1. Anchor
Channel Systems
2. HAC
Portfolio
3. HAC
Applications
5. Base material
6. Loading
1
i é æ
s ö N ù
1 + å ê ç ç 1 - i ÷ ÷ × i ú
s cr, N ø N 1 ú
i = 2 ê è
ë
û
1.5
ESR-3520 Equation (10)
ö
÷ ÷ h ef ³ 3 h ef
ø in.
1 . 3 h ef
æ
s cr , N = 2 ç ç 2 . 8 -
180
è ö
÷ ÷ h ef ³ 3 h ef
ø mm.
8. Reinforcing
Bar Anchorage
14. Design
Example
Figure 7.3.2.12 a)— at an edge
b)
c) d)
Figure 7.3.2.12 — Idealized projected area of anchor of an anchor channel
loaded in tension near a corner (top) near a corner and in a narrow member
(bottom)
The modification factor for corner effect of anchors loaded in
tension, ψ co,N , shall be computed in accordance with Eq. (15) or
(16) ψ c,N = modification factor for cracked/uncracked concrete
ESR-3520 Equation (12)
then y ed, N = 1.0
ESR-3520 Equation (13)
If c a1 < c cr, N
then y ed, N
æ c ö
= ç ç a1 ÷ ÷
è c cr, N ø
0.5
£ 1.0
ESR-3520 Equation (14)
If anchor channels are located in a narrow concrete member
with multiple edge distances c a1,1 and c a1,2 (as shown in Figure
ESR-3520 Equation (14)
c a2 =distance of the anchor under consideration to the corner
(see figure 7.3.2.13 a, b).
If an anchor is influenced by two corners (as illustrated in Figure
7.3.2.13 c), the factor ψ co,N shall be computed for each of the
values c a2,1 and c a2,2 and the product of the factors, ψ co,N , shall be
inserted in Eq. (6).
æ c
= ç a 2.1
ç c
è cr , N ö
÷
÷
ø 0.5
æ c
= ç a 2.2
ç c
è cr , N ö
÷
÷
ø 0.5
£ 1.0
and
y co , N ,3
£ 1.0
ψ c,N = 1.25
Where analysis indicates cracking at service load levels ψ c,N
shall be taken as 1.0. The cracking in the concrete shall be
controlled by flexural reinforcement distributed in accordance
with ACI 318-14 Section 24.3.2 and 24.3.3, or equivalent crack
control shall be provided by confining reinforcement.
Concrete ψ c,N
Cracked
Uncracked 1
1.25
The anchor qualification tests of ACI 355.2 or ACI 355.4 require
that anchors in cracked concrete zones perform well in a crack
that is 0.012 in. wide. If wider cracks are expected, confining
reinforcement to control the crack width to approximately 0.012
in. should be provided.
Cast-In Anchor Channel Product Guide, Edition 1 • 02/2019
171
c cr , N = 0 . 5 s cr , N ³ 1 . 5 h ef
c cr , N = 0 . 5 s cr , N ³ 1 . 5 h ef
y co , N ,3
where:
£ 1.0
If c a1 ³ c cr, N
then y co, N
0.5
The modification factor for edge effect of anchors loaded in
tension, ψ ed,N , shall be computed in accordance with Eq. (12) or
(13)
æ c ö
= ç ç a2 ÷ ÷
è c cr, N ø
ψ ed,N = modification factor for edge effect
ESR-3520 Equation (16)
If c a2 < c cr, N
ESR-3520 Equation (15)
then y co, N = 1.0
A cracked tension zone is assumed because concrete
possesses relatively low tensile strength, which may be fully
or partly used by internal or restraint tensile stresses not taken
into account in the design. The load-bearing behavior of an
anchor can be significantly influenced by the presence of a
crack passing through the anchor location. For anchor channels
located in a region of a concrete member where analysis
indicates no cracking at service load levels, the following
modification factor shall be permitted
ψ co,N = modification factor for corner influence Figure 7.3.2.13 — Anchor channel with the influence of one edge and one
corner (a and b), two corners and one edge (c), and two edges and one
corner (d).
If c a2 ³ c cr, N
Figure 7.3.2.11 - Idealize failure plane in concrete due to tension forces.
Figure 7.3.2.12 b)— in a narrow member
a)
ψ s,N = m
odification factor influencing the location of
adjacent anchors
170
13. Field Fixes
1
1.5
1.5
1.5
a ù é
a
a
é æ
æ
s ö N ù é æ
s ö N
s ö N ù
1 + å ê ç ç 1 - 2 ÷ ÷ × ua a ,2 ú + ê ç ç 1 - 3 ÷ ÷ × ua a ,3 ú + ê ç ç 1 - 4 ÷ ÷ × ua a ,4 ú
ê è s cr , N ø N ua ,1 ú ê è s cr , N ø N ua ,1 ú ê è s cr , N ø N ua ,1 ú
ë
û ë
û ë
û
Figure 7.3.2.9 — Anchor channel with influence of two edges and
one corner.
Figure 7.3.2.10— Example of anchor channel with non-uniform tension
forces.
12. Instructions
for Use
N 1 = tension force of the anchor which resistance is determined
If an anchor channel is located with the edge c a1 ≥ c cr,N in
all directions the modification factors for concrete edge and
corner effect is taken as 1. For applications where c a1 ≤ c cr,N
for example close to the edge or corner, equation should be
reduced according to the modification factors given below.
The modification factor to account for the influence of location
and loading of adjacent anchors, ψ s,N , shall be computed in
accordance with Eq below.
11. Best
Practices
ESR-3520 Equation (11)
N i = tension force of a neighboring anchor
y s,N3 =
Channels with more than two anchors and loaded in the
span behave like continuous beams on springs, whereby the
stiffness of the springs corresponds to the load-displacement
curve of the anchor. The concrete cone capacity of the anchor
in question is influenced by the distance of and the load on
neighboring anchors. This is taken into account by multiplying
the basic concrete cone capacity N b , with the modification
factor ψ s,N . The factor ψ s,N replaces the ratio A c,N /A° c,N , the factor
ψ ec,N of ACI equation of concrete breakout of headed stud
anchor. For anchor channel with two anchors the factor ψ s,N and
the product (A c,N /A° c,N )ψ ec,N give practically the same results.
10. Design
Software
7.3.2.12), the minimum value of c a1,1 and c a1,2 shall be inserted in
Eq. (13).
istance between the anchor under consideration and
s i = d
≤ s cr,N adjacent anchor, in. (mm)
Figure 7.3.2.8 — Anchor channel with influence of one edge and two
corners.
9. Special Anchor
Channel Design
1 . 3 h ef
æ
s cr , N = 2 ç ç 2 . 8 -
7 . 1
è
7. Anchor Channel
Design Code
y s, N =
4. Design
Introduction