Rammed Earth Catenary Arch
Our explorations with rammed earth required us to gain a deep material understanding of this building method. Traditionally, rammed earth is used in wall or brick form; as a point of departure, we began questioning the boundaries of the conventional form. We began experimenting with shape, scale and connections to conceptualize various “modules” that could be aggregated to form a temporary rammed earth shelter. Temporality was another critical aspect for our team: we wanted the modules to be able to return completely to the earth after their use. To help naturally stabilize our rammed earth, we used separated sisal fibres.
The catenary curve, whose structural integrity performs most advantageously in compression, is an appropriate response to a material which also functions in a likewise manner – only in compression. Because a catenary curve would allow an arch to support its own weight, we understood this as the most feasible design avenue to further explore new methods of modular aggregation to create a pavilion out of rammed earth.
With the exploration of catenary arches as a module for aggregation came the realization that the arches held an aspect of adaptability, in that they could be arranged into a myriad of compositions to generate different types of spaces. To underline our most central design concept of temporality and sustainability, the formwork of one arch required detailed tectonic design, particularly in its connections and details, in order to be entirely reusable.
In our process to create one singular module, we reached some outstanding statistics. In 11 days, we used 110 dowels, 40 feet of sisal, 24 individually measured and mixed buckets of dirt, yielding an arch that weight a total of 500 pounds. Most significant of these statistics is the 16 consecutive hours it took to ram the arch with the custom tampers we built for the project.
This project has not only expanded our knowledge of earth as a building material, but let us explore what can be achieved with grit, collaboration and positivity. It has been a learning experience which has expanded our perspectives on perfection and the worth in innovating without the often restrictive fear of failure.