Yes, sorry, I got my -ium's mixed up.

I doubt you could ever make an aircraft able to withstand even the most catastrophic failure of a component. If you consider contained vs. uncontained engine failures for example.

All aviation safety is a tradeoff between idealism and realism. I imagine Concorde designers did a risk assessment: what are we most likely to find on a runway, and let's design to withstand running over it. If they considered hitting titanium rather than aluminium such a remote possibility as to not design for it, then an aircraft that dropped a piece of titanium in front of Concorde would have put it in danger.

Now, you could argue that this is simple bad luck, and most aircraft accidents are caused by the exceeding of design limits (e.g. AA587). However, in the case of this accident, this titanium strip legally should not have been on the runway. Presumably then, there is a legal avenue to explore.

I think the crux of this issue is that accidents are a chain of events. Out of the significant actors in this tragedy, only CO can be blamed. The crew, despite shutting down a good engine, could not have saved the aircraft. Air France did not load the aircraft incorrectly or maintain it incorrectly. CDG, in common with other major airports, cannot be expected to sweep runways after every departure. ATC and Met did not give inaccurate wind directions and runway assignments. Finally, Airbus designed the aircraft to certified (by the FAA) limits that were only broken due to the installation of an illegal part by.....Continental.