Structural Design for Architecture

Vocabulary flashcards covering core structural design concepts, types of structures, materials, loading, and key design principles from Angus Macdonald's Structural Design for Architecture.

Equilibrium

A state in which the sum of all forces and moments on a structure is zero, so the structure remains at rest under the applied loads.

Stability

The ability of a structure in equilibrium to resist small disturbances without undergoing a major change in shape or collapse.

Rigidity

The resistance of a structure to deflection; adequate rigidity limits excessive movement under loading.

Post-and-beam structure

A basic structural system with horizontal beams spanning between vertical posts/columns, typically bending in the beams under gravity.

Skeleton-frame structure

A post-and-beam system where walls are non-loadbearing and the frame carries the primary loads, allowing large open spaces.

Panel structure

A structural system in which walls or panels carry loads and floors/roofs span between them.

Vaults and domes

Compression-dominant structures with upwards-curving forms that can span large spaces, often using masonry or concrete.

Tents and cable networks

Tensile structures where axial tension in cables or membranes carries loads efficiently over long spans.

Combined-action structures

Structures in which loads are resisted by a combination of bending and axial forces, offering intermediate efficiency.

Form-active

A structure whose geometry actively resists loads, often achieving high efficiency through bending or axial action (e.g., arches, vaults, shells, cable networks).

Semi-form-active

Structures that are between form-active and non-form-active, using a mix of bending and axial forces.

Non-form-active

Structures where bending is the primary resistance mechanism, with limited axial engagement; generally less efficient for long spans.

Structure-ignored

An approach where architectural form is determined with little or no regard to structural implications.

Structure-symbolised

A design approach where the structure is visibly expressed as an architectural feature, often for technological or prestige reasons.

Structure-accepted

An integrated design approach where structure and architectural design are developed together in harmony.

True structural high-tech

A highly technical, overtly structural approach where the structure drives the form, often with extensive exposed steel or other high-tech elements.

Structure coming from material: Steel

A high-strength, light, ductile structural material used for skeleton-frame structures and long-span frames; strong in tension and compression.

Structure coming from material: Reinforced concrete

Concrete reinforced with steel, offering high compressive and tensile strength, good continuity, and mouldability for complex forms.

Structure coming from material: Masonry

Solid bricks/stones with mortar; strong in compression, weak in tension, typically used in loadbearing walls and vaults.

Structure coming from material: Timber

Lightweight, strong in both tension and compression, easily worked, but variable and sensitive to moisture and joints.

Loadbearing wall

A wall that supports gravity loads from floors and roofs, common in masonry and timber constructions.

Diaphragm bracing

A horizontal or vertical plane (floor, ceiling, or wall) that transmits lateral loads to the structural system, providing stiffness.

Two-way spanning slab

A floor slab that spans in two directions between a square or nearly square grid of columns or walls.

Flat-slab

A two-way spanning reinforced concrete slab directly supported by columns without heavy beams.

Coffered slab

A two-way slab with a grid of recesses (coffers) to reduce weight and improve stiffness.

Beam/column frame (RC/steel)

A reinforced concrete or steel skeleton consisting of beams and columns carrying floor slabs with good continuity.

Flat deck space frame (space framework)

A three-dimensional steel framework using interconnected members to form a rigid, light, and span-efficient structure.

Truss

A framework of straight members connected at joints to form a stable structure with high strength-to-weight ratio, often triangular.

Space frame

A lightweight, highly triangulated, three-dimensional truss system offering high stiffness and efficiency for large spans.

Masonry wall ratio: slenderness

The ratio of a wall’s height to its thickness, affecting buckling risk; kept low for stability.

Buckling

Instability of a slender compressive element under load, leading to sudden lateral deformation or collapse.

Euler buckling

A classical formula predicting the critical load at which a perfect column buckles: Pcr = π^2 E I / L^2.

Radius of gyration

A measure r = sqrt(I/A) that relates cross-section geometry to buckling behavior and critical load.

Slenderness ratio

Le/r (effective length over radius of gyration); determines buckling resistance and design stress.

Effective length

The length used in buckling calculations, adjusted for end restraints and support conditions.

Span

The clear distance between supports (beams or columns) that a structural element must span.

Lateral stability

Resistance to side-to-side movement, especially important for tall or slender buildings under wind or seismic loads.

Fire resistance (steel)

Ability of a steel structure to maintain stability under fire; often achieved with fireproofing or protective strategies.

Fire protection

Encasement or shielding of steel to slow temperature rise and maintain structural integrity during fire.

Precast concrete

Concrete elements cast in a factory and transported to site for assembly, enabling high quality and speed.

In situ concrete

Concrete cast directly at the building site within formwork.

Concrete strength/durability

Concrete properties: high compressive strength, variable tensile strength, good fire resistance and durability.

Reinforcement

Steel bars or meshes embedded in concrete to resist tensile stresses and improve ductility.

Mortar vs cement ratio

Proportions affecting workability, strength, shrinkage, and durability in masonry and concrete.

Diaphragm wall

A vertical-planted wall acting as lateral bracing to resist wind or seismic loads in tall masonry buildings.

Flexibility of form and material choice

Trade-off between architectural form, structural efficiency, and material properties to achieve feasible designs.