The rocket stabilizing technology engineered by NASA scientists provides a new means of preventing tall buildings from swaying during periods of high winds and reducing shaking during earthquakes.
The BKYLN B2 Tower in Brooklyn, New York is the first skyscraper to use NASA’s innovative stabilizing technology. Source: Aidan Wakely-Mulroney
As populations migrate to urban centers and real estate in U.S. cities becomes scarce and expensive, building construction is moving up to the skies as opposed to the suburbs. While skyscrapers form iconic skylines, they also pose challenges in terms of stability. For example, people tend to feel uncomfortable when they are in a building that sways during windy days. Additionally, tall buildings can be especially vulnerable to structural damage during earthquakes.
While most people associate earthquake hazards to West Coast cities like Los Angeles and San Francisco, FEMA reports that 20 states are at moderate to high risk of experiencing an earthquake that causes significant damage. For example, the New Madrid seismic zone, located in the Mississippi River Valley, produced a series of earthquakes with estimated magnitudes of at least 7 on the Richter scale during the early 19th century. While this fault area remained relatively quiet during the 20th century, recently, the zone shows signs of becoming more active. Fortunately, robust building codes, along with the application of state of the art engineering and construction practices, can significantly reduce the risk to life and property caused by building collapses during earthquakes.
Tuned Mass Dampers: Stability at a Cost
Currently, engineers use Tuned Mass Dampers (TMD) to stabilize tall buildings to prevent movement of the structure due to high winds and to provide resilience during earthquakes. These systems use massive weights to counteract any movement in the building. The TMD in the Comcast Center, which is the tallest building in Philadelphia, uses a tank filled with 300,000 gallons of water that acts a counterweight to any movement. The video below shows the 730-ton ball used in the TMD of the Taipei 101 skyscraper in Taiwan moving to stabilize the structure against 130 mph winds that occurred in August 2015 during Typhoon Soudelor.
The 730-pound gold ball moving to stabilize the Taipei 101 skyscraper during 130 mph winds. Watch the video here.
While TMDs prove effective as a means of stabilizing skyscrapers, they do have drawbacks. First, they tend to be expensive to construct. Secondly, TMDs require a significant amount of space, which is scarce in urban markets. Surprisingly, NASA scientists found a low cost and space efficient stabilizing technology that they adapted for use in tall city buildings.
NASA’s Rocket Stabilizing Technology Adapted for Use in Skyscrapers
During tests of the Ares rocket in 2013, NASA scientists discovered that the rocket’s violent shaking would pose a danger to astronauts if it was used to launch a manned spacecraft. Unlike skyscrapers, a weighted damper system does not work for rockets and spacecraft because the weight would prevent the Ares from lifting off the launch pad. NASA engineers needed to find a different means of quelling the rocket’s excessive shaking.
The NASA team decided to focus on the fuel used to power the rocket. By matching the vibration of the fuel with that of the 650,000 rocket, the engineers eliminated the dangerous shaking that posed a safety risk to astronauts. The device, called an LOX damper, weighed in at a mere 100 pounds, but decreased the shaking of the rocket by 20 fold.
Diagram of LOX Bellows Design. Source: NASA Spaceflight Forums
While working on the LOX damper system, the NASA engineers realized this same system, with adaptation, could also serve to stabilize buildings. As objects with a set mass and stiffness, buildings naturally vibrate at a set frequency. By using a device that created a vibration matching the structure’s natural frequency, the building would resist swaying during high winds or earthquake. The technology they created, called a Disruptive Tuned Mass (DTM) device or a Fluid Harmonic Disruptor, was about the same size as a coffee can. Since the device could be installed in a swimming pool or the building’s water system, the stabilizer system did not require a significant amount of space.
Brooklyn Tower: First Application of NASA
The first building to use the NASA-designed system is the B2 Tower in Pacific Park development located in Brooklyn, NY. The stabilizer engineered for this building uses six PVC tubes filled with water installed on top of the 32 story building. The fluid harmonic disruptor maintains a vibration within the water-filled that matches that of the building. The B2 engineers chose to use the new technology since the modular design of the tower makes it very lightweight with the maximum unit weighing 24 tons. As such, the two TMDs for this structure would need to be 100 tons, making this type of stabilizer much more expensive than the fluid harmonic disruptor. While NASA team engineered the B2 system to keep the tower stable during periods of high winds, they anticipate the success of the new technology will lead to other engineers and architects including DTM devices in skyscrapers in cities at risk of damaging earthquakes.
What do you think about this new technology? Would you include it a skyscraper you designed?