIT-RE 500 V3 adhesive anchor system
4i n . max .
( N ) # 5 bars embedded in drilled holes with Hilti HIT-RE 500 V3 adhesive anchor system
Mechanically roughened surface , 1 / 4 in . amplitude
( E ) wall
Figure 14 — Cantilevered balcony detail ( not to scale ).
( N ) # 5 @ 16 in . o . c . installed in drilled holes with Hilti HIT-RE 500 V3
Step 4 : Specification Provide post-installed dowels at size , spacing and embedment as indicated on construction documents ( see Figure 14 ).
Dowels : ASTM A615 Grade 60
Anchoring system : Hilti HIT-RE 500 V3 epoxy , install as per Manufacturer`s Printed Installation Instructions ( MPII ), permissible concrete temp . range for installation : 55˚F - 90˚F , concrete shall be dry during dowel installation .
Drill holes using a rotary-hammer drill with carbide bit . Locate existing reinforcing prior to drilling – do not damage ( E ) reinforcing without prior authorization of the EOR .
Bottom bars : Development length of # 5 bars with 1.5 in . cover Assume K tr = 0 ( conservative )
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0.625 |
+ 1.5 + 0 |
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C b
+ K tr
= d b
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2 |
0.625 |
= 2.9 ..
· use 2.5
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9 November 2022