Many contemporary buildings are characterised by the imaginative use of curves, playing with elements of light and shadow that change throughout the day. Curved walls are often conceived as an aesthetic feature but there are also structural advantages such as wind flow and the ability to resist lateral or compression loads.
Curved walls may be constructed of specially-shaped brick,of cut brick or uncut standard brick. Specially-shaped brick are used when a tight radius is specified or when a smooth appearance is desired. Standard brick are an economical choice for slightly larger radii, when cutting is permissible, or by tapering the mortar joints so the face of the bricks can be laid along the curve. The size of the radius and amount of cutting (if any) is a function of the brick dimensions, its orientation and mortar joint sizes. Bricks placed "head-first" will allow greater radii to be achieved.
Brick arches can be built in several different shapes and styles to give windows and doorways a graceful, finished look. The smooth curves contrast with the textures of surrounding brickwork.
Arches are self-supporting, stabilised by the force of gravity acting on their weight to hold them in compression. This makes them very stable and efficient, capable of larger spans, and supporting greater loads than horizontal beams. The downward load of an arch must be transferred to its foundations. The outward thrust exerted by an arch at its base must be restrained, either by its own weight or the weight of supporting walls, by buttressing or foundations, or by an opposing tie between the two sides. The outward thrust increases as the height, or rise, of the arch decreases.
Domes and vaults evolved from arches