We’ve completed levels 8 and 9 …
… on level 9 we were joined by Itsik and Yifat who visited with us for a week … so we reached and celebrated the end of 9 together.
In level 9 we also put in additional vertical reinforcement by pounding in rebars into the longest stretch of buried wall that we have (~6 meters) … and we will continue to do that in an interlaced pattern to give the wall some more strength to resist the weight of the earth piling up behind it.
Which brings us to today … soil … we called the excavator back (marking what is probably the half-way point of wall construction) … to start backfilling and bringing some more soil to our mixing station (so that I don’t need to carry it in a wheelbarrow). Yesterday we prepared by pulling the plastic covering over the walls
.. and so it started … and very quickly the corner behind the first retaining wall was filled up ….
… during the backfilling, a new soil pile near the mixing station started to appear
… and before you know it (almost three hours later) the backfilling was complete …. so from the outside we are back at ground level (which does make some maneuvering on the walls easier)
… and a huge pile of soil (30+ cubic meters) is now blocking the entrance and hiding the site … when that soil is gone, construction of the walls should be complete (or very close to completion)
As the work progressed we realized we were going through A LOT (= surprising amount) of soil … we’ve used up most of the free soil on and around the site … and it doesn’t look like what we have left will be enogh to complete backfilling and covering the structure. At first this felt like a potential problem … but it quickly transformed into opportunity. It looks like the supply of soil needed to complete this project will overlap and lead into the next project. One option weve been discussing is a small lake (a whole other story). Another option is to start excavating what may be the next construction project … either way … it left us with a pleasant sense of continuity 🙂
Before presenting some highlights I would add that there are a few details which, to my understanding are only correct in the context of typical above ground houses, less so with bermed or underground structures.
“At present, there are over 15,000 Earthbag buildings worldwide with recent Earthbag constructions gaining approval under strict US building codes.
An estimated 55 Earthbag structures built in Nepal survived the 2015 earthquake, in regions ranging from Solokumbu to Sindhupalchok to Kathmandu.
… The main material of an Earthbag structure is ordinary soil obtainable at the worksite.
… A study by the U.S. Federal Highway Administration found that the half -life of polypropylene fabrics in benign environments can be 500 years or more. The
bags themselves have a tensile strength even higher than that of steel, and can resist circumferential forces generated from the weight above.
… An Earthbag building uses its own weight to anchor itself to the rubble trench foundation. Since the superstructure is not attached to the foundation by bolts or rebars, the foundation and the
superstructure are able to move independently minimizing the shock transfer to the walls. A rubble trench is also built of individual units rather than a continuous beam further absorbing the shock.
Earthbags are resilient. As per an experimental study on vibration reduction … Earthbags have a relatively high damping ratio with horizontal as well as well as vertical vibrations effectively reduced.
… All of these components make Earthbag structures extremely earthquake-resistant. Tests done in accordance with IBC standards have found that Earthbag construction far exceeds Zone 4 standards, devised to protect against the very highest level of seismic activity. Numerous Earthbag structures have been built in the United States. Earthbag structures are permitted by the California Building Code, the toughest in the United States due to high seismic activity.”
After finishing level 6 we ordered another batch of sand (another 6 cubic meters, like the first batch).
… and it was delivered just as we were getting started on Level 7 (because of tricky vehicle access to our property it came in two batches of 3 cubic meters) … this is the second batch being delivered with the first one in place:
Layer 7 was relatively smooth sailing … that is with uninterrupted and continuous bag laying … also the overall wall length is shortening as both of the retaining walls are starting to shorten:
This weekend I was alone and so could not progress with construction so I focused on preparing soil for the next two layers (I hope):
We’ve pretty much used up the entire side-hill that was created during excavation. I pulled down 45 roughly sifted wheelbarrows of soil. You can see the soil pile that I’ve prepared behind the sand pile. That should allow us to make good progress with mixing and packing the next two layers. Its a tough job … and I hope I’ve seen the end of it .. at least for a while. After the next two layers we want to bring in the excavator to do some backfilling and to collect a large pile of soil next to the sand-pile … that should take us nearly to the end of the earthbag phase of this project
We’ve had a fairly long stretch of work without rain interruption … but that is about to change. I’ve pulled the plastic that will cover the walls, over the walls … and later today will go out and layout more tarps to keep the site as dry as possible.
Level 5 was already finished yesterday … but today required a bit more preparations before starting level 6.
The central preparation was putting in the plastic moisture barrier around the entire external perimeter of the wall. We spread it out, folded the corner down and covered it with soil to hold it in place … while doing that we also starting a bit more backfilling to cover the earth-tubes. Thebackfilling gave me a sense that the structure is physicall connecting with the place. Also we got a taste of wha tbackfilling would be like … and we look forward to bringing the excavator back 🙂
Level 5 is also where we put in the 3 velcros to which we will attach electric sockets:
Some pictures of level 5 … with a glimpse of Rodica, a first volunteer to visit Bhudeva.
… and all preparations done and ready to go with level 6 … Vasile mounted on Maria with a tube ready to be filled:
With the second layer finished we needed to position the inner ends of the ventillation tubes … we had to assemble the corner joints and the parts that oenetrate the wall used cob to continue the slight angle that was already established with the long section of the pipe.
The days are getting noticeable shorter, and we felt we wanted to be work longer at the tail end of our evening work sessions … so … lights:
After finishing the third level (we are already more than half finished with the 4th) we did some simple level testing and got very good results:
We are now settling into a continuous flow of work moving endless wheelbarrows of soil … things are moving a bit slower because we are now two people … things to look forward to: wrapping the structure with a moisture barrier, backfilling, electrical installation working higher up, earthbag arches … stay tuned.