Compute timber shear demand, capacity, and utilization instantly. Compare design methods and strength modifiers easily. Download CSV and PDF outputs for tidy documentation records.
| Scenario | Method | V (kN) | b (mm) | d (mm) | k | Fv (MPa) | Cd·Cm·Ct·Cf |
|---|---|---|---|---|---|---|---|
| Light partition beam | ASD | 18 | 63 | 140 | 1.50 | 3.5 | 1.00 |
| Floor joist near support | LRFD | 35 | 89 | 184 | 1.50 | 4.0 | 1.00 |
| Heavier load, improved duration | LRFD | 60 | 140 | 235 | 1.50 | 4.5 | 1.20 |
Timber carries shear mainly through the web zone where fibers slide past each other. Maximum shear occurs near supports and load points, while bending governs midspan. Checking shear prevents sudden diagonal cracking, rolling shear in panels, and connection‑driven splitting. Designers should confirm that the critical section matches the load path and detailing.
The calculator uses applied shear force, section width, and depth to estimate maximum shear stress. A shape factor represents stress distribution, with 1.50 typical for rectangular solid sections. For built‑up members, use the net resisting width and the effective depth at the shear plane. Consistent units are essential because small dimensional changes strongly affect stress.
Base shear strength comes from the selected species and grade, tested under reference conditions. Service factors adjust for load duration, moisture, temperature, and form or size effects. These multipliers can raise or reduce capacity, so they should reflect project exposure and intended life. Where codes require additional modifiers, enter them through the combined factor field.
LRFD compares calculated stress to a resistance‑reduced capacity using a phi factor, producing a utilization ratio. ASD divides adjusted strength by a safety factor, yielding an allowable stress and utilization. Both methods should use the same geometry and applied shear, but the acceptance limits differ. Document the chosen method to avoid mixing factors between design checks.
Use the result block to confirm that utilization stays below one and that capacity exceeds demand. If utilization is high, consider increasing depth, adding plies, reducing load, or improving moisture protection. Also review bearing length, notches, holes, and fastener groups because they can localize shear. Export CSV and PDF outputs to support calculations, reviews, and field communication. Where shear governs, verify that connections transfer load without crushing, and that panel products account for rolling shear. When in doubt, validate assumptions with code tables or manufacturer data. for accuracy.
Enter the design shear at the critical section from your load analysis. For beams, this is often near supports or just beside point loads. Use the same load combination that you used for bending and deflection checks.
Shear stress is not uniform across a rectangular depth. The maximum shear is 1.5 times the average shear V/A. The factor k converts average stress to peak stress so the check is conservative and comparable to code values.
Use the published shear strength for your species, grade, and product type from code tables or manufacturer properties. For engineered products, use the specified shear or rolling‑shear value that matches the failure mode and orientation.
Adjustment factors modify reference strength to reflect service conditions. Wet service, elevated temperature, or long‑term loading typically reduce capacity, while short‑duration loads may increase it. Apply factors required by your governing standard for the member’s environment.
It indicates demand exceeds capacity for the selected method. Reduce shear demand, increase section size, change grade, or improve detailing. Also check for notches, holes, and connections that may further reduce shear resistance at the critical zone.
No. It provides a structured check of shear stress and capacity, but you must confirm factors, limits, and detailing requirements in your local design standard. Always review bearing, stability, and connection design as part of the complete member check.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.