A buttress arch, often synonymous with the arch component of a flying buttress, is a structural element used in architecture, particularly in large buildings with vaulted ceilings. Its primary function is to counteract the outward forces pushing against walls.
Understanding the Buttress Arch
Based on the provided reference, the flying buttress (also known as arc-boutant or arch buttress) is a specific type of buttress. It is composed of an arch that extends from the upper portion of a wall to a pier of great mass, in order to convey to the ground the lateral forces that push a wall outwards. These outward forces typically arise from the weight and thrust of heavy vaulted stone ceilings.
Think of it as a structural prop or brace shaped like an arch, leaning against the upper part of a wall to push back against the forces trying to make the wall lean or collapse outwards.
Key Components of a Flying Buttress (Arch Buttress)
A flying buttress system, of which the buttress arch is a key part, typically includes:
- The Arch: This is the core element, an arch spanning from the wall being supported to a sturdy pier. It's this arch that is sometimes referred to as the "buttress arch" or "arch buttress".
- The Wall: The vertical structure (often high) experiencing lateral thrust from its roof or ceiling.
- The Pier: A solid, heavy column or block of masonry positioned away from the wall, receiving the thrust transferred by the arch and directing it safely into the ground.
| Component | Role |
|---|---|
| Buttress Arch | Conveys lateral forces from wall to pier |
| Supported Wall | Subject to outward thrust from vaults |
| Pier | Receives and anchors the thrust |
Why Are Buttress Arches Used?
Buildings with tall, heavy stone vaults exert significant outward pressure on the upper parts of their walls. Without adequate support, these walls could buckle or collapse. Buttress arches, as part of the flying buttress system, provide this essential support from the exterior, allowing for thinner walls and larger windows than would otherwise be possible in such structures.
Examples of where buttress arches (flying buttresses) are famously used include Gothic cathedrals, where they enable the soaring heights and expansive stained-glass windows characteristic of the style.
