Imperial units
Enter Beam and Load Details
Use published values for the specific LVL product and condition.
Formula Used
For a solid rectangular beam section, the maximum shear stress occurs near the neutral axis. The calculator rearranges that relationship to estimate an allowable shear force.
Vallow = (2 ÷ 3) × Fv' × b × deffective × Cconfiguration
τactual = 1.5 × Vactual ÷ (b × deffective)
Here, b is total built-up beam width, and deffective is beam depth minus entered notch depth. The resulting capacity is compared with the calculated support shear. Use only factors permitted by the product manufacturer and governing design requirements.
How to Use This Calculator
- Enter the individual ply width, number of plies, beam depth, notch depth, and clear span.
- Copy the reference shear value from the exact LVL manufacturer documentation.
- Enter only approved adjustment factors for duration, moisture, temperature, and product conditions.
- Add uniform loading and tributary width, point load, manual shear, and optional self weight.
- Calculate the result and review utilization, capacity, and the displayed load components.
- Confirm bending, deflection, bearing, connections, stability, and all final design requirements separately.
Example Data
| Input | Example value | Purpose |
|---|---|---|
| Individual ply width | 1.75 in | Width of one LVL member |
| Number of plies | 2 | Creates a 3.50 in built-up width |
| Beam depth | 11.875 in | Actual beam depth |
| Reference allowable shear | 285 psi | Example only; verify product literature |
| Uniform area load | 50 psf | Combined area loading assumption |
| Tributary width | 8 ft | Converts area load to line load |
Understanding LVL Beam Shear Capacity
Shear capacity describes how much vertical internal force an LVL beam can resist. This force is usually greatest near supports. It differs from bending capacity. A beam can pass bending checks yet fail shear checks. Designers must review both limits. This calculator estimates allowable shear from the selected beam section and published material value.
Why Beam Geometry Matters
Shear resistance depends on beam width and effective depth. Wider built-up members provide more shear area. A notch reduces the effective depth. This can sharply lower capacity near an end support. Enter the actual notch depth carefully. Use the remaining solid depth for this preliminary check. Never assume separate plies share load without adequate fastening.
Using Published LVL Values
LVL products do not all have identical reference shear values. Use the current value from the exact manufacturer, series, grade, and orientation. The reference value should match the design method and units used for the project. Apply only adjustment factors permitted by the product literature and governing code. This page leaves those factors visible for review.
Interpreting the Load Demand
The calculator combines a uniform area load, tributary width, span, centered point load, manual reaction, and optional beam self weight. For a simply supported beam, each support receives half of a full-span uniform load. A centered point load also produces half its load at each support. Actual framing may behave differently. Cantilevers, partial loads, multiple point loads, and continuous spans require separate analysis.
Reading the Result
The utilization ratio compares calculated demand with available capacity. It also shows estimated maximum shear stress for transparent comparison. Record inputs with project calculations and manufacturer reports. A ratio at or below 100 percent indicates the entered shear check passes. It does not confirm the full beam design. Review bending, deflection, bearing, lateral stability, connections, holes, fire exposure, and service conditions. A high ratio deserves design refinement. A ratio above 100 percent requires a larger section, lower load, or engineered redesign.
Responsible Use
This tool provides a preliminary allowable-stress estimate. It does not replace sealed construction documents. Manufacturer limitations control where they are more restrictive. Field cuts, notches, moisture, damage, and unsupported load paths can change performance. Have a qualified structural professional confirm the final design before materials are ordered or installed.
Frequently Asked Questions
1. What does LVL shear capacity mean?
It is the estimated maximum vertical internal force the beam can resist at a critical shear location. This check is commonly important near supports, where beam shear is often greatest.
2. Is shear capacity the same as bending capacity?
No. Bending capacity addresses flexural stress from bending moment. Shear capacity addresses internal sliding stress. A complete beam design needs both checks, along with deflection, bearing, connections, and stability.
3. Which shear value should I enter?
Enter the published reference allowable shear value for the exact LVL product, grade, orientation, and design basis. Do not substitute a value from a different manufacturer or product series.
4. Why does a notch reduce capacity?
A notch removes material where shear may be high. The remaining depth is smaller, so the effective shear area decreases. Some products require additional notch limits or reductions beyond this preliminary method.
5. Can I add the widths of multiple plies?
This calculator totals the ply widths. That assumption is appropriate only when the built-up member has fastening and detailing that adequately transfers load between plies. Confirm the assembly design separately.
6. What load pattern does the calculator model?
It models a simply supported beam with full-span uniform load, a centered point load, manual added support shear, and optional beam self weight. Other patterns need separate reaction calculations.
7. Should I include beam self weight?
Include it when the applied loading does not already contain beam dead load. Avoid adding it twice. The density input is only an estimate, so use project-specific dead-load information when available.
8. What does utilization above 100 percent mean?
It means the entered shear demand exceeds the calculated allowable capacity. Do not treat that result as acceptable. Revise the beam, reduce load, change the support arrangement, or obtain engineered design guidance.
9. Does this check bearing at supports?
No. Bearing perpendicular to grain, bearing length, post capacity, connection capacity, and support conditions require separate checks. Passing shear does not establish that a support detail is adequate.
10. Can this calculator be used for cantilevers?
Not directly. Cantilever reactions and critical shear locations differ from simple-span behavior. Determine the correct shear diagram and enter a verified support shear only after a separate analysis.
11. Is this result ready for construction approval?
No. This page is a preliminary screening tool. Final construction decisions should use current manufacturer literature, complete loading, applicable requirements, and review by a qualified design professional.