Saturday, December 18, 2010

Earthquake resistant houses

Most home builders in Manokwari city of West Papua must take into account earthquake resistant structures when constructing houses. The use of steel profiles or steel rods for pillars for multi-story buildings is highly recommended. Although metal buildings are strong and suitable for earthquake region, they are not fully popular due to aesthetics consideration. Home owners in Indonesia still prefer wooden framed houses with concrete walls as the most affordable and beautiful constructions.  The department of public works (called DPU or Departement Pekerjaan Umum) stipulate that all houses with two floors and above must have structural strength calculations done by architects and civil engineers who design the buildings when submitting their works to the department for obtaining their approval.
For small one floor homes, the use of hard wood for house frames is a common practice in this city. To hold the concrete walls, the construction workers hammer big nails along the wooden pillars and girders along the sides where the bricks of the concrete walls will be built. When earthquake hits the city, these nails will hold the walls from falling onto the ground and hit the occupants of the houses. The distance of the pillars has also been reduced to a maximum of 4 meters for family homes with two or three bedrooms.
Building materials for the foundation of the houses are granite stones or hard corals that are mined from the mountains. The mining of corals from the coastal area has been banned due to its destructive impact on the marine environment.
Although Papua is rich of timber, some home buyers in Manokwari still orders prefab building or wooden houses from Woloan village in North Sulawesi. These earthquake resistant wooden house of Minahasa, after being dismantled and shipped to Papua, will be reassembled and constructed on sites that have been cleared for them.
For Papua and Indonesian islands in general, wooden houses or concrete houses whose pillars are made of wood are the most recommended constructions. The use of wood is cheaper than steel frames. To prevent the wooden blocks and planks from deteriorating or decaying due to the changing weather, anti termite and base paints have to be applied on their surfaces. These kind of coatings will protect the wood for tens or even hundreds of years to come.
I used to study Archicad, a BIM modeling software for architects and home designers. This is a very powerful software for designing homes and big buildings. Although it has the ability of calculating the number of materials needed by the designed houses, it lacks features for strength calculation that is very important for houses that will be built in earthquake region such as Indonesia. Architects still need other software such as SAP 2000 to do the structural strength analysis. by Charles Roring
Also read:
Tropical wooden houses
Archicad and Home Design
Houses in earthquake zone
How to design roof with Archicad