An arch is a structure that spans a space and supports structure and weight above it.
Arches appeared as early as the 2nd millennium BC in Mesopotamian brick architecture and their systematic use started with the Ancient Romans who were the first to apply the technique to a wide range of structures.
An arch is a pure compression form. It can span a large area by resolving forces into compressive stresses and, in turn eliminating tensile stresses. This is sometimes referred to as arch action.As the forces in the arch are carried to the ground, the arch will push outward at the base, called thrust. As the rise, or height of the arch decreases, the outward thrust increases.In order to maintain arch action and prevent the arch from collapsing, the thrust needs to be restrained, either with internal ties, or external bracing, such as abutments.
TYPES OF ARCHES
TERMS
KEYSTONE : A keystone is the wedge-shaped stone piece at the apex of a masonry vault or arch, which is the final piece placed during construction and locks all the stones into position, allowing the arch to bear weight.
SPRINGER : The springer is the lowermost voussoir, located where the curve of the arch springs from the vertical support or abutment of the wall or pier.
VOUSSOIR : A voussoir is a wedge-shaped element, typically a stone, used in building an arch or vault.
IMPOST : In architecture, an impost is a projecting block resting on top of a column or embedded in a wall, serving as the base for the springer or lowest voussoir of an arch.
INTRADOS : The undersurface (as opposed to extrados) of an arch (or vault); also called a soffit.
EXTRADOS : The upper surface of an arch or vault
Arches appeared as early as the 2nd millennium BC in Mesopotamian brick architecture and their systematic use started with the Ancient Romans who were the first to apply the technique to a wide range of structures.
An arch is a pure compression form. It can span a large area by resolving forces into compressive stresses and, in turn eliminating tensile stresses. This is sometimes referred to as arch action.As the forces in the arch are carried to the ground, the arch will push outward at the base, called thrust. As the rise, or height of the arch decreases, the outward thrust increases.In order to maintain arch action and prevent the arch from collapsing, the thrust needs to be restrained, either with internal ties, or external bracing, such as abutments.
TYPES OF ARCHES
TERMS
KEYSTONE : A keystone is the wedge-shaped stone piece at the apex of a masonry vault or arch, which is the final piece placed during construction and locks all the stones into position, allowing the arch to bear weight.
SPRINGER : The springer is the lowermost voussoir, located where the curve of the arch springs from the vertical support or abutment of the wall or pier.
VOUSSOIR : A voussoir is a wedge-shaped element, typically a stone, used in building an arch or vault.
IMPOST : In architecture, an impost is a projecting block resting on top of a column or embedded in a wall, serving as the base for the springer or lowest voussoir of an arch.
INTRADOS : The undersurface (as opposed to extrados) of an arch (or vault); also called a soffit.
EXTRADOS : The upper surface of an arch or vault
PARTS OF AN ARCH
