RAMMED EARTH AND STEEL (Reinforcement Bars)

In exploring the structural possibilities within Rammed Earth external walls, the use of steel reinforcement had become an important avenue in which to pursue. Although this would not be the fundamental structural basis upon which these external walls would depend on - in reference to the weight of the roof and the structure that would have to be applied to sustain such an element - this would be an interesting topic in which to begin to understand. 

The use of steel reinforcement bars, or 'Rebars', is a practice used largely within concrete forms and structures, regarded as 'formwork' in allowing shapes to be created and then coated in a cast Insitu concrete substance. 

Similarly, this process can be used within Rammed Earth construction, although there are significant restrictions in terms of the shapes, spans and structures that can be created from this process. The image above outlines most clearly, how in actual fact these rebars are used within an external, Rammed Earth wall. Used as a formwork of sorts, the moist earth would then coat this skeleton, filled between two ply or steel casing sheets and then literally rammed and compacted together as to create a solid wall coating. This internal, skeletal reinforcement allows for less movement within the walls, as well as complementing the compact nature of the structure as a whole. 

These technique can be seen applied to the structure presented within the sectional technical image (left), as a geometric pattern within the walls overall build up. These reinforcement bars, resemble a mesh inside of the earth, tied together to create a grid like sheet formwork for materials to be cast onto. As mentioned before, this is most popular as a process within cast insitu concrete construction and as a result of the material properties of both concrete and rammed earth, would both take significant periods of time to construct. This would be a result of the duration of drying periods.

This form work, in terms of the rebars that are used within Rammed Earth walls and structures, also provide a degree of earthquake protection or support, perhaps evident by the abundance of these structures within earthquake prone countries or continents. 

The image to the right presents the process of constructing a solid Rammed Earth wall most clearly, in presenting the formwork that is required to pour the moist earth between, as well as the vertical steel reinforcement that would have horizontal elements then tied to them before the next formwork and pouring is to commence. These are the steel bars that stretch high above the construction workers, pictured, which are most likely mapping the height of the structure that would be applied to this skeletal frame.