Triple Pendulum Isolators: A New Answer Preventing Earthquake Structure Collapse

Mother Nature has been in full force lately with disasters coming one after another. While the eyes of the world have been on the oil spill, both with the clean-up and the attempts to stop the flow of oil, I have been intrigued with the new architectural advancements claiming solutions to the crumbles and tumbles of an earthquake.

At UC Berkeley Pacific Earthquake Engineering Research Center, a very large table was created that simulates the violent motion and shaking that occurs during an earthquake. Of course each resultant earthquake comes with its own prevention solutions depending on the geographic location. This being said, there remains common factors among earthquake sites including for example, infra-structure, with high-rise buildings and suspended highways which are prevalent in most large cities.

For Berkeley, and California specifically, their immediate need is in establishing designs for earthquake proof structures so that they withstand seismic motion and resultant structural collapse leading to death and major destruction. While most architectural designs that include materials for withstanding disaster such as earthquakes are priced out-side the scope of a family's budget it is governmentally sound building practices to, in all new erections, support and fund for the inclusion of energy efficiency and earthquake preparedness.

What the Pacific Earthquake Engineering Research Center is providing, as I see it, is validity of design success and as a result may offer the possibility that all building materials will become earthquake proof and might then become affordable to all builders. The other service being provided is concrete testing prior to inclusion in massive structures. This desired outcome of this research is to gain highways that don't crack and structures that don't collapse with large seismic movement.

In the earthquake research lab, on the 'shaker table' is a 30-foot, scale model bridge. The design being tested allowed for three segments jointed together which violently shook like an actual bridge if an earthquake were occurring. The bridge withstood the motion without collapse. Similar success was witnessed on a train remaining on its tracks.

So what has provided success in these sample tests? The structures have been designed with 'isolators'. The idea of segmented bridges with seismic isolators located between the segments would show, in particular, great promise with freeways that are elevated and high-speed rail lines. The architectural idea is that bending is okay replacing the breaking of the past.

Another design implementation has been with 'lock-up guides' that act to hold together and keep a-lined the structure so although much movement takes place the guide aligning the structure remains intact. The next devices are called 'linear isolators'. The linear isolators, which are coated Teflon, are placed on the abutments of a bridge and allow the bridge itself to slide in any direction. This allows for an earthquakes initial movement causing the bridge movement in any direction.

The third actual new idea is located on each column that supports the bridge. The 'triple pendulum isolator' equipped on each column becomes activated automatically one a time, if needed, as increased shaking from an earthquake continues.

All three mechanisms are in testing and it is expected that these and other new technologies will save not only structures but many lives in the future.

Sources:

San Fransico Chronicle

Triple Pendulum Isolators