Shell structures offer a unique and innovative approach to building design. They are lightweight constructions that provide a high degree of structural efficiency through the use of curved surfaces.
Shell structures are designed to distribute loads evenly while minimizing the amount of material used, making them a sustainable and cost-effective option for construction.
What are Shell Structures?
Shell structures are unique structural systems that derive their strength from their shape. They are curved, thin surfaces or shells that are supported by a series of columns or other structural elements.
Advantages of Shell Structures
Ability to span large distances without additional support
Can be constructed using environmentally-friendly materials
Unique and dynamic shapes
Disadvantages of Shell Structures
They can be difficult to construct and require a high level of precision.
The curved surface can make it challenging to install windows and other features.
Types of Shell Structures
Thin shell structures
1. Geodesic Domes
A geodesic dome is a type of shell structure made up of a network of triangles arranged to form a sphere or dome-shaped structure. The structure is then covered with a skin or cladding material. Geodesic domes are often because they are lightweight, strong, and can span large distances without the need for additional support.
Epcot Center, Florida
Designed by Buckminster Fuller, the most iconic structural feature of Epcot is the geodesic sphere known as Spaceship Earth.
Structure: It is made up of 11,324 triangular aluminum-alloy panels and is held together by a network of tensioned cables.
Shape: The sphere’s shape distributes the structural loads evenly, allowing for its impressive size and stability.
2. Thin-Shell Structures
A thin-shell structure is a type of shell structure made up of a thin, curved surface, often made of concrete or other materials that can be molded into shape. Thin-shell structures are often used in architecture because they are lightweight, strong, and can span large distances without the need for additional support.
Sydney Opera House, Australia
Designed by the Danish architect Jørn Utzon, the Sydney Opera House features a series of distinctive shell-like structures that cover its main performance halls and create its iconic silhouette.
Construction Method: The shells are constructed using a technique called precast concrete ribbing
Structure: A series of concrete segments are connected together to form the curved and interlocking shell shapes.
3. Tensegrity Structures
A tensegrity structure is a type of shell structure made up of a network of tensioned cables or rods. These cables or rods are arranged to form a complex, three-dimensional structure that is both strong and lightweight. Tensegrity structures are often used in architecture because they can create unique and striking designs.
Denver Art Museum, Colorado
Designed by Daniel Libeskind, this museum stands out for its angular and deconstructivist design.
Form: This museum features a series of interconnected steel tubes.
Structure: It consists of a series of geometric volumes that appear to jut out from the central core, creating a dramatic and dynamic visual effect.
Angular Shape: The sharp angles and irregular forms of the building are characteristic of Libeskind’s architectural style.
4. Catenary Structures
Catenary structures are architectural or engineering forms that follow the shape of a catenary curve, which is the natural curve that a flexible chain or cable assumes under its own weight when suspended between two points.
Mercedes Benz Stadium, HOK Architects
The catenary-inspired feature in the Mercedes-Benz Stadium is its retractable roof, which consists of eight triangular roof petals. When fully open, these petals resemble the shape of a blooming flower.
Structure: Each of these roof petals is supported by an intricate network of steel cables and a central steel compression ring.
Innovative Design: This design allows the roof to retract and close like a camera aperture.
5. Membrane structures
Membrane structures are lightweight, flexible, and often translucent or transparent forms that use a combination of tensioned membranes and a supporting structure to create a wide range of shapes and spaces. These structures are widely used for their efficiency and versatility.
The Eden Project
The Eden Project consists of several biome domes, each representing a specific climate zone, such as a rainforest biome or a Mediterranean biome.
Building material: The domes are constructed using a combination of steel frames and ETFE (ethylene tetrafluoroethylene) foil cushions as the transparent membrane material.
Sustainable: These tensioned membranes allow for natural light to enter the structures, creating a suitable environment for the plants within.
Grid shell structures are forms that consist of a three-dimensional grid or lattice-like framework that is designed to support loads while achieving a desired shape.
These structures are characterized by their ability to distribute forces evenly throughout the grid, making them efficient for spanning large areas with minimal material use. Grid shells are often used to create curved and complex geometries that might be difficult or expensive to achieve with traditional building methods.
Sainsbury Center for Visual Arts, Norwich
Designed by Norman Foster, the most prominent feature of the Sainsbury Centre is its grid shell roof.
Structure: It covers the main exhibition space and features a striking lattice of steel beams and tension cables.
Roof usage: The grid shell creates a sense of openness and transparency while providing structural support.
Roof characteristics: The grid shell’s design allows for large, curved expanses of glazing, giving the building a sense of lightness and transparency.