In a warehouse in Reno, scientists are putting the biggest seismic facility in the country through its paces. The newly-expanded lab earthquake lab uses three 50-tonne shake tables to simulate earthquakes — including the infamous 6.9 earthquake in Kobe, Japan.
A team of schools, led by University of Nevada at Reno, recently recreated intense earthquakes to test a new type of bridge construction at the lab. The idea was to design a bridge support system that was cheaper, stronger, and faster to build than a normal bridge — and more resistant to earthquakes. So this summer, the team built a 20 metre chunk of the system atop the lab's three hydraulically-powered shake tables — and then strapped hundreds of sensors to its tensioned concrete columns.
When everything was set up, the team put it through a battery of faux-quakes — ten in all, culminating in one designed similarly to that of the deadly Kobe quake of 1995. How did the bridge stand up? Well, it deflected a massive 12 per cent from its origin point and broke in places, but it stood standing — which is the important part. Now, they can take the sensor data and continue working on the bridge design.
One uncanny detail from the test: According to the scientists, you could actually hear the rebar moving inside the concrete during the quakes. What did it sound like? A "zipper opening." [University of Nevada at Reno]