HAC_Technical-Guide
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Cast-In Anchor Channel Product Guide, Edition 1 • 02/2019
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
11.1 Code Compliance 11.2 HAC Price Index 11.3 Design Optimization 11.4 HAC Layout 11.5 Substrate Considerations 11.6 HAC Specications
11.3 HAC DESIGN OPTIMIZATION
Introduction
For projects where thousands of conditions are covered by one anchor channel type, using a $15 vs $18 dollar solution could
ultimately bring significant cost savings. This section provides work arounds to help designers optimizing the anchor channel
selection without having to select a more expensive anchor channel. The guidelines or work-arounds discussed in the next section
require minimum impact to the design and it is generally acceptable. Always evaluate the overall cost of each solution considering
the entire requirements of the entire system.
The following recommendations are intended to be used when the anchor channel is over utilized up to 10%-15%, with minimum or
no impact to the fixture and without change the substrate conditions (i.e. using stirrups, supplementary reinforcement, increasing
edge distance, etc.) The logical option is always using a bigger channel (except when HAC-70 is the channel under consideration)
and therefore, this option is never discussed in the next guidelines
General guidelines
• Increasing t-bolt spacing helps to distribute the load amongst
the anchors more efficiently. When the channel is slightly
overutilized, consider increasing bolt spacing to reduce
the acting loads at the critical anchor, reducing the overall
utilization in the most utilized anchors.
• Depending on the design parameters and application type,
utilizations exceeding the 100% utilization by 3% may be
acceptable.
• If concrete interaction yields utilizations within 110% for static
loads, try using ACI 318 interaction equations for concrete.
This is only valid for concrete and for failure modes cover by
ACI 318 or AC232.
• When channel lip or anchor-channel connection exceeds the
utilization, consider adding a bolt with smaller channel rather
than increasing channel size
• Price difference between M12 and M16 bolts is minimum. Try
to avoid combining different t-bolt sizes ease installation.
• Closer edge distances do not always mean higher utilizations,
if the back-span or prying leg is increased. The concrete
strength may be reduced but the acting loads at the t-bolts
may be reduced by a larger value.
• Consider the HAC Price index, specially at the typical
conditions.
• Brackets may be wide enough to allow increasing the t-bolt
spacing and use a more feasible channel.
• Brackets may provide enough room to reposition the slotted
hole in order to increase the edge distance or reduce the wind
load eccentricities, without the need of creating a new die.
• Check structural drawings to verify if supplementary
reinforcement (i.e. straight edge reinforcement or Condition A)
can be assumed.
11.3.1 WORK-AROUND IN TENSION
Concrete: Concrete breakout, ΦN
cb
Pullout, ΦN
pn
Blowout, ΦN
sb
Steel: Anchor ΦN
sa
Connection anchor-channel, ΦN
sc
WORK-AROUND: SPREAD THE LOADS AMONGST THE ANCHORS IN A MORE EFFICIENT WAY.
Increasing the bolt spacing is possible when the bracket allows
(i.e. J-hook type bracket). Also, consider the cost difference
between using a bigger channel size versus increasing the width
of the bracket.
By increasing the t-bolt spacing, the loads are redistributed
amongst the anchors in a more efficient way. Thus, reducing the
acting loads at the critical anchor. Figure 11.3.1.1 illustrates this
concept. Left side of Figure 11.3.1.1 has a relatively small t-bolt
spacing. Therefore, t-bolt 1 and t-bolt 2 transfer most of the
loads to the center anchor. Right side of figure 11.3.1.1 has the
same anchor configuration but with increased t-bolt spacing. As
a result, the loads at the center anchor are significantly reduced.
Figure 11.3.1.1 optimization of load distribution from t-bolts to anchors
Blowout Pullout Concrete breakout
Anchor Channel
Lip
Anchor and
channel
connection
Bending of channel