This page documents the constraints that must be satisfied when specifying bolt positions and loads on anchor channels. Clariti validates these constraints automatically and warns you if inputs fall outside valid ranges.
Channel Overhang Zone
Each anchor channel has an overhang zone at both ends where no bolt or load can be placed. This zone exists because the channel extends beyond the first and last anchors.
Overhang Values
| Channel Family | Overhang x (mm) | Source |
|---|
| CPRO38 | 25 | ETA Table A3 |
| CPRO50 | 25 | ETA Table A3 |
| CPRO52 | 35 | ETA Table A3 |
Visual Representation
Channel layout:
│← x →│ │← x →│
═══════╪═══════════════════════════════╪═══════
│ │
First Last
anchor anchor
│ No │←── Valid bolt zone ────────→│ No │
│loads│ │loads│
Example
CPRO50-350 (350mm length, overhang 25mm):
Channel: 0mm ───────────────────────── 350mm
│ │
Overhang: 0-25mm 325-350mm
│ │
Valid zone: 25mm ──────────── 325mm
Loads placed in the overhang zone cannot be properly distributed to anchors and will produce invalid results. Clariti will reject such inputs.
Minimum Bolt Spacing
When multiple bolts are used, they must maintain minimum spacing from each other. This ensures the force distribution model remains valid.
Minimum Spacing Values
The minimum spacing between adjacent bolts depends on the bolt diameter:
| Channel | Bolt Size | Min Spacing Smin,cbo (mm) |
|---|
| CPRO38 | M10 | 50 |
| CPRO38 | M12 | 60 |
| CPRO38 | M16 | 80 |
| CPRO50 | M12 | 60 |
| CPRO50 | M16 | 80 |
| CPRO50 | M20 | 100 |
| CPRO52 | M12 | 60 |
| CPRO52 | M16 | 80 |
| CPRO52 | M20 | 100 |
Rule
The spacing between any bolt and the end of the bolt group must be at least 5× the bolt diameter.
Example
Using M16 bolts on CPRO50:
- Minimum spacing = 80mm
- If Bolt 1 is at 100mm, Bolt 2 must be at ≥ 180mm
Channel Length Constraints
Each channel family has minimum and maximum standard lengths.
Length Ranges
| Channel Family | Min Length (mm) | Max Length (mm) | Source |
|---|
| CPRO38 | 100 | 3050 | ETA Table A3 |
| CPRO50 | 100 | 3050 | ETA Table A3 |
| CPRO52 | 150 | 3050 | ETA Table A3 |
Standard Variants
Channels come in predefined variants with specific anchor layouts:
CPRO50 Variants:
| Variant | Length | Anchors | Anchor Positions (mm) |
|---|
| CPRO50-100 | 100mm | 2 | 25, 75 |
| CPRO50-150 | 150mm | 2 | 25, 125 |
| CPRO50-200 | 200mm | 2 | 25, 175 |
| CPRO50-350 | 350mm | 3 | 25, 175, 325 |
| CPRO50-1050 | 1050mm | 5 | 25, 275, 525, 775, 1025 |
Anchor Spacing Constraints
Anchor spacing varies by variant and must fall within allowed ranges.
Spacing Limits
| Channel Family | Min Spacing Smin (mm) | Max Spacing Smax (mm) | Source |
|---|
| CPRO38 | 50 | 200 | ETA Table A3 |
| CPRO50 | 50 | 250 | ETA Table A3 |
| CPRO52 | 80 | 250 | ETA Table A3 |
Anchor spacing is fixed for each product variant. You cannot change anchor positions — select a variant that suits your application.
Concrete Member Constraints
Minimum Thickness
The concrete member must meet minimum thickness requirements:
| Channel | hmin (mm) | Source |
|---|
| CPRO38 | 100 | ETA Table B1 |
| CPRO50 | 130 | ETA Table B1 |
| CPRO52 | 185 | ETA Table B1 |
Concrete thinner than hmin may not develop full cone breakout capacity. Additional splitting checks apply.
Edge Distances
Edge distances affect concrete failure capacity:
- Finite edges: Specify actual distance (mm)
- Infinite edges: Use when edge is far enough to have no effect
The critical edge distance depends on embedment depth:
| Channel | hef (mm) | ccr,N (mm) |
|---|
| CPRO38 | 72 | 108 |
| CPRO50 | 99 | 149 |
| CPRO52 | 151 | 227 |
Concrete Condition
The concrete condition significantly affects anchor capacity.
Cracked vs Uncracked Concrete
| Condition | Description | Effect on Capacity |
|---|
| Cracked | Concrete may have cracks at anchor location | Lower capacity (conservative) |
| Uncracked | Concrete verified to remain uncracked | Higher capacity |
Use “Cracked” unless you can demonstrate the concrete will remain uncracked under all load combinations. Most designs should assume cracked concrete.
How It Affects Calculations
The cracking condition changes the k-factor used in concrete cone calculations:
| Channel | kcr,N (cracked) | kucr,N (uncracked) |
|---|
| CPRO38 | 7.8 | 11.1 |
| CPRO50 | 8.1 | 11.6 |
| CPRO52 | 8.7 | 12.4 |
Reinforcement Conditions
Reinforcement in the concrete member affects several failure mode calculations.
Splitting Reinforcement
Controls the reinforcement factor (ψre,N) for concrete cone and splitting calculations.
| Option | Effect |
|---|
| Present | ψre,N = 1.0 — Full concrete capacity |
| Not present | ψre,N = 0.5 + hef/200 — Reduced capacity |
| Channel | hef (mm) | ψre,N (no reinforcement) |
|---|
| CPRO38 | 72 | 0.86 |
| CPRO50 | 99 | 1.0 (capped) |
| CPRO52 | 151 | 1.0 (capped) |
Edge Reinforcement
Controls the edge breakout capacity for shear loads acting toward edges.
| Option | Effect |
|---|
| Present | Higher shear capacity toward edges |
| Not present | Standard edge breakout calculation |
Edge Geometry
When edge reinforcement is present, the geometry affects capacity:
| Option | Description |
|---|
| Straight edge with stirrups | Stirrups provide confinement — highest capacity |
| Straight edge (no stirrups) | Edge reinforcement only — moderate improvement |
If your concrete has standard reinforcement cages with stirrups near edges, select “Straight edge with stirrups” for more accurate (less conservative) results.
Compatible Bolts
Not all bolt sizes work with all channels. Use only compatible combinations:
| Channel | Compatible Bolts |
|---|
| CPRO38 | M10, M12, M16 |
| CPRO50 | M12, M16, M20 |
| CPRO52 | M12, M16, M20 |
Load Constraints
Load Direction
- Tension: Must act away from concrete (pulling on anchor)
- Shear: Can act in any direction parallel to concrete surface
Load Combinations
Clariti accepts:
- Tension only
- Shear only
- Combined tension and shear
Compression loads (pushing into concrete) are handled separately — the anchor channel does not resist compression, only the concrete bearing.
Validation in Clariti
Clariti validates all inputs against these constraints:
| Constraint | Validation |
|---|
| Bolt in overhang zone | Error — cannot proceed |
| Bolt spacing too small | Error — cannot proceed |
| Member too thin | Warning — splitting check applies |
| Edge too close | Warning — reduced capacity |
| Incompatible bolt/channel | Error — cannot proceed |
Summary Table
| Parameter | CPRO38 | CPRO50 | CPRO52 |
|---|
| Overhang x | 25mm | 25mm | 35mm |
| Min channel length | 100mm | 100mm | 150mm |
| Min anchor spacing | 50mm | 50mm | 80mm |
| Max anchor spacing | 200mm | 250mm | 250mm |
| Min member thickness | 100mm | 130mm | 185mm |
| Embedment depth hef | 72mm | 99mm | 151mm |
| Compatible bolts | M10-M16 | M12-M20 | M12-M20 |
