The Video

Its a short one this week, and the end is rather abrupt, but here it is anyway…

 

Why a Quonset hut?

My house design is an experiment with a variety of different arch forms.  Since it is a self build, I kept most of my spans shorter than 15 ft.  The exception is the garage.  I wanted a 3 car garage for practical purposes and decided to use a Quonset hut to form the wider span.

The quonset hut could probably support a significant earth load, if it were carefully distributed, etc. But in my design, it is really just fancy formwork to hold up the rebar and shotcrete that will actually support the earth.

My build also required a workshop to build the other components, and the Quonset hut is something that could be erected quickly, early in the construction, and provide that place.  I have used it to weld steel arches, store materials, and most importantly, to form my large concrete ribs.

Why build it in two stages?

The rib forms needed to be built on a large flat surface, out of the weather.   But we would also need to use a crane to move them to where they needed to go.  The ribs weigh 5000 lbs each, so I couldn’t roll them out across the gravel or dirt.  Instead, I needed to keep them on the slab, but also needed open sky above them for the crane.

The solution was to build only 2/3rds of the Quonset hut on the slab floor.  I could use that sheltered space at the back to form the ribs.  I would then jack them up and pull them forward to the open 3rd where a crane could lift them up and over to where they needed to go.

 

When the crane came out, it did lift them straight up and over, but I noticed that it actually had a telescoping arm.  I asked the operator and he said that he could lift them up and pull them out of the building if I finished it…

The ribs were taking me a long time to make and closing off the building would save me a lot of hassle, so that seemed like a good idea.  It had been almost a year since the first 2/3rds were erected.

The final 3rd

My parents came down to visit and to pick up their camper. Anyway, it was windy and we didn’t want to try erecting Quonset sections with just the three of us. However, that is a good number for assembling the steel arches, so we spent most of the afternoon doing that.

 

The following week, I put out help requests on Facebook and at work. The first few days, I was worried that I wouldn’t have at least 4 people there at one single time.  By the end of the week there were lots of people volunteering and I was buying a few extra half inch sockets and wrenches so there would be tools for everyone.  One co-worker even volunteered his whole family of very capable teens.

 

The steel ribs went up very quickly.  7 in under two hours.  We were actually done before the Pizza lunch I ordered arrived.  No worries, we had other work to do (not captured on film).

Mistakes

Because these new steel arch sections were were bolted to the rest of the Quonset hut, which was already bolted and concreted to the slab, and because they were very heavy, I wasn’t too worried about the new section blowing away. With 13 people working in parallel to bolt the sections together, I didn’t want to interrupt that flow and make everyone stand around while I drilled and bolted the steel sections down.  I figured I would come back and take care of the anchor bolts next time…

However, by the next time I went out there, I found that the wind had lifted the front third of the Quonset out of the groove.  We ended up wasting several man hours and a lot of sweat getting it back into place.

 

I should have known better because this is a pretty typical fluid dynamics problem that I had to do several times at school.

Another “mistake” that I pretty much accepted was that my building was a little longer than it should have been and ended up hanging over the edge by a few inches.  I ended up cutting that off so it wouldn’t get in the way of the end wall, but that is another story.