Connection Input Form
Use factored loads and project material properties for a fast preliminary check.
Example Data Table
This example shows a typical beam splice check for fast benchmarking.
| Case | Method | Shear Load | Tension Load | Bolts | Bolt Size | Governing Capacity | Combined Utilization |
|---|---|---|---|---|---|---|---|
| Beam splice A | Bearing-type | 180 kN | 45 kN | 4 | M20 | 376.39 kN | 0.49 |
| Brace gusset B | Slip-critical | 120 kN | 30 kN | 4 | M20 | 98.52 kN | 1.23 |
| Column cleat C | Bearing-type | 95 kN | 10 kN | 3 | M16 | 114.60 kN | 0.84 |
Formula Used
These equations provide preliminary estimates for construction planning and early design screening.
- Gross bolt area: A = πd² / 4
- Effective shear area: Av = A × shear area factor
- Effective tension area: At = A × tension area factor
- Bolt shear capacity per bolt: V = 0.60 × Fu,b × Av × shear planes / γ
- Bolt tension capacity per bolt: T = 0.75 × Fu,b × At / γ
- Plate bearing capacity per bolt: Rb = min(1.20 × Lc × t × Fu,p, 2.40 × d × t × Fu,p) / γ
- Slip resistance per bolt: Rs = μ × interfaces × preload factor × Fu,b × A / γ
- Combined utilization: U = √[(Vd/Vcap)² + (Td/Tcap)²]
How to Use This Calculator
- Enter a connection label for reporting clarity.
- Select bearing-type or slip-critical behavior.
- Input factored shear and factored tension loads.
- Fill in bolt size, strength, count, and shear planes.
- Enter plate thickness, plate strength, hole size, edge distance, and pitch.
- Adjust thread, tension area, preload, slip factor, and interface assumptions.
- Press Calculate Connection to display the result above the form.
- Use the export buttons to save the input and result tables.
Important Note
This tool is intended for preliminary estimating and coordination. Always verify project-specific bolt design with the governing structural code, detailing rules, and engineer-of-record requirements.
Frequently Asked Questions
1. What does this bolted connection calculator check?
It estimates bolt shear, bolt tension, plate bearing, slip resistance, reserve capacity, and a combined utilization ratio for preliminary connection review.
2. Is this suitable for final structural design?
No. It is best for screening, estimating, and comparing options. Final design still needs code-based checks, detailing limits, and project engineer approval.
3. When should I choose slip-critical mode?
Use slip-critical mode when slip at service or factored load is unacceptable, such as vibration-sensitive joints, fatigue locations, or alignment-critical assemblies.
4. Why do threads in the shear plane matter?
Threads reduce effective shear area. A smaller resisting area lowers shear capacity, so the calculator applies a reduction when threads pass through the shear plane.
5. What is the tension area factor?
It represents the ratio between effective tensile area and gross shank area. Threaded bolts usually have a net area lower than the shank area.
6. Why can bearing govern before bolt shear?
Thin plates, weak steel, short edge distances, or tight pitch values can reduce bearing resistance enough to control the total shear check.
7. What does combined utilization show?
It blends shear and tension demand ratios into one interaction value. A value above 1.00 signals the selected input set needs revision.
8. What do the CSV and PDF exports include?
They include the submitted inputs and calculated outputs, which helps with estimate packages, coordination notes, design reviews, and recordkeeping.