Your first sheet in five minutes

Video: Your first calculation in 5 minutes

This walk-through builds a bending check for a simply supported beam. You will type a few lines, see units work, add a pass or fail message and change a number.

1. Open a new sheet

Open https://civilkit.io/calcs/ . The first tab is a short welcome sheet. To start your own, use File > New sheet, or the New button at the top left. A sheet opens with a few lines of example text. Select all of it and delete it. The editor is on the left and the result is on the right.

A sheet is a plain text file. Its first line is , which the editor adds for you.

2. Type the inputs

Type these lines. Each one is a quantity line: a name, a colon, a value with a unit, and after a bar | a note.

# Beam check

A simply supported beam under a uniform load.

L: 6 m | span
w: 12 kN/m | design load

The result pane shows the heading, the sentence, and two lines like these:

L = 6 m    span
w = 12 kN/m    design load

The result updates as you type. If it does not, press Calculate on the Calculation tab, or Ctrl+Alt+X.

3. Calculate with units

Add a line below the inputs:

L: 6 m | span
w: 12 kN/m | design load
Mstar: w * L^2 / 8 -> kN*m | maximum bending moment

The result shows the formula, the numbers put in, and the answer:

M⋆ = w·L²/8 = 12 kN/m · (6 m)² / 8 = 54 kN·m    maximum bending moment

Three things happened:

Mstar was written as M with a subscript “star”. A name that ends in star after a capital letter becomes a subscript. Greek names work the same way: phi is φ, sigma_c is σ with a subscript c.
^ is a power. L^2 is L squared.
-> kN*m asked for the answer in kilonewton metres. Without it the engine picks a unit itself, which here is also kN·m. Write -> when you want to be sure which unit you get, or a different one (-> N*mm).

4. Add a capacity and a check

Now add the section capacity and a utilisation ratio. This is the complete sheet:

# Beam check

A simply supported beam under a uniform load. The moment **comes out in kN·m** because the
engine tracks the units.

L: 6 m | span
w: 12 kN/m | design load
Mstar: w * L^2 / 8 -> kN*m | maximum bending moment
fy: 300 MPa | yield stress
Ze: 1230000 mm³ | section modulus
Ms: fy * Ze -> kN*m | moment capacity
utilisation: Mstar / (0.9 * Ms)
if utilisation <= 1: "OK" else: "Fails"

The result ends with:

Ms = fy·Ze = 300 MPa · 1230000 mm³ = 369 kN·m    moment capacity
utilisation = M⋆ / (0.9·Ms) = 54 kN·m / (0.9 · 369 kN·m) = 0.163
OK

Look at the Ms line. A stress in megapascals times a volume in cubic millimetres came out as a moment in kilonewton metres. You did not convert anything. The utilisation line divides a moment by a moment, so the units cancel and it is a plain number.

The last line is a one-line condition. It prints the text OK when the ratio is at most 1 and Fails otherwise.

5. Change a number

Change w: 12 kN/m to w: 80 kN/m. The moment becomes 360 kN·m, the ratio 1.08, and the last line reads Fails. Everything after the changed line recalculates as you type.

6. See what the sheet compiles to

A sheet is turned into the Calcpad worksheet language, and the engine runs that. To see the translation, open the Resources tab and choose Show compiled. For the sheet above it is:

'<h1>Beam check</h1>

#markdown
A simply supported beam under a uniform load. The moment **comes out in kN·m** because the
engine tracks the units.
#end markdown

L = 6 m
w = 12 kN/m
M_star = w * L^2 / 8|kN*m
fy = 300 MPa
Ze = 1230000 mm^3
Ms = fy * Ze|kN*m
utilisation = M_star / (0.9 * Ms)
#if utilisation ≤ 1
'OK
#else
'Fails
#end if

(In the compiled view each note is kept as a comment at the end of its line.) You can read it as a short lesson in the Calcpad language: |kN*m is the conversion, #if … #end if is the condition. The language is covered in The Calcpad language. Convert to Calcpad, next to Show compiled, replaces the sheet with that text, for when you want to leave the sheet format for good.

7. Save it

Press Ctrl+S (Cmd+S on a Mac). In browsers that can write files, you choose a place and the sheet is saved as a .sheet file. In other browsers the file downloads. See Saving, opening and working offline.

Where next

All the line kinds: The sheet format.
Why the units came out right: Units.
Draw the moment along the beam: Plots.
Turn the sheet into a form you fill in: Templates with inputs.

Related calculators: Simply supported beam, Cantilever beam. More pages are in Calculators and guides.

Keyboard shortcuts