> ## Documentation Index
> Fetch the complete documentation index at: https://calcs.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# Column Bracing Connection: Double Gusset Configurations
> Design internal and external double gusset brace connections, where the brace force is split between two gusset plates.
**Where you can use this:** [Atlas Tube HSS Connections Hub](https://connectionshub.atlastube.com/login/organisations?src=CALCSDOCS) only
**Status:** Beta · **Region:** US · **Design codes:** AISC 360-22
## What this calculator does
The Column Bracing Connection calculator supports several gusset configurations. This article covers the two double gusset options, where the brace force is too high for a single plate and is shared across two.
The defining behaviour in both: **every interface demand is halved per plate before being checked against capacity.** Doing that by hand across the bolts, the angles or shear tab, both gusset plates, the beam interface and the column face is where the errors creep in.
| Configuration | Preset | Detail |
| ---------------------------- | ------------------------ | ----------------------------------------------------------------------------------------------------------- |
| Internal Double Gusset (IDG) | `Internal Double Gusset` | Two parallel gusset plates pass through slots in opposite faces of an HSS column, brace bolted between them |
| External Double Gusset (EDG) | `External Double Gusset` | Two gusset plates, one each side, brace force transferred through bolted connecting angles |
Other configurations in the same calculator, unaffected by these presets: Welded Slotted, Bolted Single Slotted Splice, Bolted Knife Plate, Claw Plate. There is a [video on the Claw Plate brace connection](https://www.youtube.com/watch?v=94CUCyxQdKk) if that is the configuration you need.
## Video walkthrough
## Internal Double Gusset
In this configuration the brace connects to the joint using two gusset plates attached to splice plates.
### Inputting key properties
1. Select the `Internal Double Gusset` preset.
2. Enter the HSS column and beam sections and grades.
3. Enter the brace section, grade and angle.
4. Set the brace framing configuration. The brace can run to the column, to the beam, or to both.
5. Enter gusset plate thickness, geometry and slot arrangement.
6. Enter splice plate and shear tab (single plate) geometry.
7. Enter bolt size, grade and layout.
8. Enter weld sizes.
9. Select ASD or LRFD.
The calculator takes the load applied to the brace and derives the corresponding demand for each connection component.
### Limit states
All checks use per-plate demands.
| Interface | Limit states | Reference |
| ------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------- |
| Brace to gusset | Bolt shear, bolt bearing, block shear rupture, brace tensile yielding, tensile rupture, compressive buckling | AISC 360-22 J3, J4 |
| Gusset plate | Tensile yielding and compressive buckling at the Whitmore section, block shear rupture at the brace and column interfaces, bolt bearing | AISC 360-22 J4 |
| Gusset to column (single plate) | Bolt shear, bolt bearing, shear yielding, shear rupture, block shear rupture of the shear tab | AISC 360-22 J3, J4 |
| Column | Web / HSS face local yielding, local crippling, transverse shear yielding, face plastification, punching shear | AISC 360-22 Section J10 |
| Beam to gusset | Shear yielding, shear rupture, tensile yielding of the gusset at the beam interface | AISC 360-22 J4.1, J4.2 |
| Beam | Web local yielding, web shear yielding, local crippling, compression buckling, transverse shear yielding, face plastification and punching shear for HSS beams | AISC 360-22 Section J10 |
| Welds | Beam to gusset and gusset to column | AISC 360-22 J2.4 |
### Summary of Demands
A dedicated section shows both the total interface demands and the per-plate values side by side, so the load split is visible rather than implied.
## External Double Gusset
### Inputting key properties
1. Select `External Double Gusset` under type of bracing.
2. Enter the beam, column, brace and angle sections, their grades, and the rotation of each profile.
3. Enter gusset plate and single plate dimensions and thickness.
4. Enter bolt number, diameter and layout, and weld sizes.
5. Enter the loads on the brace and the loads into the connection.
The sheet checks whether there is physically enough space to combine the sections you have chosen. If the profiles will not fit together, that is flagged at input rather than surfacing later as a geometry problem on the shop drawing.
### Limit states
Demand is split as half the brace force per plate.
| Element | Limit states | Reference |
| ------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------- | ------------------- |
| Bolts at the angles | Bolt shear | AISC 360-22 J3.7 |
| Bolts at the angles | Bolt bearing and tearout | AISC 360-22 J3.10 |
| Angles | Block shear | AISC 360-22 J4.5 |
| Connecting angles | Tensile yielding and rupture, flexural capacity, compression buckling | AISC 360-22 J4, F11 |
| Each gusset plate | Whitmore-section yielding and buckling, tensile yielding and rupture, gross and net shear, block shear including the gusset-to-brace interface | AISC 360-22 J4 |
## Reading the results
Results are reported per limit state with ASD and LRFD demand-to-capacity ratios, grouped into brace capacity, angle capacity, gusset plate capacity, bolt capacity, single plate capacity, weld capacity and column capacity. The governing value is surfaced in the Summary of Capacities below the diagram.
## Assumptions and exclusions
The External Double Gusset configuration is released as a beta calculator with numerical validation still to follow. Treat results as provisional and check governing cases independently.
* Load is assumed to split equally between the two plates.
## Related
* [Column bracing to shear connection linking](/docs/connections_hub/workflows/column_bracing_linking)
**Where you can use this:** [Atlas Tube HSS Connections Hub](https://connectionshub.atlastube.com/login/organisations?src=CALCSDOCS) only
**Status:** Beta · **Region:** US · **Design codes:** AISC 360-22