Arch

 The arch is a curved structure sustaining superiorly closing an opening or a hole, so all its parts are compressed and none of them occur extensions. These pressures are transmitted to the support (columns) which holds the arch ends.
 * Arch **

 The arch is a way of making a roof or a doorway or a window without using any beams at all. That's a lot cheaper and easier to get than the big beams. You use the weight of the blocks to hold the arch together.

 The arch is considered one of the most important invention in architecture due to its strength, simplicity and economy.

** Elements of the Arch: **  1- Keystone  2- Voussoir  3- Extrados  4- Impost  5- Intrados  6- Buttress

** Types of arch: **

 The types of arch are: Flat Arch, Corbelled Arch, Semicircular Arch, Venetian Arch, Ogee Arch, Triangular Arch, Bullseye Arch, Bell Arch, Gothic Arch, Skewed Arch, Segmental Arch, Foil Arches, Arches based on circular arcs, and Geometrical Arches.

** Arch uses: **

 The uses of archs are various, some of them are: in churches, aqueducts, bridges, colleges, some homes and monumental structures (triumphal arches).



**“St. Louis Arch Address”, a good example of a big arch **