by Kelly A. Mello

Created on: April 12, 2007   Last Updated: April 30, 2007

McDonald's doesn't have the only famous arch in the world. Many other structural beauties also adorn themselves with these curved doorways and windows, such as The Arc de Triomphe in Paris, France. In order to understand the great significance of the arch in structural terms, we must first learn what an arch is.

WHAT IS AN ARCH?

An arch is, as I said earlier, a window or door with a curved top. These structures can support an immense amount of weight, which is probably why they were created by the Indus Valley civilization around 2500 BC. The key component to an arch is the topmost brick, appropriately called the keystone. All of the surrounding bricks, or voussoirs, rely on the keystone for balance.

IT'S HISTORY

The Romans soon improved upon the arch and used it in many of their buildings. The Coliseum, for example, is comprised of 80 arches used as entrances and exits. From there, different types of arches were made including:

Triangular
Semi-circular
Segmental
Unequal round
Lancet
Equilateral pointed
Shouldered Flat
Three-foiled Cusped
Horseshoe
Three-centered
Elliptical
Inflexed
Ogee
R everse Ogee
Tudor
Flat
Gothic
Moorish

THE IMPORTANCE OF ARCHES

Back in the day, the functions of the arch were numerous. As in the coliseum, they provided a quick entrance and exit for large numbers of people to get where they needed to go very rapidly.

In Rome, the arches were built in large trains with a gutter-type top. This served as the aqueducts which moved water to various places. They could have made the aqueducts out of a wall of stone, but then it would act as a barrier. The arches allow people to pass underneath them in their daily routines. Furthermore, the arches helped them save on building materials which they could use for other projects. Arched aqueducts use about 40% of what a wall of stone would consist of.

Today the arch is a major component in many bridges, as well as other structural pieces because it eliminates tensile stresses in spanning an open space. While many common building materials such as stone, cast iron and concrete can resist compression, they are weak tension is applied to them. Arches remove this factor by being self-supporting. This enables it to hold a great deal of weight, including multiple levels, which is important to most, if not all, structures of today.

The arch's importance is not just based upon its usefulness. They are also beautiful structures which this world would be rather bland without. Now when you pass by the golden arch at Mickie D's, you will know just where the idea came from.

Learn more about this author, Kelly A. Mello.
Click here to send this author comments or questions.