PART 3 TENSION LOAD
Side-Face Blowout Failure
Variables λ a
Variables ACI 318-14 Chapter 17 Provision Comments for PROFIS Engineering
λ a
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 )
17.2.6 Modification factor λ a for lightweight concrete shall be taken as : Cast-in and undercut anchor concrete failure ......................... 1.0 λ Expansion and adhesive anchor concrete failure ...................... 0.8 λ Adhesive anchor bond failure per Eq . ( 17.4.5.2 ) ....................... 0.6 λ
where λ is determined in accordance with 19.2.4 . It shall be permitted to use an alternative value of
λ a where tests have been performed and evaluated in accordance with ACI 355.2 or ACI 355.4 . 19.2.4 Lightweight concrete
19.2.4.1 To account for the properties of lightweight concrete , a modification factor λ is used as a multiplier of √f ́c in all applicable provisions of this Code .
19.2.4.2 The value of λ shall be based on the composition of the aggregate in the concrete mixture in accordance with Table 19.2.4.2 or as permitted in 19.2.4.3 .
Table 19.2.4.2 — Modification factor λ Concrete Composition of Aggregates λ
All-lightweight
Lightweight , fine blend
Sand-lightweight
Sand-lighweight , course blend
Normal weight
Fine : ASTM C330 Coarse : ASTM C330
Fine : Combination of ASTM C330 and 33 Coarse : ASTM C330
Fine : ASTM C33 Coarse : ASTM C330
Fine : ASTM C33 Coarse : Combination of ASTM C330 and 33
Fine : ASTM C33 Coarse : ASTM C33
0.75
0.75 to 0.85 { 1 ]
0.85
0.85 to 1 [ 2 ]
1 Linear interopolation of 0.75 to 0.85 is permitted based on the absolute volume of normal weight fine friction aggregate as a fraction of the total absolute volume of fine aggregate .
2 Linear interopolation of 0.85 to 1 is permitted based on the absolute volume of normal weight coarse friction aggregate as a fraction of the total absolute volume of coarse aggregate .
1 λ a is a modification factor for lightweight concrete . Generally speaking , ACI 318 applies a multiplier to the parameter √f ́c to “ account for the properties of lightweight concrete ”, and designates this parameter “ λ ”. The parameter “ λ a
“ is a modification of “ λ ” that specifically “ accounts for the properties of lightweight concrete ” with respect to anchoring-to-concrete calculations , hence the subscript “ a ” in “ λ a
”. Per Section 17.2.6 , the modification factor λ , determined per the provisions of Section 19.2.4 , is multiplied by an additional factor that is specific to the type of anchor being used , to obtain the parameter λ a
. PROFIS Engineering uses the λ-value that has been input , to calculate a λ a
-value for the anchor being modeled . PROFIS Engineering users can input a λ-value based on the properties of the lightweight concrete being used in the application . Any λ-value between 0.75 and 1.0 can be input .
PROFIS Engineering only performs side-face blowout calculations for the cast-in anchors in its portfolio . The parameter λ a is included in Eq . ( 17.4.4.1 ) to calculate the nominal side-face blowout strength for a single anchor ( N sb
). Per Section 17.2.6 , if lightweight concrete conditions are being modeled , PROFIS Engineering will use ( λ a
= 1.0 λ ) to calculate N sb with Eq . ( 17.4.4.1 ).
Reference the Variables section of the report for more information on the parameters c a1
, c a2 , A brg
, f ́c and s .
Reference the Calculations section of the report for more information on the parameters N sb
.
19.2.4.3 If the measured average splitting tensile strength of lightweight concrete , f ct
, is used to calculate λ , laboratory tests shall be conducted in accordance with ASTM C330 to establish the value of fct and the corresponding value of f cm and λ shall be calculated by : λ = f ct ≤ 1.0 ( 19.2.4.3 )
6.7 f cm
The concrete mixture tested in order to calculate λ shall be representative of that to be used in the Work .
113 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions