Answer the following questions. 2. What does arch construction depend on?

1. What is an arch?

2. What does arch construction depend on?

3. What are the main parts of an arch?

4. What is a voussoir?

5. What is a keystone?

6. What is a springing line?

7. What forms can arch curve have?

8. What are the advantages of arches over lintels?

9. Where did Romans use semicircular arches?

10. Who popularized the pointed arch?

11. When was a segmental arch introduced?

VAULT

In building construction, a vault is a structural member consisting of an arrangement of arches, usually forming a ceiling or roof.

The basic barrel form, which appeared first in ancient Egypt and the Middle East, is in effect a continuous series of arches deep enough to cover a three-dimensional space. It exerts the same kind of thrust as the circular arch and must be buttressed along its entire length by heavy walls with limited openings.

Roman architects discovered that two barrel vaults that intersected at right angles formed a groin vault, which, when repeated in series, could span rectangular areas of unlimited length. Because the groin vault's thrusts are concentrated at all four corners, its supporting walls need not be massive and require buttressing only where they support the vault. The groin vault, however, requires great precision in stone cutting, an art that declined in the West with the fall of Rome. Vaulting was continued and improved in the Byzantine Empire and in the Islamic world. Medieval European builders developed a modification, the rib vault, a skeleton of arches or ribs on which the masonry could be laid. The medieval mason used pointed arches; unlike round arches, these could be raised as high over a short span as over along one. To cover rectangular areas, the mason used two intersecting vaults of different widths but of the same height.

Nineteenth-century builders, using new materials, could construct large iron skeletons as frameworks for vaults of lightweight materials. Because the new materials eliminated weight and thrust problems, the simple barrel vault returned to favour for such structures as railroad terminals and exhibition halls. In many modern frame systems the vault has lost its functional significance and become a thin skin laid over a series of arches. The reinforced-concrete shell vault, a bent or molded slab, is an important innovation.

Quadripartite gothic rib vault	Sixpartite gothic rib vault	Net vault
Single vault (barrel vault)	Groin vault	Dome

Дата добавления: 2015-10-26