Inno-native materials part 2

One unfortunate truth about the construction scene in developing countries is that a lot of the construction is technically supervised by construction managers. Technically, a construction manager is not a structural engineer so they shouldn't sign off on structures. But in an unregulated region, they do.

As a result, the building scene is not designed with a thorough look at the ability of the structure to withstand loads from earthquakes, heat, floods and impacts. There is even less regard for considerations about the choice of materials for design that will be sustainable economically in the long term.

In tropical regions the structural challenges that buildings face include flooding(erosion of materials in long rainy seasons), strong winds, lightning and thunder in addition to the normal design loads from possible earthquakes, foundation collapse, dynamic loads  and gravitational loads).In addition to structural challenges the construction industry needs a sustainable local industry that supplies affordable materials for residential and commercial construction.

I am personally drawn to designing with light materials and simple family homes. Light materials that I like include laminated bamboo,timber and metals(steel, etc). I prefer simply framed buildings with as little concrete as possible for tropical areas. The challenge for a structural engineer such as me is that it is important, in designing with lightweight materials, that the buildings can withstand shocks in the form of flooding, earthquakes and strong winds.

One light local material that I'd like to explore is adobe blocks. Adobe is a natural building material made from sand, clay, and water, with some kind of fibrous or organic material (sticks, straw, dung), which is shaped into bricks using frames and dried in the sun. Adobe's advantages include its availability, affordability, local technical knowledge and it's strength when prepared properly. Adobe's fatal weakness is that it is prone to massive damage and destruction in the event of an earthquake. It is also susceptible to erosion, insect infestation and pure attrition.

There is now a strong body of research on how to manufacture adobe bricks for structural design. A serious construction industry would do well to adopt this body of knowledge into building codes to ensure that adoption of adobe bricks doesn't leave a community prone to seismic and flood damage. In earthquake prone regions such parts of Southeastern Ghana(where Accra the capital is located), ultimately, it will take sound seismic foundation design to protect homes because a reliance on the superstructure of a building is inadequate. More importantly, after an earthquake affects the superstructure of a building, it becomes inhabitable even if it does not collapse and cause fatal damage.

Ultimately the use of inno-native structural materials should not preclude the use of other less 'desirable' materials such as concrete and imported or expensive metals. Instead they should augment them.