From beam inputs to results

1. Start with a complete example

Open Beam Studio and choose Reset example at the top of the Beam Model panel. Values update as you type; there is no Calculate button.

1. Choose a support preset, or select Pin, Roller, Fixed or Free independently at A and B in Geometry or beside the model. Fixed–Fixed, Fixed–Pin, Pin–Fixed and cantilevers in either direction are supported. Unstable pairs show an input error.
2. Enter the span L in metres and section width b and depth h in centimetres.
3. Enter dead and live loads, choose whether to include self-weight, and add any point loads.
4. Set stiffness and material strengths, then choose steel grade, main-bar size, stirrup diameter and cover.
5. Use Model to confirm the 3D geometry, support conditions and applied loading. Open Analysis to select a diagram case and inspect the force response.
6. Open Reinforcement to edit bars and stirrup zones. The engineering summary follows this selected drawing. Expand Selected layout checks to see what passed or needs review.
7. Open Review for load-case comparisons, stock sizes, quantities and report exports. Engineering-summary links take you directly to checks that need attention.

What the reset example should show

Move around the workspace

Follow the four top tabs: Model → Analysis → Reinforcement → Review. Each tab shows one task. The left input panel also has four steps: Geometry, Loading, Materials and Reinforcement; open a step or use its Next button. Compact summaries keep the other inputs visible. On desktop, the input and result panels scroll independently. On a phone, tap Edit beam inputs to expand the input steps. The top tabs stay available as you scroll.

Continuous beams / คานต่อเนื่อง

1. In Model → Spans & supports, set จำนวนช่วง N: 1 for single-span, 2–8 for continuous. Tap คาน 1, คาน 2… to edit one span at a time.
2. Enter each length in metres, width and depth in centimetres, and main/stirrup diameters for the selected span. Choose the interior support at the end of each row, and edit exterior restraints in Geometry or beside the 3D view. Pin and roller supports let the beam rotate continuously; they do not make internal hinges. A free station is an unrestrained change-of-load location.
3. Enter base UDLs in Loading. Expand ตั้งค่าแรงแต่ละช่วง and select a case in Span load multiplier and enter × 1 for its full UDL, × 0 for unloaded, or another nonnegative multiplier. D self-weight always stays on every span. Point loads are entered at a global x from A and are unaffected by UDL multipliers.
4. Use Copy L → alternating Lp1 / Lp2 to prepare separate odd/even UDL cases. Enable strength combinations referencing them. These are snapshots and a starting point for adverse loading; they do not check all possible patterns automatically.
5. Open Analysis to read all support reactions and per-span sagging, hogging, shear and deflection. A negative reaction means uplift and requires a support capable of resisting it. Positive moments tension the bottom face; negative moments tension the top.
6. Changing total L in Geometry or the 3D editor scales all span lengths proportionally. Reports and CSV record the complete model and selected case. Bars and three global stirrup zones remain preliminary full-length schematics: design the actual support reinforcement, anchorage, splices and cutoffs separately.

2. Enter geometry, loads and materials

Choose kgf, metric tonne-force (tf), or kN before entering your example. 1 tf = 1,000 kgf = 9.80665 kN. tf is force; steel quantities continue to use kg mass. Changing units later converts the entered dead/live and point loads automatically.

Read the engineering summary

The summary uses the selected drawing layout. Bending utilization is Mu/φMn; zone shear shows the largest Vu/φVn ratio among active stirrup zones. Their governing strength combinations can differ from the selected diagram case. Fit, strain and other selected checks can still require review when a strength ratio is below 100%. Service deflection uses the envelope of enabled service rows and is compared with the selected L/240, L/360 or L/480 reference. This elastic comparison is not a code pass/fail. Open Selected layout & review notes for bar rows, assumptions and the next review items; issues open these notes automatically.

Enter the loads

1. Enter downward Dead load and Live load as line loads. A slab load in kgf/m² or kN/m² must first be converted using its tributary width.
2. Check Include beam self-weight to add the calculated beam weight to D. Read the amount shown beneath the checkbox.
3. Choose + Add load for a point load. Set its dead/live category, magnitude and distance from A. Use Remove to delete a row.
4. Open Combinations / รวมแรง to edit named D/L rows, enable or disable rows, and choose Service or Strength. The Thai gravity presets are service D + L and strength 1.4D, 1.4D + 1.7L. Choose an enabled row in Diagram combination for the displayed analysis. Reset Thai presets restores these rows; imported or manually edited rows keep their chosen factors until reset.

Choose material and reinforcement settings

SD40 sets main-bar fy to 4,000 kgf/cm²; SD50 sets it to 5,000 kgf/cm². This selection does not change stirrup fyr or E. Enter actual material properties separately.

Choose Auto main-bar size or a specific DB diameter, then select the stirrup diameter, clear cover and aggregate size. DB12 means a 12 mm bar diameter; 12 m stock means the length of a supplied bar.

3. Read the model and analysis

Use the 3D beam to confirm dimensions, then use the load/support sketch and diagrams to understand the selected analysis case.

Use the 3D view

Drag the beam to rotate it, or use the Rotate and Tilt sliders. Choose 3D view, Side or Section for a preset view. Edit Length, Width or Depth beneath the model; a dimension label on the model focuses its matching editor.

Read the results

Inspect a position

Under the diagrams, change Inspect a section or drag the position slider. Position x is in metres from A. Read moment, deflection and V left / right. Different shear values at the same position indicate a jump at a point load or support.

Keep the load cases straight

New model, materials and layer controls

The model shows f′c, main fy and stirrup fyr beside the 3D beam, always in kgf/cm². The end selectors beside the model stay synchronized with Geometry. The load diagram, reaction forces, reaction moments, reinforcement drawing and report all use the selected restraints.

Automatic main-bar layers selects Auto or 1–3 layers. In the drawing editor, Bars is the total count for each face and Layers distributes it into 1–3 rows, with at least 2 bars in each row. The layer arrangement updates the section drawing, area centroid and effective depth. Horizontal clear gap is at least max(25 mm, 2db, 4agg/3); vertical gap is at least max(30 mm, 2db, 4agg/3), following the review brief. These are conservative project checks alongside the selected ACI-style equations, not a complete code detailing assessment.

The SR24 preset sets fyr to 2,400 kgf/cm² and offers RB6, RB9 and RB12. Custom retains 6, 8, 9, 10 and 12 mm diameter calculations; verify the supplied material. RB10 in the comments is treated as a custom 10 mm size, rather than certified SR24 stock. TISI SR24 material scope.

Fixed supports can produce top and bottom tension. Each face with bending demand is checked separately; the overview shows the larger demand/capacity ratio. Compression steel is not credited. Innermost-layer strain must satisfy the implemented tension-controlled limit so all tension layers yield before centroid-based capacity is accepted.

The default Thai gravity register uses 1.4D + 1.7L strength under B.E. 2566 Clause 7(1), a separate 1.4D check and D + L service comparison. Open Edit combinations to edit the factors, or apply the optional supplied-photo or ACI gravity preset. Applying a preset replaces the current register. Basis & limitations shows the Thai Clause 7 cases for wind, seismic, earth/water/fluid pressure and temperature effects. These additional actions are references only and require a suitable structural model; they are not assigned artificial zero demands.

4. Edit main bars and stirrup zones

Choose Beam detailing in the top navigation. The drawing, bar editor and zone summaries describe the selected manual or automatic drawing layout.

Main bars

1. Set the Beam mark, such as B1, to label the drawing.
2. Review the elevation and sections 1-1, 2-2 and 3-3. Click top or bottom bars, or edit the matching row under Main bars.
3. Set the number of bars and the DB diameter for both faces. For example, 3 DB12 means three bars, each 12 mm in diameter.
4. Read the tension-row feedback and expand Selected layout checks. A status of Review selected layout requires attention to the listed reasons.

Stirrups

1. Set the Left zone and Right zone lengths in mm. The middle zone is the remaining span; the end zones must not overlap.
2. Select Left, Middle or Right using its tab, its drawing zone or its section. You can also choose Edit zone in a summary card.
3. Choose Auto spacing or a numeric spacing for the selected zone. RB9 @ 150 means 9 mm stirrups at 150 mm spacing.
4. Review each zone’s length, allocated stirrup count, peak shear and calculated spacing limit. Select Auto again to restore automatic spacing for that zone.

Understand manual choices and resets

Editing either bar row keeps both rows as manual choices when beam inputs change. Editing either end-zone length keeps both lengths. Numeric per-zone spacing also stays selected. Recheck the drawing after changing the beam or loads.

Auto select steel rebuilds the drawing from the current sidebar settings and resets its bar rows, zone lengths and spacing. Reset example restores the example beam and clears manual drawing choices. Reset preserves the force-unit selection, beam mark, deflection reference and 3D orientation.

Selected checks satisfied means the implemented checks passed. It does not establish a complete design or construction-ready detailing.

5. Compare, export and resolve issues

Use the Review tab to compare the automatic section recommendation and understand the assumptions behind each output. The engineering summary above the tabs’ content continues to check the selected drawing layout.

Engineering checks

Automatic sizing utilization in the detailed Review panel is demand divided by design strength for the automatic section recommendation. The summary’s bending and shear ratios check the selected drawing layout, including manual changes. The load-case table compares all enabled rows. The default uses Thai gravity load factors with D + L service. The supplied photograph's 19 strength rows and ACI gravity reference remain optional presets. Earthquake inputs require separate project analysis; the default D/L register does not reference them. Under Compare SD40 / SD50 and bar sizes, choose Use to update the sidebar grade and main-bar preference.

Choose L/240, L/360 or L/480 under Deflection reference. This is a user-selected elastic comparison, not a code pass/fail. For continuous beams the governing ratio uses the actual physical support gap or overhang, even when a free station divides it. Quantity estimates refer to the automatic section, exclude the opposite-face hanger row and detailing allowances, and can differ from the zoned drawing’s counts.

Save the output you need

If a result is missing or needs review

Scope of the current app

Beam Studio handles one to eight connected rectangular spans with constant E and I, signed transverse loads and ideal restraints. Axial force, torsion, variable sections, internal hinges and settlement are outside this model. The Thai gravity preset supplies load factors; its reinforcement features still implement selected ACI 318-19 section checks. This combination of selected methods does not establish complete Thai legal or ACI compliance. Verify the applicable design standard and all required load combinations for your project. Anchorage, laps, hooks, support extensions, seismic confinement, cracking, creep, shrinkage and long-term deflection need separate engineering assessment. SVGs and stock estimates are preliminary, not construction or purchasing instructions.