Corbel Arch: A Primitive Form of Architectural Marvel
What is the term for a primitive form of arch consisting of two stones laid diagonally to support each other over an opening?
a) Circular arch b) Keystone arch c) Triangular arch d) Segmental arch
Explanation:
The term for a primitive form of arch consisting of two stones laid diagonally to support each other over an opening is referred to as a Corbel Arch or Triangular Arch. This type of arch is constructed by offsetting (cantilevering) successive courses of stone or brick at the springline of the walls until they meet at the apex of the archway. This type of construction was notably used by the Mycenaeans in conjunction with a relieving triangle, a triangular block of stone that fit into the recess of the corbeled arch and helped redistribute the weight from the lintel to the supporting walls.
In contrast, a keystone arch is composed of identical wedge-shaped stones, called voussoirs. The keystone is the voussoir at the top of the arch, which holds everything in place without even using glue or mortar. As long as the arch is supported on the sides, it is very strong, stable, and can bear a lot of weight.
The Corbel Arch or Triangular Arch is an architectural marvel that showcases the ingenuity and skills of ancient civilizations. By utilizing the principles of cantilevering and strategic placement of stones, these arches were able to support significant loads and span wide openings without the need for modern construction materials.
The Mycenaeans, in particular, were known for their mastery of the corbel arch technique. They incorporated these arches into their structures, complementing them with relieving triangles to enhance structural integrity and distribute weight effectively.
On the other hand, keystone arches represent a different approach to arch construction, relying on the key voussoir to lock the entire structure into place. This technique is also highly effective in supporting weight and maintaining stability, albeit through a different mechanism.
Understanding the nuances of various arch types not only sheds light on architectural history but also highlights the remarkable achievements of ancient builders. The Corbel Arch and Keystone Arch stand as timeless testaments to human innovation and engineering prowess.