VitraLab Steel Bolt Tension Tool

Tool preview only. This page is not connected to Django, reports, database, or the live calculator.

1. Action

ULS Tension Input

Applied ULS tension on one bolt (kN) Bolt head type

Enter the design tension already distributed to one bolt. Prying, combined shear/tension interaction, and connected-part checks remain separate checks.

2. Bolt grade

Strength and Factors

Bolt grade / property class Code basis Bolt strength, f_ub (N/mm2) γ_M2 k₂ from bolt head type

fub is auto-filled from the selected grade and remains editable for project-specific bolt data. gamma M2 defaults to 1.25.

3. Bolt size

Tensile Stress Area

Bolt diameter / thread size Bolt diameter, d (mm) Tensile stress area, A_s (mm2) Gross area, A_g = πd²/4 (mm2)

Bolt tension resistance uses tensile stress area As. The gross shank area is shown only as a size reference and is not used in this formula.

4. Formula guide

Tension Resistance

Basis: EN 1993-1-4 bolt tension resistance basis used for this Tool: Ft,Rd = k2 fub As / gamma M2.

Standard / non-countersunk selected: k2 = 0.90. For countersunk bolts the tool switches to k2 = 0.63.

5. Result

Tension Summary

Code basisEN 1993-1-4

Bolt grade-

Bolt head type-

f_ub / γ_M2-

k₂-

Bolt diameter / A_g-

Area used, A_s-

F_t,Rd-

Applied ULS tension on one bolt-

Utilization-

Status-

Code applicability-

6. Code notes

Visible Method

Formula used: Ft,Rd = k2 fub As / gamma M2.
For countersunk bolts, k2 = 0.63.
For other bolts, k2 = 0.90.
As is the tensile stress area of the bolt thread and is not the gross shank area.
This Tool shows EN 1993-1-4 as the code basis for both carbon steel and stainless steel bolt grade presets.
The selected bolt grade changes the fub strength value only; the tension expression remains the same.
Prying, bearing, net section, block tearing, bolt shear, and combined shear/tension interaction remain separate checks.

This calculation is provided for preliminary guidance only. VitraLab does not certify or approve the final design. All structural designs must be reviewed and approved by a qualified engineer before manufacture, installation, or use.

7. Report preview

Steel Report

VitraLab

Steel Bolt Tension Strength Tool

Input Summary

Code basis-

Bolt grade-

Bolt head type-

fub / gamma M2-

k2-

Bolt diameter / gross area-

Area used, As-

Result Summary

Applied ULS tension on one bolt-

Ft,Rd-

Utilization-

Preliminary guidance only. VitraLab does not certify or approve final design. Review by a qualified engineer is required before use.