**Basic Concepts and Classification**:
– A true arch is a load-bearing arc held together by compression.
– False arches are non-structural and used for decoration.
– Elements of a masonry arch include keystone, voussoir, extrados, impost, intrados, rise, clear span, abutment, spandrel, arc, and arcature.
– Archivolt is the front-facing part of the arch.
– Arches can be classified by intrados shape, number of circle segments, and construction material.
– Different construction approaches include cutting regular bricks or using wedge-shaped bricks.
– Stone arches usually have no hinges, while bridge spans may have hinges.
– Romans perfected the arcade form seen in structures like Pont du Gard.
**Arch Action and Structural Aspects**:
– A true arch resolves vertical loads into horizontal and vertical reactions.
– Elements in a loaded arch are mostly subject to compression.
– Counter-arches were historically used to counteract horizontal forces.
– New construction materials have made arches lighter and reduced the need for heavy abutments.
– Ties connecting arch ends can further relieve horizontal thrust.
– Relieving arches redistribute load in buildings.
– Transverse arches compartmentalize internal space.
– Diaphragm arches support high roofs.
– Strainer arches prevent support collapse.
– Counter-arch stabilizes adjacent arches.
**Funicular Shapes and Arrangements**:
– Compression-only arches and tension-only hanging chains share symmetry.
– Arch shapes are studied in comparison to hanging chains and flexible tension-only designs.
– Arch shapes vary based on weight distribution, similar to hanging chains.
– Arcades are a sequence of arches perfected by the Romans.
– Separating arches divide spaces like in hall churches.
– Two-tiered arches are used in Islamic architecture for decoration.
– Blind arches are decorative and found in Early Christian, Romanesque, and Islamic architecture.
– Containing arches are created by filling openings with smaller arches.
**Shapes and Subtypes**:
– Arch shapes include rounded, pointed, and parabolic variations.
– Rounded arches are common in Roman, Romanesque, and Renaissance architecture.
– Pointed arches come in various styles like equilateral, blunt, and lancet.
– Subtypes of arches include relieving, transverse, and diaphragm arches.
– Segmental arches are used in Greek temples, Islamic architecture, and Renaissance styles.
– Horseshoe arches are common in Islamic-influenced regions.
**Specific Arch Shapes**:
– Rounded arches: semicircular, segmental, horseshoe.
– Segmental arches are used in Greek temples and Islamic architecture.
– Basket arches are seen in late Gothic and Baroque styles.
– Horseshoe arches are common in Islamic-influenced regions.
– Semicircular arches are used in Great Wall construction.
– Pointed arches offer architectural diversity with styles like equilateral, blunt, lancet.
– Ogee and four-centred pointed arches add visual interest.
– Curtain and pointed horseshoe arches provide unique designs.
An arch is a curved vertical structure spanning an open space underneath it. Arch can either support the load above it or perform a purely decorative role. The arch dates back to fourth millennium BC, but became popular only after its adoption by the Romans in the 4th century BC.
Arch-like structures can be horizontal, like an arch dam that withstands the horizontal hydrostatic pressure load. Arches are used as supports for many types of vaults, with the barrel vault in particular being a continuous arch. Extensive use of arches and vaults characterizes an arcuated construction, as opposed to the trabeated system, where, like in the architectures of ancient Greece, China, and Japan (as well as the modern steel-framed technique), posts and beams dominate.
Arches had several advantages over the lintel, especially in the masonry construction: with the same amount of material it can have larger span, carry more weight, and can be made from smaller and thus more manageable pieces. Their role in construction was diminished in the middle of the 19th century with introduction of the wrought iron (and later steel): the high tensile strength of these new materials made long lintels possible.
Definition from ChatGPT:
Arch:
An arch is a curved structure typically spanning an opening and supporting the weight above it. Arches are commonly used in architecture and engineering to distribute loads and create aesthetically pleasing designs.