1.0 TENSION
1.4 Side Face Blowout Failure Mode
Results ϕ concrete
Results ACI 318-19 Chapter 17 Provision Comments for PROFIS Engineering
ϕ concrete
17.5.3 Strength reduction factor Φ for anchors in concrete shall be in accordance with Tables …… ……….. 17.5.3 ( b )…………………
Table 17.5.3 ( b ) — Anchor strength governed by concrete breakout , bond , and side-face blowout
Supplementary reinforcement
Supplementary reinforcement present
Supplementary reinforcement not present
Type of anchor installation
Cast-in anchors
Postinstalled anchors
Cast-in anchors
Postinstalled anchors
Anchor
Category [ 1 ] from ACI 355.2 or ACI 355.4
Not applicable
Strength reduction factor ϕ
Tension ( concrete breakout , bond , or side-face blowout )
0.75
1 0.75 2 0.65 3 0.55
Not applicable
0.70
1 0.65 2 0.55 3 0.45
Shear ( concrete breakout )
0.75
0.70
ACI 318-19 strength design provisions treat side-face blowout failure in tension as a “ concrete ” failure mode . The nominal side-face blowout strength ( N sb or N sbg
) is multiplied by one or more strength reduction factors ( Φ-factors ) to obtain a design side-face blowout strength ( ΦN sb or ΦN sbg
). The Φ-factors given in ACI 318-19 Table 17.5.3 ( b ) are used to calculate the design strength for pullout failure , concrete breakout failure and side-face blowout failure in tension . These Φ-factors are relevant to static load conditions . An additional strength reduction factor (= 0.75 ) is used to calculate the design strength for these failure modes if the anchorage design is based on seismic load conditions .
PROFIS Engineering designates the Φ-factor corresponding to “ concrete ” failure modes for static load conditions “ Φ concrete
”, and applies this Φ-factor to the nominal pullout strength , concrete breakout strength and side-face blowout strengths in tension to obtain a design strength . If seismic load conditions are being modeled , PROFIS Engineering also applies the 0.75 seismic reduction factor to the design strength .
PROFIS Engineering only calculates side-face blowout strength for the cast-in anchors in its portfolio . This portfolio is as follows :
• AWS D1.1 Type B headed studs : ( 1 / 2 ” — 7 / 8 ” nominal diameter )
• ASTM F1554 hex head bolt , Gr . 36 , Gr . 55 , Gr . 105 : ( 1 / 2 ” — 1-1 / 2 ” nominal diameter )
• ASTM F1554 heavy hex head bolt , Gr . 36 , Gr . 55 , Gr . 105 : ( 1 / 2 ” — 2 ” nominal diameter )
• ASTM F1554 square head bolt , Gr . 36 , Gr . 55 , Gr . 105 : ( 1 / 2 ” — 1-1 / 2 ” nominal diameter )
• ASTM F1554 heavy square head bolt , Gr . 36 , Gr . 55 , Gr . 105 : ( 1 / 2 ” — 1-1 / 2 ” nominal diameter )
When designing cast-in-place anchors per ACI 318-19 , PROFIS Engineering uses the Φ-factors given in Table 17.5.3 ( b ). PROFIS Engineering defaults to the Φ-factor for “ supplementary reinforcement not present ” ( known as “ Condition B ” in previous ACI 318 editions ) when calculating design side-face blowout strength . If “ Condition B ” is selected as a design parameter in PROFIS Engineering , the software uses the Φ-factor for “ supplementary reinforcement not present ” in Table 17.5.3 ( b ) to calculate the design side-face blowout strength in tension . If “ Condition A ” is selected as a design parameter in PROFIS Engineering , the software uses the Φ-factor for “ supplementary reinforcement present ” in Table 17.5.3 ( b ) ( known as “ Condition A ” in previous ACI 318 editions ) to calculate the design side-face blowout strength in tension .
PROFIS Engineering designates the 0.75 reduction factor noted in ACI 318-19 Section 17.10.5.4 for seismic load conditions “ Φ seismic
”.
Reference the Equations section of the PROFIS Engineering report for more information on the following parameters :
ΦN sb or ΦN sbg
: design side-face blowout strength in tension
Reference the Results section of the PROFIS Engineering report for more information on the following parameter :
Φ seismic
: strength reduction factor for seismic tension
130 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-19 Provisions