Structures Module 1: Introductory Principles

Form Active Structures

Structures whose form responds to the applied force (This is like the cables of a suspension bridge, where the sag of the main cable responds to the weight of the bridge deck. If more force is applied to one part of the bridge, the geometry of the cable will change.)

laminated timber

engineered wood products made by bonding multiple layers of smaller wood pieces or veneers together with structural adhesives

Vector Active Structures

Structures that utilize triangulation and depth to resist and effect force (The shape of the structure can be independent of loading, provided the geometry is triangulated. Action primarily in tension and compression, and members are linear elements connected at joints)

Geodesic domes

A spherical or partial-spherical structural frame made of interlocking triangles that distribute stress evenly across the entire building

Icosahedron

A three-dimensional geometric shape that has 20 flat faces

Polyhedron

A three-dimensional geometric solid made entirely of flat polygonal faces, straight edges, and sharp corners called vertices

Section Active Structures

Structures that utilize cross-sectional area and geometry to resist bending moments and shear forces

Strut

A structural bar or rod that resists compression

Vierendeel Structure

a rigid frame truss made with rectangular openings instead of the classic triangles used in regular trusses

Type: Surface Active Structures

Thin structures that transmit forces in the direction of its surface plane

Pier

a raised structure built out over water on pillars or piles, or a vertical architectural support in a building

Strain

the measure of how much an object deforms or changes shape when a force is applied to it

Stress

the internal restoring force per unit area that develops inside a material when an external deforming force is applied

Strength

A material’s capacity to withstand an applied load without structural failure or permanent collapse.

Stiffness

A material's resistance to elastic (temporary) deformation. While strength prevents a building from breaking, stiffness prevents it from bending or flexing under everyday use

Ductility

The ability of a material to deform plastically (stretch or bend) under tensile stress before it actually cracks or breaks. It is the exact opposite of brittleness.

Creep Resistance

Creep is the slow, permanent, continuous deformation of a material under a constant, long-term load—even if that load is well below the material's breaking point.

Fatigue Resistance

Resistance to progressive structural damage that occurs when a material is subjected to repeated, cyclical loading and unloading over time.

Durability

The ability of a material to resist weathering, chemical attack, abrasion, and moisture degradation over its entire intended lifespan.

Isotropy

Having identical physical and mechanical properties in all directions.

Thermal Stability

A material's ability to retain its mechanical properties (strength, shape, size) across significant temperature fluctuations.

Resistance to Fire

The length of time a material or structural assembly can withstand exposure to fire without losing its load-bearing capabilities, letting smoke pass, or bursting into flames.

Reliability

The statistical probability that a material will perform its required structural function under specified conditions without failing for a set period.

Sustainability

The environmental footprint of a material, evaluating its raw extraction, manufacturing energy (embodied carbon), lifespan, and ultimate recyclability.

Economy

The financial viability of a material, balancing the upfront purchase and labor costs against long-term maintenance savings.

Principal Stress

the maximum or minimum normal stress that acts on a plane where the shear stress is completely zero

Isostatic Lines

curves that show the direction of principal stresses at every point within a loaded structural member or material