PART 3 TENSION LOAD
Side-Face Blowout Failure
Calculations N sb
Calculations ACI 318-14 Chapter 17 Provision Comments for PROFIS Engineering anchor group in tension
N sb
17.4.4.1 For a single headed anchor with deep embedment close to an edge ( h ef
> 2.5c a1 ), the nominal side-face blowout strength , N sb , shall not exceed
N sb
= 160c a1
A brg λ a f ́c ( 17.4.4.1 ) 17.4.4.2 For multiple headed anchors with deep embedment close to an edge ( h ef
> 2.5c a1
) and anchor spacing less than 6ca1 , the nominal strength of those anchors susceptible to a side-face blowout failure N sbg shall not exceed
N sbg
= 1 + s
6c a1
N sb
( 17.4.4.2 )
where s is the distance between the outer anchors along the edge , and N sb is obtained from Eq .
( 17.4.4.1 ) without modification for a perpendicular edge distance . PROFIS Engineering permits h ef
-values ranging between 4d anchor and 25 ” to be input for the cast-in anchors in its portfolio .
PROFIS Engineering calculates side-face blowout when the anchor effective embedment depth ( h ef
) is greater than 2.5 times the nearest fixed edge ( c a1
). The applied tension load creates lateral bursting stresses at the head of the anchor which cause the concrete to “ blow out ” at the face of the fixed edge . Side-face blowout is a possible failure mode for cast-in anchors and post-installed undercut anchors ; however , PROFIS Engineering does not consider side-face blowout for the HDA-P and HDA-T undercut anchors in its portfolio because it will not be a controlling tension failure mode for these anchors .
When modeling a group of anchors in tension , the side-face blowout strength for a single anchor ( N sb
) is calculated , and modified by the factor ( 1 + s / 6c a1 ). PROFIS
Engineering designates this factor “ α group
”. The parameter “ s ” corresponds to the distance between the outer anchors ( e . g . s y1
+ s y2 in the illustration to the left ) along the fixed edge being considered for side-face blowout .
The PROFIS Engineering cast-in anchor 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 ) λ a is a modification factor for lightweight concrete .
f ́c corresponds to the concrete compressive strength .
Reference the Variables section of the report for more information on the parameters c a1
, c a2 , A brg
, λ a
, f ́c and s .
Reference the Equations section of the report for more information on the parameter N sb
.
Reference the Equations and Calculations section of the report for more information on the parameter α group
. Reference the PROFIS Engineering report section for N sb
( single anchor ) for information on the parameter α corner .
119 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions