A stilted arch is an architectural form in which the curve of the arch proper begins above the level of its imposts (the points where the arch rests on its supports). This is achieved by incorporating vertical sections, often referred to as "stilts" or "springers," between the impost and the springing line (the actual point from which the arch's curve commences).
Characteristics and Construction
The distinguishing feature of a stilted arch is the presence of these vertical elements that lift the arch's springing line. The imposts therefore mark the base of these stilts, rather than the immediate beginning of the arch's curvature. The curve itself can be semi-circular, segmental, or pointed, but its defining characteristic remains its elevated start. This construction effectively increases the height of the arch without altering its horizontal span.Purpose and Usage
Stilted arches are employed for a variety of architectural and structural reasons:- Increased Clearance: They provide greater vertical clearance beneath the arch without requiring a wider span, which can be beneficial in situations with limited horizontal space or specific height requirements.
- Aesthetic Effect: The vertical stilts can create a visual impression of greater height, slenderness, or elegance compared to a standard arch of the same span. They can also create a visual transition between vertical supports and the curve of the arch.
- Structural Integration: In some designs, the stilts help to align the arch with other structural or decorative elements, such as vaulting ribs in a nave arcade.
- Load Distribution: While not their primary purpose, the stilts can subtly influence the distribution of forces within the arch and its supports.
Historical Context and Examples
The stilted arch has been utilized in various periods and styles of architecture. It was notably a common feature in Romanesque architecture across Europe during the 11th and 12th centuries. In Romanesque churches and cathedrals, stilted arches were frequently used in nave arcades. The vertical springers helped to emphasize the verticality of the structure and could visually connect the arcade arches with the vaulting above. While less common than the pure semi-circular arch in Roman engineering, the concept of raising an arch for specific clearances or to accommodate an overall design scheme has precedents.See Also
- Arch
- Impost
- Springing line
- Romanesque architecture
- Horseshoe arch