Removing a pile of debris is like the game of pick-up-sticks where you lose if a stick moves. Only with roof debris your “loss” might be an injury possibly a serious one to yourself or the survivors you’re seeking.
Professional engineers know about supporting and holding things up properly. That’s what structural engineering is all about. Having a forensic structural engineer on the first response team would seem to be a good idea. They are going to be involved in any event determining the cause of the collapse.
Good response leadership – which was lacking at the Elliot Lake roof collapse according to an editorial in Saturday’s Globe and Mail, needs good advice. What better place to get it than from people who design things to stand up?
Swift action involving engineers is also needed because so much of the evidence associated with a collapse is of a perishable nature – some of it highly perishable. Steel and concrete fracture surfaces will corrode and weather, debris will be moved and memories will fade.
The first steps in the forensic structural engineering investigation of a collapse are critical and concerned with safety in the debris, the “pile of sticks” that the debris is not at all unlike. They may also profoundly influence the success of subsequent forensic technical investigations.
The engineer may be requested to assess the safety and stability of a structure for a variety of possible reasons:
- To assist in identifying the safest routes through the debris, or identifying areas that must be avoided until stabilized
- To assist in identifying components that are in imminent danger of further collapse.
- To evaluate methods of stabilizing the structure.
- To assist in determining whether it is advisable to provide protection for the public.
- To assist in evaluating alternative demolition or dismantling sequences.
An argument could even be made for having the first response team to a collapse site headed up and directed by a professional engineer with a project management background.
References
The Globe and Mail, Saturday, June 30, 2012, page F8 Comment.
Ratay, Robert T., Forensic Structural Engineering Handbook, Chap. 4, The First Steps After a Failure, McGraw Hill, 2000