Structural design for: Strength, Stiffness, Stability, Synergy

Structures must be designed to satisfy three Ss and should satisfy all four Ss of structural design – as demonstrated on the following examples, illustrated at left.

1  Strength to prevent breaking
2  Stiffness to prevent excessive deformation
3  Stability to prevent collapse
4  Synergy to reinforce architectural design, described on two examples:

  Pragmatic example: Beam composed of wooden boards
  Philosophical example: Auditorium design

Comparing beams of wooden boards, b = 12” wide and d = 1”deep, each.  Stiffness is  defined by the Moment of Inertia, I = b d^3/12




Note:  The same amount of material is 100 times stiffer and 10 times stronger when glued  together to transfer shear and thereby engage top and bottom fibers in compression and  tension (a system, greater than the sum of its parts).  On a philosophical level, structures  can strengthen architectural design as shown on the example of an auditorium:

•  Architecturally, columns define the circulation
•  Structurally, column location reduces bending in roof beams over 500% !