> ## 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.

# Analyze a Steel Bolt Group (ASD)

> Analyze steel bolt groups under eccentric in-plane shear and moment to the AISC Steel Construction Manual, 15th and 16th edition (ASD), using the elastic method.

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    <div className="calc-details-chips"><span className="calc-chip calc-chip--region">United States</span><span className="calc-chip calc-chip--primary">15th and 16th edition (ASD)</span></div>
    <div className="calc-details-head"><span className="calc-card-icon">    <img src="https://mintcdn.com/clearcalcs/32krV4BnKnXD1TTf/images/calculator-icons/ec1dad4ebb9ee37a8ea69e4b8fa6d594c6de8d08b12105a003d1b63743348b6d.svg?fit=max&auto=format&n=32krV4BnKnXD1TTf&q=85&s=a1c4d28a1457a26a26a339070daa0f2d" alt="" width="24" height="24" loading="lazy" data-path="images/calculator-icons/ec1dad4ebb9ee37a8ea69e4b8fa6d594c6de8d08b12105a003d1b63743348b6d.svg" /></span><p className="calc-details-name">Steel Bolt Group Analysis (ASD)</p><a className="calc-details-run" href="https://app.calcs.com/new/sheet/steelBoltAnalysisASD">Run the calc</a></div>
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<div className="calc-answer">
  Analyze steel bolt groups under combined in-plane shear and moment per AISC ASD. The elastic method distributes loads to each bolt using the polar moment of inertia, identifying the critical bolt demand across multiple load combinations in a single run.
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## Method & scope

| Property         | Detail                                                                                                                     |
| ---------------- | -------------------------------------------------------------------------------------------------------------------------- |
| Design standards | AISC Steel Construction Manual, 15th and 16th edition (ASD)                                                                |
| Regions          | United States                                                                                                              |
| Who it's for     | US structural engineers running steel bolt group analysis with multiple load combinations (ASD, AISC 360-16).              |
| What it checks   | Bolt group geometry, Moment of inertia, Load distribution, Critical bolt identification, Multiple load cases, Eccentricity |

#### What it calculates

US structural engineers analyzing bolted steel connections under combined load combinations per AISC ASD. Handles arbitrary bolt group geometry with multiple in-plane shear and moment inputs in a single calculation.

Analyze bolt groups under combined load cases directly, removing the hand combinations required in the free version.

#### Calculation method

The Steel Bolt Group Analysis (ASD) calculator applies the elastic method from the AISC Steel Construction Manual to determine the maximum shear demand on any bolt in an arbitrarily arranged bolt group subjected to in-plane shear and moment loads.

##### Bolt group geometry

Bolt positions are defined by their X and Y coordinates. The centroid of the bolt group is calculated assuming all bolts have equal tributary area:

* x\_c = (sum of all x\_i) / n
* y\_c = (sum of all y\_i) / n

Bolt positions are then expressed relative to the centroid.

##### Moment of inertia

The polar moment of inertia I\_z (in^2, treating each bolt as a unit area) is the sum of squared distances from all bolts to the centroid:

I\_z = I\_x + I\_y = sum(y\_i^2) + sum(x\_i^2)

This is used to distribute the torsional component of applied moment to each bolt location.

##### Load distribution

For a bolt group loaded by a vertical shear V and an in-plane moment M (which may arise from an eccentrically applied load), the elastic method distributes forces as follows:

**Direct shear** (vertical, shared equally):

* V\_p = V / n

**Torsional shear due to moment** (varies by position):

* Vertical component: V\_e = M × x\_i / I\_z
* Horizontal component: H\_e = M × y\_i / I\_z

**Total bolt forces** (vector sum):

* V\_t = V\_p + V\_e (total vertical shear)
* H\_t = H\_e (total horizontal shear)
* Resultant: R = sqrt(V\_t^2 + H\_t^2)

##### Critical bolt identification

The calculator evaluates R at every bolt in the group. The maximum resultant R governs the connection design.

**Utilization** = R / R\_allowable ≤ 1.0

where R\_allowable is the allowable shear strength per bolt (to be specified by the engineer based on bolt grade, diameter, and connection type per AISC Tables).

##### Multiple load cases

The ASD version supports multiple applied load combinations in a single run, each case is analyzed against the bolt group geometry, and the governing (maximum) bolt demand is reported. This removes the need to manually process each combination separately.

##### Eccentricity

When the load is applied at an offset from the bolt group centroid, the eccentricity e is the horizontal distance from the load line to the centroid. The moment input M can be entered directly or derived from the product of shear force and eccentricity.

## How to use it

<Steps>
  <Step title="Open the calculator">
    Open it from **Run calc** in the About this calculator panel above.
  </Step>

  <Step title="Enter your inputs">
    Work through the input sections from top to bottom. Click any input label to see its reference explanation, clause, conditions and assumptions. See [Checks, References, Conditions and Assumptions](/docs/running-calculations/checking-results/checks-references-conditions-assumptions).
  </Step>

  <Step title="Review the results and export">
    Check the utilization of each governing check in the summary, then export a PDF report. See [Views and Export](/docs/running-calculations/exporting-reports/views-and-export).
  </Step>
</Steps>

#### Steel Bolt Group Analysis: Overview

<iframe src="https://www.youtube.com/embed/KtrBHKIFeww" title="Steel Bolt Group Analysis: Overview" className="w-full h-96 rounded-xl" allowFullScreen allow="autoplay; fullscreen" />

#### Steel Bolt Group Analysis (ASD): Example

<iframe src="https://www.youtube.com/embed/i9EcS_zOSyE" title="Steel Bolt Group Analysis (ASD): Example" className="w-full h-96 rounded-xl" allowFullScreen allow="autoplay; fullscreen" />

<iframe src="https://fast.wistia.net/embed/iframe/3zyy634v5o?videoFoam=true" title="Steel Bolt Group Analysis (ASD) video walkthrough" className="w-full h-96 rounded-xl" allowFullScreen allow="autoplay; fullscreen" />

## Common questions

<AccordionGroup>
  <Accordion title="What design method and code does this calculator use?">
    The calculator uses the elastic method per the AISC Steel Construction Manual (15th and 16th edition, ASD). It distributes applied shear and moment loads to each bolt using the polar moment of inertia of the bolt group, then identifies the critical bolt as the one carrying the highest resultant force.
  </Accordion>

  <Accordion title="What are the key inputs?">
    Inputs include the bolt group geometry (X and Y coordinates for each bolt), the applied in-plane shear forces, and the moment and eccentricity of the load relative to the bolt group centroid. Multiple load cases can be applied simultaneously in the ASD version.
  </Accordion>

  <Accordion title="What does the calculator output?">
    The key output is the maximum resultant shear force on the most heavily loaded bolt in the group (R, in kips). This value is compared against the bolt allowable shear capacity to determine if the connection is adequate. The polar moment of inertia and individual shear force components are also shown for verification.
  </Accordion>

  <Accordion title="Can it handle bolt groups under combined shear and moment?">
    Yes. The calculator resolves the applied shear and in-plane moment into direct shear and torsional shear components at each bolt location. The horizontal and vertical components are combined vectorially to give the resultant force on the most critical bolt.
  </Accordion>

  <Accordion title="What bolt grades and types are supported?">
    This is an analysis-only calculator, it determines the force demand on the critical bolt but does not perform the bolt capacity check itself. The resultant demand R can be compared against the allowable bolt shear capacity for A325, A490, or other AISC-listed bolt grades as specified by the engineer.
  </Accordion>
</AccordionGroup>

## Next steps

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