Calculator Inputs
Example Data Table
| Case | b | t | L | Load | Pax | e | f′m | Output highlights |
|---|---|---|---|---|---|---|---|---|
| Wall strip | 1000 mm | 200 mm | 3.0 m | 6.0 kN/m + self-weight | 0 kN | 0 mm | 10 MPa | Mtotal, stresses, utilization, status |
| Axial + eccentric | 1000 mm | 200 mm | 3.0 m | 10 kN point | 50 kN | 20 mm | 12 MPa | Combined stress check plus capacity margins |
Formula Used
- A = b·t and S = b·t² / 6 for a rectangular section.
- Uniform load (simply supported): M = w·L² / 8, V = w·L / 2.
- Midspan point load: M = P·L / 4, V = P / 2.
- Eccentric axial moment: Mecc = Pax·e.
- Combined extreme stress: σ = Pax/A ± M/S.
- Nominal flexural capacity: Mn = fr·S.
- Design capacity: Mdesign = (φ·Mn)/SF.
How to Use This Calculator
- Enter the effective width, thickness, and span or clear height.
- Select the load model and provide uniform load or point load.
- Choose whether to include self-weight, then set unit weight.
- Add axial load and eccentricity if compression is present.
- Provide masonry strength and either auto or manual rupture stress.
- Set allowable tension, φ, and a safety factor for your workflow.
- Press Calculate to view demand, stresses, and capacity together.
- Use Download CSV or Download PDF to keep project records.
Technical Article
1) Purpose of flexural checks
Masonry panels can behave like slender strips spanning between supports. Wind pressure, equipment impacts, eccentric axial loads, and uneven bearing can introduce bending. A flexural check estimates demand moments, resulting stresses, and whether the section can safely resist tension without cracking beyond acceptable limits.
2) Selecting the design strip
For walls, an effective strip width is commonly taken as 1.0 m (or 1000 mm) to simplify load conversion. Thickness equals the wall thickness for out-of-plane bending. For in-plane bending, the depth axis changes and the section modulus increases, which can significantly improve capacity for the same material strength.
3) Loads and boundary assumptions
This calculator uses simply supported formulas for a uniform line load and a midspan point load. These are standard preliminary models and provide clear, conservative demand estimates in many situations. If your wall is fixed, partially fixed, or has openings, the true moment distribution may differ.
4) Combined axial and bending stress
Many masonry walls carry compression from floors or roof systems. When that compression is eccentric, it creates an additional moment, increasing bending stress. The combined stress at the extreme fibers is computed with the axial term plus or minus the bending term, allowing both maximum compression and maximum tension to be reviewed.
5) Strength parameters and resistance
Material inputs include masonry strength f′m and a rupture stress fr. If you choose auto mode, the tool applies a conservative heuristic based on f′m. For project work, you should confirm fr, allowable tension, and strength reduction factors using the governing masonry design standard and specifications.
6) Utilization and decision making
Two utilization measures are evaluated: moment utilization compares total moment demand to reduced design capacity, while tension utilization compares maximum tensile stress to allowable tensile stress. The reported utilization is the larger of the two, providing a single indicator for quick screening and iteration during design.
7) Example dataset and interpretation
Example inputs for a wall strip: b = 1000 mm, t = 200 mm, L = 3.0 m, uniform load w = 6.0 kN/m, unit weight = 20 kN/m³ (included), f′m = 10 MPa, φ = 0.90, safety factor = 1.50, and no axial load. The calculator reports Mtotal in kN·m, extreme stresses in MPa, and a utilization ratio for pass/check decisions.
8) Good practice notes
Always verify the support condition, load path, and whether cracking limits apply to the element’s function (façade, partition, or structural wall). Where needed, include reinforcement, increase thickness, reduce span, or adjust detailing to improve stiffness and control serviceability.
FAQs
1) What does the utilization ratio mean?
Utilization is demand divided by capacity (or allowable stress). A value below 1.0 indicates the check passes under the selected assumptions and factors. A value above 1.0 suggests revising geometry, loads, or material parameters.
2) When should I use out-of-plane versus in-plane bending?
Use out-of-plane for wind or lateral pressure bending the wall thickness. Use in-plane when the wall acts as a deep beam or pier bending about its width. Choose the axis that matches the actual load direction and supports.
3) Does the tool consider reinforcement?
This version models unreinforced behavior using section modulus and rupture-based capacity. If reinforcement is present, capacity and stress distribution can change materially. For reinforced masonry, use a dedicated reinforced flexure design check aligned with your standard.
4) Why include self-weight?
Self-weight contributes additional line load, increasing bending moment and shear. Including it is helpful for tall panels or thick units where dead load is not negligible. If dead load is already included elsewhere, you can disable it here.
5) What is eccentricity doing in the calculation?
Eccentricity multiplies axial load to create an added moment, M = Pax·e. Even small offsets can meaningfully increase tension on one face. Set e to zero if the axial load is applied concentrically.
6) Is the “auto” rupture stress always acceptable?
No. Auto mode is intended for preliminary estimates and may be conservative or mismatched to your materials. For final checks, input project-specific values and confirm them with test data, specifications, and the governing design standard.
7) How should I document results for submittals?
Enter notes describing the wall location, loading source, and assumptions, then export the CSV or PDF. Attach the exported file with sketches and load calculations so reviewers can trace each input and verify the model.
Accurate flexural checks help keep masonry elements safe always.