Capital

A capital, sütun başlığı in Turkish, sits at the top of a column shaft and transfers the load of the arch, beam or lintel above into the shaft. Its form varies widely with period and style, which makes it one of the details most often used to identify and date a building.

How the load travels

A column shaft is narrow, while the arch or beam resting on it is wide. The capital bridges the two: it collects the broad load above and directs it into the narrower shaft. In arcaded systems an impost block or abacus is often placed on the capital, and the springers of the arches sit on that block. In this way the capital passes both the vertical load and the thrust of the arches evenly into the column.

Capitals in Turkish and Byzantine architecture

• Classical orders: Doric, Ionic and Corinthian
• Basket and impost capitals: common in Byzantine buildings
• Muqarnas capital: decorated with tiers of muqarnas, in Seljuk and Ottoman buildings
• Lozenge capital, baklavalı başlık: Ottoman, with faceted triangular surfaces

Many buildings in Anatolia reuse capitals taken from older structures as spolia. That means a survey should also check whether a capital actually matches its shaft.

Survey and 3D modeling

Because of its dense detail, a capital is one of the most demanding elements to survey. High-resolution data from photogrammetry or laser scanning records carved detail accurately. In a 3D model, building the capital as a single detailed component, and keeping capitals of the same type separate with their measured differences, pays off in restitution and visualization alike. Those records become the basis for completing missing parts.