CONSTRUCTING BUILDINGS IN SWAMPY GROUNDS.
Demand for land has led mankind to think outside the box in order to accommodate and build on top of wetlands.
Land around Runda, Kiambu road and Kasarani, near Thika Super Highway is prone to dotted marshlands.
The land value per acre, approximately kes 40m per acre, is quite high.
This means that the extra cost of expensive foundations that can support buildings on top of wet lands will be able to be returned from the rental/sale income of the building. If the land value was low, it would be more prudent to look for alternative land that will not necessitate an increase in foundation costs.
Using Pile foundations is a good way of constructing on march lands. Holes are drilled into the wet ground till solid rock, water drained out and a casing fitted inside to prevent water from entering into the hole.
Steel rebar is then put in place and finally, concrete poured inside. The exterior casing is then removed.
A concrete column is now in place to support the building. Most of the high-rise 20 floors and above buildings worldwide are supported through this method.
This method requires specialized mechanization and engineering expertise hence there will be a slight increase in the foundation construction costs compared to other normal foundation methods such as the common strip foundation method.
The returns on investment will be eventually realized since the cost of pile foundations is very minimal compared to the cost of land and rental/sale value of the complete building.
Francis Gichuhi kamau, Architect.