Tuesday, December 12, 2017

Prefabrication experiments - 149 - Future visions - 10 - Building Foundations

Earthworks and building foundations symbolically and physically anchor buildings to their location. Whether buildings seem to grow from their context or float over their sites, local ground conditions and bearing capacity dictate the manner in which a building’s vertical loads are transmitted to some type of footing. Akin to the manner in which a snowshoe spreads a person’s weight onto a larger surface area, building foundations and footings distribute loads onto a larger footprint. Foundations require soil that is stable enough to support loads and that it remains so, in order to keep the building standing throughout its life. 

Traditionally concrete, stone or in some cases carbonized or treated timber, were used to affix a building into position. Rot resistant materials such as concrete and stone are more commonly employed as foundations are susceptible to water infiltration, frost heaving, or soil instability. Recently, insulated concrete formwork is integrating conventional construction as the formwork reduces waste while increasing the wall’s thermal performance.

As ecosystems become increasingly fragile, researchers are developing innovative ways to improve foundation strategies. Rising flood plains, melting permafrost, sinking water tables are just some of the issues pressuring traditional monolithic foundations. A research group lead by architect Dr. Martyn Dade-Robertson from Newcastle University is proposing a type of bacteria to reinforce soil weaknesses by creating a type of bio-concrete, which could respond to changing conditions over time adjusting support structures as needed. 


Before integrating this type of self-adapting soil becomes common, lightweight, multipoint, space frame and modular structures are also being used in fragile conditions to reform standard concrete foundations and footings.  Platforms are built from triangulated structures onto which buildings are attached as a structure to a large raft. Triodetic structures, a Canadian firm well known for their space frame assemblies, has begun marketing and employing this type of raft foundation for a diversity of applications. Space frame foundations can be tailored to different sites. Buildings can sit lightly on fragile soils reducing local soil disturbance. Assembled from steel tubes and connectors, this type of foundation could conceivably be adjusted to changing conditions over time. Further this type of dry assembly of prefabricated components allows the structure to be dismounted and redeployed in other conditions.

Multi-Point foundation system by Triodetic