Arch+Presentation

- The arch was perfectioned by Etruscans

- In some occasions, arch was used to represent a victory and an entry at the same time

- Example of arch use: Coliseum

- Parts of an arch: Keystone (the most important, keep the arch together), **rise**, voussoirs, extrados, Springer, skewback, **springing line**, intrados, crown and **haunch**.

Advantages: -The absence of tension in the arch means that it can sustain much greater spans than beams can achieve, and it can use materials that are not strong in tension. -Durable structures.

Disadvantages: - The form makes some balance problems that doesn’t exist in lintel systems. - Expensive to build - Arch bridges are very heavy so they need extensive foundations

There exist many types of arches: //natural// arches (made by nature), //roman// arches, //gothic// arches (narrow type), //triumphal// arches (for victories), //blind// arches (in-filled with solid constructions), //Syrian// or //large// arches (usually for bridges) or **//Moorish//** arches (extend beyond a semi-circle. Ex: Islamic and Indian architecture)