An Evaluation of the Earthquake Loading Capacity of Rammed Earth Walls

Abstract

Rammed earth construction has recently regained popularity around the world as a sustainable building alternative to traditional concrete. In the past few years, several studies have researched the effects of earthquakes on rammed earth through computer simulations and controlled laboratory testing. This project introduces a new, much simpler analysis method to model the overturning collapse mechanism of a rammed earth wall, and evaluate the lateral loading capacity of such walls. Physical testing was carried out to examine the accuracy of the theory that was first discussed. A material analysis and soil characterization of the earth used during testing at Princeton University was examined to find the ultimate compressive strength as well as its optimum water content. In the final phase of the project, a research trip to Nepal was conducted to build a rammed earth wall in partnership with a local organization. An overturning collapse system was also constructed on site to display the simplicity of such a test in a developing region. The results of these experiments confirmed the manner of lateral collapse of a rammed earth wall. However, without precise quantitative measurements to verify the predicted force at the point of overturning, further testing needs to be carried out to confidently apply the theory. In future research, additional modifications should also be made to the theory to accommodate many of the reinforcement technologies that exist in rammed earth buildings in Nepal. Rammed earth has the opportunity to solve the major housing crisis this planet will face in the near future. Understanding the behavior of the material when subjected to earthquakes will be crucial in developing a more rigorous building standard to better design rammed earth structures in the future.