In celebration of earth day, we want to show you the explorations of earth construction at the Form Finding Lab, in particular our focus on rammed earth. Rammed earth buildings are constructed by pouring soil into a form work, similar to the one used to make concrete elements. This soil is then compacted in successive layers, either by hand or using tampers to create highly compacted dirt walls like those in the Tuscon Mountain house.
For his senior thesis, Aaron Katz (’16) studied rammed earth buildings and the earthquake loading capacity of rammed earth walls. His research project evaluated the application of limit state analysis developed for masonry to assess the overturning of rammed earth walls during earthquakes.
A soil analysis and field tests of rammed earth were conducted on campus at Princeton and then taken across the world to Nepal. In Nepal, Aaron worked with local construction companies to test the overturning theory and learn more about the state of rammed earth building in the country. In 2015, two disastrous earthquakes struck Nepal causing tremendous damage. However, this also offered an opportunity to conduct research on the behavior of these structures that had been subjected to those earthquakes. In collaboration with construction firms and grassroots organizations dedicated to spreading rammed earth in the region, Aaron’s field tests and research will help support the local push to promote the viability of rammed earth construction in remotes areas of Nepal.
At the same time, rammed earth has been attracting renewed attention in the United States for its low environmental impact. Soil for rammed earth construction can typically be amassed on site, and requires only a minimal amount of energy to be processed into walls. This is in contrast with energy consuming materials such as concrete, steel or fired bricks. Initial tests with Princeton soil were conducted over summer 2015 by PhD candidate Tim Michiels in collaboration with the Laura Salazar from the SoA’s CHAOS lab.
Photos of the rammed earth experiments over summer 2015 on Princeton campus. (photo credit: Tim Michiels)
Another, larger construction project of a rammed earth sculpture in Forbes Garden will soon kick off as well (click for more info). This sculpture will demonstrate the feasibility and durability of construction rammed earth walls from local, unstabilized Princeton soil. Stay tuned for more updates on our earth construction endeavors and happy earth day!
Authors: Aaron Katz and Tim Michiels