Estimate a preliminary steel connection bolt quantity from connection forces, bolt capacity and practical layout limits.
Connection Forces
Bolt Capacity
Connection Layout
Ready to calculate. Press Calculate Bolt Quantity.
Bolt Quantity Result
Preliminary Required Bolt Count
—
Shear Bolts
—
demand based
Tension Bolts
—
demand based
Rows
—
planned
Bolts / Row
—
planned
Bolt Spacing
—
centre-to-centre
Connection Layout Preview
Connected member
Connection plate
The illustration is a simplified connection layout and is not a fabrication or structural drawing.
Bolt Requirement Summary
Load Requirement
Shear demand—
Tension demand—
Factored shear—
Factored tension—
Shear bolt requirement—
Tension bolt requirement—
Layout Requirement
Connection length—
Connection width—
Minimum edge distance—
Maximum spacing—
Selected rows—
Final planned bolts—
Bolt Layout Details
Item
Result
Unit
Planning Check
How the Bolt Count Is Estimated
The calculator first applies the entered safety factor to the shear and tension demands. It then calculates how many bolts would be required if each bolt resisted the entered design capacity independently.
The final bolt count is then compared with the practical minimum and the available connection layout.
Bolt Rows and Spacing
The connection length is used for the bolt-line direction. The calculator keeps the bolt pattern inside the entered minimum edge distance and attempts to keep the centre-to-centre spacing at or below the entered maximum.
Maximum Intervals = Floor(Usable Bolt Length ÷ Maximum Spacing)
The tool selects a practical number of rows and bolts per row to accommodate the preliminary required quantity.
Important Limitations
This is a preliminary bolt-count and layout planning tool.
It does not perform a complete structural connection design.
It does not calculate bolt shear resistance from bolt grade and diameter.
It does not calculate bolt tension resistance from a design standard.
It does not check bolt bearing resistance.
It does not check plate bearing.
It does not check net-section rupture.
It does not check block shear.
It does not check prying action.
It does not check slip resistance for slip-critical connections.
It does not design welds.
It does not account for eccentric connection moments.
It does not replace an engineer's connection design.
Final bolt quantity, bolt diameter, grade, spacing, edge distances, hole type, connection plate thickness and connection resistance must be verified by a qualified structural engineer using the actual loads and applicable design standard.
Frequently Asked Questions
What does the Steel Connection Bolt Count Calculator do?
It estimates a preliminary number of bolts from entered shear and tension demands, bolt capacities, safety factor and connection layout constraints.
Can it calculate bolts for both shear and tension?
Yes. Separate shear and tension requirements are calculated and the tool can also apply a simple combined interaction approach.
Does it automatically determine bolt spacing?
Yes. It uses the available connection length, minimum edge distance and maximum spacing to produce a preliminary layout.
What does the minimum practical bolt setting do?
It prevents the calculator from producing a connection with fewer bolts than the minimum quantity entered for preliminary planning.
Does the calculator select bolt grade?
No. Bolt capacities are entered directly by the user.
Is the calculated bolt count suitable for final fabrication?
No. The result is a preliminary planning estimate. Final connection design requires verification of all relevant failure modes.