The big idea for this episode is to discuss the FIU Bridge Collapse with Gary Klein of Wiss, Janney, Elstner Associates (WJE). Mr. Klein takes exception to the NTSB/FHWA findings.
This episode is technical, detailed, and assumes the listener has a general knowledge of the FIU bridge and collapse investigation. For a more general introduction to the FIU Bridge, please see Collapse of the FIU Pedestrian Bridge, Episode 1.
Much of this conversation follows along with a presentation that Mr. Klein delivered to the AASHTO Committee on Construction 2020 annual meeting.
For full show notes, see Build Big Ideas - Gary Klein of WJE: FIU Bridge Collapse and Exceptions to the NTSB Findings, Ep. 11.
Outline and Notes of the Podcast Discussion
Brief intro to Gary Klein career and qualifications - National Academy of Engineering member - WJE has a massive structural laboratory, not just computers and pencils - Expert witness experience: Hyatt Regency, Boston Central Artery, and more
WJE exceptions to NTSB/FHWA findings - What is the role and incentives for an expert witness? - Obviously, you are committed to facts. Do you strive for impartiality? - Are NTSB, FHWA, and AASHTO aware of the WJE exceptions? Have they provided specific responses?
Redundancy: internal, structural, load path - Was the designer responsible for checking the construction sequences?
Interface shear transfer testing - Why not conservatively design the connection with enough shear reinforcement steel instead of relying on cohesion at a cold joint? - Is any structure ever constructed perfectly to spec? - Was the cold joint always intended during design, or added later during construction?
Load factors and safety factors under dead load during construction - Was the AASHTO code really relevant to a concrete truss member?
Lessons learned: EOR onsite, joint inspection, traffic closures for safety
References
Wiss, Janney, Elstner Associates (WJE) materials:
National Transportation Safety Board (NTSB) materials:
Threads to pull for future episodes
What are the human stories that preceded the collapse?
What thoughts do other knowledgeable people have about the collapse?