What building technique should we use?

For a while now, I have been researching ways to build economic, earthquake-resistant classrooms for the school. I am already feeling frustrated and want to prevail upon the mentors for guidance. Please read the following to share you insights.  

We can build the school using one of the following techniques:

1. Reinforced cement concrete (RCC) column and beam
2. Stone
3. Confined masonry along with autoclaved aerated concrete (AAC) blocks
4. Compressed stabilized earth (CSE) blocks

Let’s go over each method.

RCC based classrooms: It involves building RCC columns, beams and slabs first followed by brick or AAC block masonry. This is most popular way of building nowadays.

It is the most expensive, about Rs. 1600 per square foot of cost in the hills where the construction material is hauled up from the plains at a cost of about Rs. 80 to 100 per quintal. Earthquake resistance depends on the quality of construction as well as the quality of the materials used.

Stone based classrooms: Locally sourced stone costs about Rs. 11000 a dumper which carries about 4 to 5 cubic meters of stone. A classroom will require at least 120 cubic meters of stone. Stone has an almost infinite life. It provides great insulation against the elements keeping both cold and hot out and provides a majestic appearance.

However, further research revealed that stone buildings may not fare that well against earthquakes and will require reinforcements using RCC beams and bonds, rebar, and galvanized meshes in addition to using good masonry techniques.

Here are a few links:

1. Improving the Seismic Performance of Stone Masonry Buildings (will open a pdf)

2. A Tutorial on Improving the SeismicPerformance of Stone Masonry Dwellings:A Compendium of Worldwide Experiences (will open a pdf)

3. Technical Guidelines & Information for Stone Construction In Uttarakhand (will open a pdf)

 

Confined masonry techniques using AAC blocks: Confined masonry costs about 30% less than traditional RCC building techniques. This is my second most preferred method. Although it does entail hauling up a lot of material from the plains which again drives up the costs. 

 Compressed stabilized earth blocks: This is my most preferred method. Compressed stabilized earth blocks or CSE blocks are made using the techniques elicited by the Auroville Earth Institute, Pondicherry. It requires training in Auroville (costs about Rs. 60000 including online classes and a month long stay at Auroville) and buying a machine (Auram 3000) for building the blocks. The machine costs about 500,000 to 1100,000 depending upon the number and types of moulds one buys. This machine can make about 700 to 800 bricks a day. A classroom requires approximately 10000. The interlocking of bricks with rebar placed as reinforcement through the holes in the bricks makes the wall strong, straight or smooth, requiring very little plaster work. It also provides employment to about 7 to 10 locals. A single brick will cost about Rs. 13 to make.

But a classroom made using interlocking bricks will only cost 3 to 4 lakhs. Please check the following videos related to CSEBs. Once we have the machine, we can build classrooms inexpensively using mostly local materials and labour. Thus driving down development costs substantially.

 

Here are a few videos.

https://www.youtube.com/watch?v=98tOy2VJ74Q

 

https://www.youtube.com/watch?v=OQBWab9q5Zs

 

https://www.youtube.com/watch?v=53vCExJ4HqI

 

https://www.youtube.com/watch?v=9BHDzXTlk8M