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In architecture, a vault is an arched structure of masonry, forming a ceiling or canopy. Vaulting makes it possible to roof over a comparatively large space using bricks, stone blocks or concrete. Until the development of metal girders and trusses in the 19th century, the only alternative was to use long wooden rafters or long stone lintels — much simpler than vaulting; but cruder and more expensive as well, and ultimately limited by the length of wood or stone available. The Romans made an art form of the vault and it has remained popular ever since.
Types of vaulting through European history
Construction Medieval vaulting was created over a period of 600 years between 900 and 1500AD (roughly). There were also different types of vault in different places. There must have been very many experiments in their construction. They all had one thing in common though. They were built of stone at a height without the benefit of precise predictable measurement. They would, probably, all be built under a roof to protect the work and the workers and all would require a scaffold to support the stones the mortar and the workmen. The scaffold would also need to support machines, usually treadmills, to lift large stones on occasions. Large bosses for example at the apex of vault ribs. Medieval mortar took a long time to achieve its final set and medieval vaulting is noted for the large size of the mortar joints. This means that it must have been supported for some time before the support was removed. The large mortar joints were an economical solution to the problem of lack of precision in that stone would not have to be precisely cut and the mortar joint could be more or less wide depending on circumstances. It may be interesting to note that there are medieval paintings showing the construction of cathedrals and churches. They show details and quite mundane tasks but they do not show the construction of vaults, which suggests that they were out of sight, under a roof and above scaffolding. The obvious way to construct a vault is by constructing scaffolding to hold up all the pieces. This is extremely expensive, however. Most classic vaults are self-supporting in construction, or built with jointures. In a self-supporting vault, the starting arches have to be built with scaffolding, but after that, the bricks or stone blocks interlock, permitting additions until the vault is complete. One of the easy ways to start an arch or construct a vault uses a "jointure", a beam or clamp with faces to grip the top blocks. Each time a block is added, the jointure is walked up to the next block on that side. The construction of jointures used to be a trade secret of masons. Some classic vaults are made to be constructed with jointures. There are several inexpensive ways to construct concrete vaults. One of the simplest (invented by Paolo Soleri) is to form or dig a mold in the earth, pour the concrete, and then remove the earth. This is extremely effective with unskilled labor, and produces beautiful, durable buildings. Another way (invented by Christopher Alexander) is to construct hollow pillars and an inner vault surface of flimsy, good-looking surfacing materials (pretty wood paneling or gypsum board). These also include the internal rebar, anchor studs, ducting, and piping. Then, these are filled with low density concrete, usually made with pumice or zeolite in place of silica gravel, and possibly with the addition of glass bottles (which are even lower density). The result is improvisable (the early stages are more like constructing a stage set than real construction), sturdy and attractive. Further, no wood, steel or other scarce materials are required for construction up to three stories tall. Examples Special cases | ||||||||||
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