Check four beam load sources with clean inputs. Review reactions, moment, shear, and deflection quickly. Use early estimates before licensed structural design decisions today.
Support reactions: RB = [wL(L/2) + Σ(Pa)] / L. RA = wL + ΣP - RB.
Shear at x: V(x) = RA - wx - ΣP for loads placed left of x.
Moment at x: M(x) = RAx - wx2/2 - ΣP(x - a).
Section properties: I = bd3/12. S = bd2/6.
Bending stress: fb = M / S. Deflection: curvature is integrated from M / EI.
Use this tool for preliminary planning only. Confirm final beam sizing with local code requirements and a licensed professional.
| Example | Span | Section | Uniform Load | Four Load Sources | Use Case |
|---|---|---|---|---|---|
| Deck girder | 4.8 m | 140 × 280 mm | 2.4 kN/m | 2, 3, 3, 2 kN | Post and joist reaction check |
| Garage header | 5.5 m | 190 × 360 mm | 3.2 kN/m | 4, 5, 5, 4 kN | Opening support planning |
| Temporary platform | 6.0 m | 150 × 300 mm | 2.0 kN/m | 4, 3.5, 2.5, 2 kN | Construction staging review |
A source four beam check studies four separate load sources. These sources may be equipment, posts, roof loads, storage loads, or moving work loads. The calculator keeps each source visible. That helps early planning stay organized. It is not a replacement for signed structural design. It is a clear screening tool for construction decisions.
The support reactions show how much load each bearing point receives. High reactions may need wider seats, stronger posts, or larger footings. Shear shows the vertical force inside the beam. Moment shows the bending demand. Deflection shows the expected vertical movement under service loading. Stress compares the section demand with the selected allowable value.
A beam can pass one check and fail another. A deep member may control deflection well. A narrow member may still carry high bending stress. A short member can have high shear near supports. The best review looks at all values together. Compare factored demand, service movement, and bearing reactions before ordering material.
This tool helps with deck beams, headers, garage openings, shed frames, platforms, mezzanines, and light roof framing. It is also useful when four concentrated loads land on one member. The load positions matter. A load near midspan usually increases moment. A load near a support usually increases reaction and shear.
Use measured spans, not rough guesses. Enter loads in consistent units. Include dead load from the beam, decking, finishes, and fixed equipment. Add live load from people, storage, snow, or construction activity. Conservative assumptions are safer during early estimating. Keep notes for every value. Record the chosen deflection limit. Save the result for later checking. Review changes after any drawing update. Small moves can change the peak moment.
The calculator assumes a straight, prismatic, simply supported beam. It does not check buckling, connection strength, notches, holes, fire rating, vibration, code combinations, or material grading. It also cannot verify field conditions. Permits and occupied structures need professional review. Critical supports need the same care. Use this result to start better questions. Then confirm sizes, fasteners, bearings, and bracing before buying materials. Good planning lowers waste and delays. Check current span tables. Final sizing should follow local codes and project drawings.
It checks a simply supported beam with four separate point load sources. It also includes a uniform load, reactions, shear, bending moment, bending stress, and estimated deflection.
No. It is for preliminary construction planning. Final designs need code checks, material grading, connections, bracing, and professional judgment.
Span and load positions use meters. Point loads use kilonewtons. Uniform loads use kilonewtons per meter. Section dimensions use millimeters.
Service loads are used for deflection checks. Factored loads increase demand for strength screening. This helps separate comfort checks from safety checks.
A ratio such as L/360 limits movement to span divided by 360. A larger denominator gives a stricter movement limit.
Each point load position is measured from the left support. A load at midspan usually raises bending moment more than a load near a support.
Only if you add it in the uniform dead load field. Include beam self weight, decking, finishes, and fixed construction loads there.
It means bending stress and deflection are within the entered limits. It does not confirm shear, bearing, connections, bracing, or local code compliance.
Yes, for early comparison. Enter the matching modulus, allowable stress, and section dimensions. Material specific code checks are still required.
Shear is often highest where reactions enter the beam. Concentrated loads close to supports can increase that local demand.
Contact one for permits, occupied buildings, long spans, heavy loads, unusual supports, or visible damage. Ask a licensed engineer for critical or permitted work.
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.