What are Arches?
An arch is a structure which is constructed to span across an opening. It generally consists of small wedge-shaped units which are joined together with mortar.
Elements of an Arch
- Intrados: It is the inner curve of the arch.
- Extrados: It is the external curve of an arch.
- Soffit: It is the inner surface of the arch.
- Voussoirs: These are the wedge-shaped units forming the courses of an arch.
- Skewback: It is the inclined or splayed surface on the abutment which is so prepared to receive the arch and from which the arch springs.
- Crown: It is the highest point on the extrados.
- Key: It is the wedge-shaped unit at the crown of an arch.
- Springing points: These are the points from which the curve of an arch springs.
- Springing line: It is an imaginary line joining the springing points of either end.
- Abutment: It is the end support of an arch.
- Piers: These are the intermediate supports of an arcade.
- Span: It is the clear horizontal distance between the supports.
- Rise: It is the clear vertical distance between the highest point on the intrados and the springing line.
- Centre: It is the geometrical center of the curve of an arch.
Also Read – What are Spillways? Types of Spillways