Basket-handle arch

A basket-handle arch (also depressed arch or chop arch) is characterized by an intrados profile formed by a sequence of circular arcs, each tangent to its neighbors, resulting in a smooth transition between arcs. The shape of a basket-handle arch resembles but is different from that of a semi-ellipse, with the latter featuring a continuous curvature that varies from the extremities of the long axis to the apex of the short axis.

The simplest form, a three-centered arch, consists of three arc segments with distinct centers, while a five-centered arch is also commonly used. This type of arch is prevalent in architectural applications, particularly in bridge construction. Arches following curves with more than three centers are also used.

History

Since Roman times, bridges vaults have been built with semicircular arches, forming a complete half-circumference. From the early Middle Ages onwards, the segmental arch, an incomplete half-circumference, was used to build vaults that were less than half the height of their opening.

The pointed arch, which emphasizes height by rising above half the opening, did not see use in bridge construction until the Middle Ages.

The basket-handle arch appeared at the beginning of the Renaissance, offering aesthetic advantages over segmental vaults, notably through its end arches being vertically tangential to the supports.

The earliest applications of basket-handle arches in France can be seen in the Pont-Neuf in Toulouse, constructed in the 16th century, and the Pont Royal in the following century.