Amphitheaters: Design Principles and Influences of Classical Architecture

PART 2 - CONSTRUCTION & MATERIALITY

Classical amphitheatre construction relied on specific building methods, strong stones, and complex mechanical systems. While Greek amphitheatres relied primarily on the natural landscape to support the construction of their Ampitheatres, Roman amphitheatres used advanced engineering with concrete, brick, and stone to construct larger, more complex, and more durable freestanding structures. These robust materials supported the massive weight of both the building and the crowds it accommodated, and allowed for the inclusion of underground passages and elaborate vaults.

Builders used layered arches, barrel vaults, and concrete cores to support large crowds and open spaces. Foundations were often deep and thick, ensuring stability even on varied soil types. Roman builders frequently placed amphitheatres at the center of cities, using dry-stone construction (stacking stone blocks without mortar) and securing them with iron clamps for extra strength. Openings in the outer walls, called arcades, facilitated the rapid movement of crowds. These construction techniques contributed to the remarkable durability of amphitheatres, with many, like the Colosseum, still standing today.

Travertine stone was a main material for outer walls and pillars in Roman amphitheatres. This light-colored limestone, quarried outside Rome, was strong yet easy to cut, making it ideal for shaping large blocks for arches and steps. For interior walls and vaults, builders often used brick and concrete due to their lighter weight. Seats were usually made from stone or marble and fixed in place, providing lasting comfort and stability for spectators. Strong attention was also given to the ground material in the arena itself—sand or fine gravel was commonly used to absorb spills and provide a stable, manageable surface for performances and events.

Illustration of "amphitheatri interior" from Ivsti LipsI Ad Iac

Symmetry and proportion were central to amphitheatre design and construction, serving both aesthetic and functional purposes. The entire structure was arranged around a central point, typically the middle of the arena, with all parts balanced on each side. Rows of seats were spaced evenly, maintaining consistent width and depth, while the overall height and width of the amphitheatre adhered to exact ratios. This careful attention to proportion not only created a pleasing and orderly appearance but also enhanced structural stability. Columns, arches, and podiums were placed with precision, further improving the amphitheatre’s strength and grandeur. Designers favored simple geometric shapes, mostly circles and ellipses, to guide their plans, which allowed for both beauty and robust support. The balanced design also helped distribute sound and sightlines evenly throughout the seating area, enhancing the audience experience.

Beyond their impressive scale and symmetry, classical amphitheatres often included special construction features, a complex system of machinery and hidden features beneath its arena, known as the hypogeum. This underground area included tunnels, animal cages, and chambers. Elevators and pulleys, made from wood, ropes, and metal parts, allowed workers to lift animals and scenery up to the arena floor. Trapdoors could be opened to surprise the crowd with sudden animal entries or props, adding drama and excitement to the spectacles. Although few original parts remain today, drawings and models reveal just how advanced these systems were for their time. These innovative features showcased the engineering ingenuity and creativity of ancient builders, contributing to the lasting legacy of classical amphitheatres.