Robustness of structures, 8th semester, ADS

Summary

  • According to EN 1991-1-7, Robustness is defined as ”The ability of a structure to withstand events like fire, explosions, impact or the consequences of human error, without being damaged to an extent disproportionate to the original cause”.
  • Structural robustness is therefore a matter of capacity of a structure to limit the propagation of damage (progressive collapse) after a change in the structure (e.g. initial failure).
  • The most critical elements in a building structure (i.e. whose failure will have highest consequences) are vertical load-bearing components (columns, walls). To avoid disproportionate collapse, loads should be transferred through alternative routes to still-in place elements. In the case of framed buildings, such alternatives can be created by:
    • Bending of the beam
    • Vierendeel behavior of the frame
    • Arch effect of the beams
    • Catenary/membrane behavior of beams/slabs,
  • If these alternative paths are not available, disproportionate (or progressive) collapse may be inevitable under an unforeseen event.

Objectives

  • Understanding and awareness of the role of structural robustness
  • Application of modern approaches to design new structures / upgrade existing ones for increasing robustness
  • Threat independent and threat dependent methods
  • Development of engineering judgment to rely on in the conceptual design stage (integrated design, including robustness)

Lecture notes

Robustness

Dynamics

Blast

Applications

  • Tying method approach
  • Direct method computation for vehicle impact
  • Structural assessment for column removal scenarios (Alternate Load Path) using static and dynamic analysis

Resources

Column loss – 1 column, internal

Column loss – 2 columns, external

External explosion

Internal explosion