United States15th edition
The free steel bolt group analysis calculator on Calcs.com returns the shear demand on the critical bolt in a connection. It runs in the browser with no sign-up. This article explains what bolt group analysis is, how eccentric loads are handled, which bolt patterns work, and what a free Calcs.com account adds.
Method & scope
What bolt group analysis is
Bolt group analysis determines how an applied load, meaning shear force plus moment, is distributed among the bolts in a connection. The bolts do not all carry the same force. The critical bolt, the one with the highest resultant shear, governs the connection design. Sizing a connection on any other bolt understates the demand on the worst case.Eccentric loads and the elastic method
Eccentric loads are supported. You enter the load at an eccentricity from the bolt group centroid, and the free calculator resolves the resulting in-plane moment. That moment is distributed to each bolt using the elastic (instantaneous center) method. The output is the resultant shear on each bolt, so the critical bolt is identified for you.Bolt patterns you can analyze
Any bolt pattern is supported, symmetrical or unsymmetrical. Bolts are defined by X and Y coordinates rather than chosen from a fixed list of layouts. That means L-shaped groups, circular patterns and irregular arrangements all work. You are not limited to a rectangular grid of rows and columns.What the free calculator gives you
The free calculator gives you the demand, that is the maximum bolt shear. It does not return a pass or fail result on its own. To complete the check, compare the maximum bolt shear against your bolt’s design shear strength from AISC Table J3-2. The calculator is completely free and no sign-up is required.What a Calcs.com account adds
A free Calcs.com trial includes the full AISC bolt design check, with the bolt capacity calculated for you rather than looked up by hand. An account also adds saved calculations and PDF export of your results.Before you rely on the result
Calcs.com reports the demand distribution for the bolt group you define. Selecting the connection geometry, the load case and the governing design provisions remains your decision as the engineer of record. Check that the inputs, the bolt coordinates and the assumed eccentricity match the connection you are detailing.How to use it
1
Open the calculator
Open it from Run calc in the About this calculator panel above.
2
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.
3
Review the results and export
Check the utilization of each governing check in the summary, then export a PDF report. See Views and Export.
Next steps
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…
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