PART 3 TENSION LOAD
Side-Face Blowout Failure
Results ϕ concrete
Results ACI 318-14 Chapter 17 Provision Comments for PROFIS Engineering
ϕ concrete
17.3.3 Strength reduction factor ϕ for anchors in concrete shall be as follows when the load combinations of 5.3 are used :
( c ) Anchor governed by concrete breakout , side-face blowout , pullout , or pryout strength
( ii ) Tension loads Cast-in headed studs , headed bolts , or hooked bolts
Condition A
Condition B
0.75 0.70
Post-installed anchors with category as determined from ACI 355.2 or ACI 355.4
Category 1 |
0.75 |
0.65 |
( Low sensitivity to Installation and high reliability ) |
|
|
Category 2 |
0.65 |
0.55 |
( Medium sensitivity to Installation and medium reliability ) |
|
|
Category 3 |
0.55 |
0.45 |
( High sensitivity to Installation and lower reliability ) |
|
|
Condition A applies where supplementary reinforcement is present except for pullout and pryout strengths .
Condition B applies where supplementary reinforcement is not present and for pullout and pryout strengths .
ACI 318-14 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 318-14 Section 17.3.3 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 , PROFIS Engineering uses the ϕ-factors given in ACI 318-14 Section 17.3.3 ( c )( ii ) to calculate the design side-face blowout strength .
PROFIS Engineering defaults to the Condition B ϕ-factor when calculating design side-face blowout strength . If Condition A is selected as a design parameter , PROFIS Engineering uses the Condition A ϕ-factors given in ACI 318-14 Section 17.3.3 to calculate the design side-face blowout strength in tension .
PROFIS Engineering designates the 0.75 reduction factor noted in ACI 318-14 Section 17.2.3.4.4 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
124 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions