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Calcimator

Brick Arch Calculator

Calculate the radius, voussoir count, skewback angle, and arc length for segmental and semicircular brick arches.

Inputs

in
in
in
in

Results

Arch Radius

24.25 in

≈ 7 credit cards

Voussoir Count

11 bricks

Skewback Angle47.9°
Arc Length40.57 in
Spring Point Offset16.25 in
How to Use This Calculator
  1. Enter the arch span width (the clear opening from spring point to spring point) in inches.
  2. Enter the rise height from the spring line to the crown of the arch.
  3. Input the brick width, used as the voussoir depth along the arch, and the mortar thickness at the intrados.
  4. Select the arch type: segmental or semicircular.
  5. Review the arch radius, voussoir count, skewback angle, arc length, and spring point offset.

How the result changes with Span Width

Span WidthArch RadiusVoussoir Count
3523.14 in11 bricks
92136.25 in25 bricks
160404 in43 bricks
217739.77 in57 bricks

What each input means

Span Width
Clear opening width of the arch from spring point to spring point.
Rise Height
Height from the spring line to the crown of the arch.
Brick Width
Width of the brick (used as the voussoir depth along the arch).
Mortar Thickness at Intrados
Mortar joint thickness at the inner (intrados) face of the arch.
Arch Type
1 = Segmental arch, 2 = Semicircular arch.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Span Width = 36, Rise Height = 8, Brick Width = 3.625, Mortar Thickness at Intrados = 0.25 = 5 input(s) provided
  2. Calculate Arch Radius
    Arch Radius
    24.25 = 24.25
  3. Calculate Voussoir Count
    11 = 11
  4. Calculate Skewback Angle
    Skewback Angle
    47.9 = 47.9
  5. Calculate Arc Length
    Arc Length
    40.57 = 40.57

Engine last updated . Checked against 3 independently-derived tests — how we verify calculators.

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