Simple Building Retrofit Can Reduce Sway from Earthquakes

NASA and University of Alabama engineers are testing a disruptive tuned mass (DTM) system they say can mitigate a building’s response to earthquakes. Originally developed to solve vibration issues encountered during a rocket launch, the DTM system has potential applications across multiple industries to improve damper systems on ships, automobiles, airplanes, offshore platforms, bridges and more.

“Mitigating earthquakes in buildings is not a typical NASA mission, but the technology came from our mission. Now we want to get this out to the companies that can use this,” says Rob Berry, project manager for Disruptive Tuned Mass and Fluid Structure Coupling Technologies at NASA Marshall Space Flight Center, in Huntsville, Alabama.

Tall buildings often use systems with solid weights or shifting fluids to counteract vibrations created by earthquakes, wind or other sources by moving the mass of a building in response to vibrations. These systems—so-called "tuned mass systems"—are often expensive, bulky and can be difficult to retroactively install in older buildings.

The DTM technology, however, leverages existing or added mass, whether fluid or structural additions, to change the response characteristics of a building. Fluid-based DTMs can use any existing fluid mass in a building, including swimming pools, water tanks, sprinkler systems, standard plumbing or existing structural mass such as air-conditioning to mitigate vibrations.

The device itself, which weighs less than 200 lbs., can be placed anywhere internal or external fluids interact with physical structures and can subsequently be tuned to the frequency at which a building moves—whether due to winds or an earthquake. The effect is to help neutralize the sway of the building.