3460 Module 2

Stress

compression, tension, shear, torsion, bending

which loads are axial

compression and tension

dead loads

structural elements, fixtures, footings

live loads

occupants, furniture, storage, vehicles

environment loads

thermal expansion, snow/ice/rain, seismic, wind

Good design

firmness, commodity, delight

E words

• Efficient

  • material utilization

  • durability

  • availability

  • constructability

• effective

  • strength

  • stiffness

  • stability

  • suitability

• expressive

  • formal intent

  • spatial correspondence

  • structural responsiveness

5 S words

strength, stiffness, stability, suitability, shape

strength

the ability of a structure to resist forces without breaking

stiffness

the resistance of a structure to deformation under applied loads

stability

the capacity of a structure to maintian equilibrium and resist collapse

suitability

the appropriateness of a structural system for its intended function and design

shape

the geometric form of a structure, influencing its load distribution and efficiency

Structural typologies

section, vector, form, surface, frame

section

resisted through mass of materials and sectional qualities of component

vector

resisted throguh specific arrangement of structural components

form

resisted through form

surface

stress are resisted through their surface membrane

frame

stresses are resisted through interconnected members of components

What do stiffness and stability pertain to?

external and internal constraints

external constraints

code and legal constraints, form/volume/scale, site & environmental constraints, program

internal constraints

modules and organization, spatial organization, grid

load collector

a spanning element, collects and transfers loads

load grounder

transfers load to stable support

load stabilizer

elements that keep the structure stable

Arch failures

thrust failure, foundation arch, tie back, buttressed arch + additional weight, arches in series + buttresses

Stress

Allowable stress (Fa) = Force (P)/ cross sectional area (A)

Strain

elongation(e) = Load(P) x initial length(L) / Area(A) x Stiffness (E)

Youngs Modulus

elasticity(E) = stress(f) / Strain (s)