Designing Secure Havens for the Worst of Tsunamis


[Musical Introduction] In the United States there are
a number of different codes that are out there that tell engineers how they should
design structures to remain standing. So, all members of our research team are actually on
that committee and we’re trying to get our information into it. There are a couple of empty chapters in ASCE 7 and one of
them we are now writing on Tsunami demands on structures. [no audible dialogue] [Sound of container breaking loose
and loudly banging into the wall with extreme force] The concept behind the research project
is to look at the effects of debris impact. For those people who saw the footage
from the Tohoku earthquake in Japan, from all that damage you can see a lot of the debris that
was picked up in addition to the wave effects, hydraulic effects, and hydrodynamic effects; there’s just all this mass of debris in the water. The research that we’re looking at
is how do you design for that debris. If you have all these massive pieces of houses, vehicles, and
containers coming at a structure and impacting the structure, how do you actually design that structure for that? And actually, taking a step back is
what force is actually generated by that impact. So, what we’re doing is trying to predict the forces
that are being generated by the impact events. -News Coverage- “Massive tsunami wave.” “…has issued a warning for a tsunami up to six meters deep.” ” More than 15,000 people dead.
130,000 people forced from their homes. ” ” Live coverage of the tsunami engulfing… ” ” So many fleeing to rooftops to escape
the mountain of debris barreling by. ” It was incredible to see that. The devastation was just unbelievable; you can’t imagine. Even the pictures and videos you see just don’t do it justice until
you’re standing on the ground and you look up and see a sign that’s literally maybe 60 feet tall, a big billboard sign, and only the last five feet of it is left because
the water was 40 to 50 feet above where you’re standing. It’s just incredible. Nothing is left. You have wood-frame construction that’s completely gone. It’s amazing to see this firsthand. How do we design evacuation shelters? That’s really where our focus is. We’re looking at maybe Waikiki Beach or something
where you’re going to have a lot of people out there. And, it’s flat; there’s no real elevation aside from the hotels. So, you have to design these structures to actually survive an event. So, the trick of what we’re trying to do here is come up with
the recommendations of what forces you have to design for. If you have a new region that’s being developed
that is prone to tsunami events —maybe even up in Alaska some new
development is going to be put up— then how do we design that structure? We’re looking at full size, which is difficult to do in the water. There’s no where you can really do that easily. So, we’re doing the in-air effects,
understanding how this debris works in the lab, what kind of responses it has,
and how that contributes to the demands. The whole thing is, as a researcher, you can’t test everything ; you do a few tests to develop models,
calibrate models that you’re confident that they work, and then you can do thousands of simulations
to really understand the phenomenon that’s occurring. People have made models, they make them all the time,
they still make them all the time. I’ve seen many people do just model, model, model,
and there’s not one data point that justifies whether it’s right. You can make a model and do whatever you want, so you have to have the experiments to either prove that it’s
right at the end or validate the concepts that you’re dealing with, or else it’s all just make believe.

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