Update: Where does an expert’s initial hypothesis come from?

I commented last month on the basis for an expert’s hypothesis during the merit assessment stage and gave a few examples. (Ref. 1) You may remember that the hypothesis or initial oral report comes from:

  1. Your briefing
  2. The expert’s experience
  3. Published data on causes

The examples of published data were quite informative. (Refs 2, 3, 4) The most detailed was about the 209 ways a building can fail – useful information and readily available to the expert when assessing cause. (Ref. 2)

There’s more.  A building is only one type of structure in the built environment.  There are actually about 18 different types as listed below. (after Ref. 4)  Each structure can fail in several different ways.  The causes have been researched and published for most of the 18 like the 209 causes for a building.

(It was Ref. 4 that prompted this blog update – it extends our understanding of failure and accidents to all types of structure)

Your urban environment where you live contains some or all of the following types of structure:

  1. Bridges
  2. Dams
  3. Tunnels
  4. Highways
  5. Embankments
  6. Excavations
  7. Natural, and man-made fill slopes
  8. Multi-story buildings
  9. Industrial buildings
  10. Residential buildings
  11. Foundations
  12. Basements
  13. Retaining walls
  14. Infra structures
  15. Tanks
  16. Storage bins
  17. Chimneys and stacks
  18. Towers; both guyed and free standing

The causes of failure of these structures are categorized according to the:

  • Structure - those listed above and again in the Appendix
  • Main Component in the structure – beam and slab, an arch, long span roof, etc
  • The component’s Material - steel, concrete, wood, masonry, etc.

The categorization is more detailed and technical than this but the above gives you an idea..

(The Appendix lists the different structures, their components and component materials)

The researchers identified the several different ways each Structure can fail.  For example, What causes bridges to fall down?  Towers to topple?  Multistory buildings to settle?

They then looked closer at the main Component(s) in each structure and identified the different ways these failed.  For example, What are the different causes of cracks in concrete floor slabs?  Why do roofs collapse?

Finally, they looked closer still at the different Materials used in the components of structures and how they failed.  Why does steel break?  It certainly does at times.  What causes concrete-wood connections to come apart?

The result is a wealth of published information for the expert to consider when forming a hypothesis – 100s of different ways a structure, it’s components, and the component’s materials can fail in the built environment.  All researched and published and available to guide the expert as you brief him during the merit assessment stage.

He’s thinking Structure, Component, Material as you talk and forming an initial hypothesis, or, more correctly, an initial oral report to guide you on whether to take the case or in assessing the claim.  It might be a rough report but it’s well founded on a lot of published data – and better than not talking to an expert.

(It occurs to me this late hour that similar data could be compiled and published on the causes of personal injury accidents like slip, trip and fall accidents)

References

  1. Where does an expert’s initial hypothesis come from?  Posted February 25, 2019
  2. Nicastro, David H., ed., Failure Mechanisms in Building Construction, ASCE Press, American Society of Civil Engineers, Reston, Virginia 1997 (Readily available by interlibrary loan from Memorial University, Newfoundland)
  3. How many ways can a building fail, and possibly result in civil litigation or an insurance claim? Posted July 10, 2014
  4. Janney, Jack R., Guide to Investigation of Structural Failures, ASCE (American Society of Civil Engineers) 1979, 1986

Appendix

(The following lists are after Ref. 4 with some additions based on what I’ve seen over the years)

Structure: Causes of failure have been researched and identified according to the following types of structure:

  1. Bridges
  2. Dams
  3. Tunnels
  4. Highways
  5. Embankments
  6. Excavations
  7. Natural, and man-made fill slopes
  8. Multi-story buildings
  9. Industrial buildings
  10. Residential buildings
  11. Foundations
  12. Basements
  13. Retaining walls
  14. Infra structures
  15. Tanks
  16. Storage bins
  17. Chimneys and stacks
  18. Towers; both guyed and free standing

Component: Causes of failure have been researched and identified according to the main types of components in the different structures

  1. Arches, rigid frames and trusses
  2. Suspension structures
  3. Long-span roofs
  4. Beam/Slab combinations
  5. Flat plate and flat slab
  6. Multistory rigid frames
  7. Thin shells and membranes
  8. Cantilevers

Material: Causes of failure have been researched and identified according to the materials used to make the different components in the structures, and the connections between the materials

  1. Steel
  2. Concrete
  3. Masonry (structural clay and concrete block)
  4. Wood
  5. Plastic
  6. Failure causes classified by connection type
  7. Steel to steel connections
  8. Steel to concrete composite connections
  9. Monolithic concrete member intersections
  10. Precast concrete to precast concrete connections
  11. Pre-stressed concrete
  12. Masonry connectors
  13. Timber fasteners and adhesives
  14. Expansion type connections

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