1. Anchor
Channel Systems
2. HAC
Portfolio
3. HAC
Applications
4. Design
Introduction
5. Base material
6. Loading
7. Anchor Channel
Design Code
8. Reinforcing
Bar Anchorage
9. Special Anchor
Channel Design
10. Design
Software
11. Best
Practices
12. Instructions
for Use
13. Field Fixes
14. Design
Example
9.6 — H
AC EDGE DESIGN
9.6.1 — HAC (T) EDGE, HAC (T) EDGE LITE AND HAC S (T) EDGE
DESIGN: INTRODUCTION
HAC EDGE is a system consisting of a rebar edge confinement
plate (EDGE plate) non-structurally attached to a Hilti Anchor
Channel (HAC). The anchor channel itself is covered in the ESR-
3520. Because the EDGE plate is not structurally connected
to the anchor channel, the system is decoupled and the EDGE
plate does not change the behavior of the anchor channel.
Therefore, the design model and technical data can be taken
from ESR-3520 for most of the failure modes.
The scope of the current version of AC232 (June 2017) is limited
to anchor channels with round headed anchors or I-anchors.
Anchor channels with reinforcing bars attached to the anchor
channels are not explicitly covered in the criteria. However,
the testing protocols of AC232 were used to determine the
resistances of HAC in combination with the EDGE plate. The
design provisions of AC232 are valid to design 19 out of the
20 failure modes of an anchor channel required per ESR-
3520. Only the verification for concrete edge failure in shear is
modified, based on rigorous in-house testing to benefit from the
improved load-bearing behavior provided by the confinement
plate with reinforcing bars. The anchorage length is designed in
accordance with ACI 318.
HAC
EDGE Plate
Fixture and self-drilling screws Plate
HAC EDGE or HAC EDGE Lite
Figure 9.6.1.2 — HAC EDGE or HAC EDGE Lite — Components.
The Weakest Link in Top of Slab Applications
The design of cast-in anchor channels requires the verification
of steel and concrete failure modes for tension, shear and
combined tension and shear. An anchor channel is only as
strong as its weakest link. For curtain wall applications, the
weakest link in shear is typically concrete edge breakout failure.
This failure mode is controlled by the geometrical dimensions
and material characteristics of the concrete.
Standard Anchor Channels
The verification of concrete edge breakout of anchor channels
consists of the basic concrete breakout strength of one anchor
of the anchor channel multiplied by a series of modification
factors that account for the anchor spacing, member thickness,
corner effect, state of concrete (cracked or uncracked) and
reinforcement in the concrete member.
The basic concrete breakout strength of one anchor without the
influence of a corner, member thickness or adjacent anchors in
unreinforced concrete is determined as follows:
4
V b = l . a ch , V . f c ' . ( C a 1 ) 3
λ Modification for lightweight concrete
All-lightweight concrete = 0.75
Sand-lightweight concrete = 0.85
α ch,V Factor to account for the influence of channel on concrete
edge breakout strength (10.50, max.)
f’ c Specified concrete compressive strength (psi) (8,500 psi,
max)
c a1 Edge distance of anchor channel in direction 1 (in.) (edge
to center line of anchor)
According to the Figure 9.6.1.3, for standard anchor channels
covered in ESR-3520 the shear loads acting on the fixture are
transferred through the anchor channel into the concrete via the
t-bolts and the anchor elements (1). The failure occurs in front
of the channel profile (2). After reaching the ultimate shear load
the concrete in front of the channel is completely separated
from the rest of the structure. The shear load decreases with
increasing deformation of the channel (3).
HAC EDGE is a new anchoring system that brings value
innovation. It copes with today’s fast track construction
demands and requirements of the curtain wall industry such as
installation tolerance, high wind loads, thin concrete members,
pockets, close edge distances, and lightweight concrete. In
such adverse conditions, HAC EDGE provides more than 2
times the capacity of traditional top of slab anchor channels
where the reinforcing bars are welded to the back of the channel
and outperforms standard anchor channels without reinforcing
bars by up to a factor of 5.
Code Compliance of HAC EDGE
Hilti Anchor Channel with the new rebar edge confinement
plate (HAC EDGE or HAC EDGE Lite) is a solution for Curtain
Wall applications that offers superior concrete edge breakout
performance in shear. HAC EDGE changes the traditional
concept of anchoring to concrete. Instead of relying on the low
capacity of the concrete in tension, it takes advantage of the
tensile strength of the reinforcement attached to the anchor
channel. HAC EDGE optimizes the shear load transfer from
the channel profile into the reinforcing bars and overcomes
the challenges with traditional anchor channels with welded
reinforcing bars.
Anchor channel with rounded head anchors
Figure 9.6.1.1 — HAC EDGE or HAC EDGE Lite — Introduction.
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Figure 9.6.1.3 — HAC — Headed Studs — Behavior of anchor channels loaded in shear (left). Shear load vs displacement curve (right).
Cast-In Anchor Channel Product Guide, Edition 1 • 02/2019
285