A segmental arch follows part of a circle above an opening. The span and rise determine its curvature. BrickCore draws the arch, distributes the bricks and shows how the joints meet.
Enter the clear span, rise, brick dimensions and joint width. Check the radius, springing points and brick layout. Download the setting-out drawing and full-size cutting profiles for A4 or A3.
segmental arch
Measure the clear span between the springing points. Measure the rise vertically from their baseline to the underside of the crown. Also enter the brick size, arch-ring depth and desired joint.
A segmental arch is part of one circle. Its radius is span × span ÷ (8 × rise) + rise ÷ 2. Bricks are divided along the arc; dividing the straight span by the brick width does not give that curved layout.
For a 160 cm span and 40 cm rise, the radius is 160 × 160 ÷ 320 + 20 = 100 cm. The circle centre lies 60 cm below the springing line. Brick size and joints then determine the brick count.
A free account lets you view the calculation and drawing. The PDF contains calculated dimensions and cutting profiles; a download costs one credit. Follow the scale on the worksheet. Print full-size cutting templates at 100% with ‘fit to page’ disabled.