PART 3 TENSION LOAD
Side-Face Blowout Failure
Calculations N sb
Calculations ACI 318-14 Chapter 17 Provision Comments for PROFIS Engineering single anchor 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 )
If c a2 for the single headed anchor is less than 3c a1
, the value of N sb shall be multiplied by the factor
( 1 + c a2
/ c a1 )/ 4 , where 1.0 < c a2
/ c a1
< 3.0 . PROFIS Engineering calculation for Nsb :
N sb
= 160 α corner c a1
A brg λ a f ́c
PROFIS Engineering bearing area values ( A brg ) for the cast-in anchors in its portfolio .
MATERIAL SPECIFICATION
AWS D1.1 Type B Headed Stud
" ASTM F1554 Headed Bolt Gr . 36 , Gr . 55 , Gr . 105 "
Diameter ( d 0
) ( in )
Bearing area ( A brg in 2 ) welded headed stud
Bearing area ( A brg in 2 ) square head bolt
Bearing area ( A brg in 2 ) heavy square bolt
Bearing area ( A brg in 2 ) hex head bolt
Bearing area ( A brg in 2 ) heavy hex head bolt
0.500 |
0.589 |
0.625 |
0.920 |
0.750 |
0.785 |
0.875 |
0.884 |
0.500 |
0.464 |
0.569 |
0.291 |
0.467 |
0.625 |
0.693 |
0.822 |
0.454 |
0.671 |
0.750 |
0.824 |
1.210 |
0.654 |
0.911 |
0.875 |
1.121 |
1.465 |
0.891 |
1.188 |
1.000 |
1.465 |
1.855 |
1.163 |
1.501 |
1.125 |
1.854 |
2.291 |
1.472 |
1.851 |
1.250 |
2.228 |
2.773 |
1.817 |
2.237 |
1.375 |
2.769 |
3.300 |
2.199 |
2.659 |
1.500 |
3.295 |
3.873 |
2.617 |
3.118 |
1.750 |
|
|
|
4.144 |
2.000 |
|
|
|
5.316 |
17.2.6 Modification factor λ a for lightweight concrete shall be taken as :
Cast-in and undercut anchor concrete failure ............................ 1.0 λ where λ is determined in accordance with 19.2.4 .
17.2.7 The values of f ́c used for calculation purposes in this chapter shall not exceed 10,000 psi for cast-in anchors ………………
17.7.1 Unless determined in accordance with 17.7.4 , minimum center-to-center spacing of anchors shall be 4d a for cast-in anchors that will not be torqued , and 6d a for torqued cast-in anchors …………………….
17.7.2 Unless determined in accordance with 17.7.4 , minimum edge distances for cast-in anchors that will not be torqued shall be based on specified cover requirements for reinforcement in 20.6.1 . For cast-in anchors that will be torqued , the minimum edge distances shall be 6d a
.
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 single anchor in tension , the side-face blowout strength for a single anchor ( N sb
) is calculated , and modified by the factor ( 1 + c a2
/ c a1 )/ 4 if a corner formed by the fixed edge distances c a1 and c a2 exists . PROFIS Engineering designates this factor “ α corner ”. The parameter c a2 corresponds to the fixed edge perpendicular to c a1
.
PROFIS Engineering only performs side-face blowout calculations 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 )
The software uses the minimum spacing requirements given in Section 17.7.1 and the minimum edge distance requirements given in Section 17.7.2 for cast-in anchors .
λ a is a modification factor for lightweight concrete . PROFIS Engineering uses the provisions of Sections 17.2.6 and 19.2.4 to calculate λ a
.
f ́c corresponds to the concrete compressive strength being modeled . PROFIS Engineering uses the provisions of Section 17.2.7 to calculate f ́c .
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 corner
.
118 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions