Beam Design

[Eric Dunn]

Still struggling to understand the concepts and get the software working, but investigating is bring up some questions.

What level of structural design has gone into the support structures used in the wikihouse design? Seems to me there is just far too much wood being used.

Comparing 2x4 wall construction and standard manufactured wood beams with the wikihouse and it really seems like too much.

A 9.5 inch deep plywood beam with a single plywood web and 1.25 inch lumber top and bottom can span 15 feet unsupported with beams on 16 in centers.

Or perhaps I'm getting stuck on details and missing the advantages (beside being able to play with CNC routers).

[Eric Dunn]

And why only S-joints?

No mortice and tenon joints? No roof joist overhangs?

Eliminating all the angled transition parts would seriously reduce the material waste by making nesting of parts easier. And would make roof overhangs easy to build into the structures.

Woodworking and wood frame construction is hundreds (thousands?) of years old. I'm struggling to see evidence of any old techniques being respected or modified to incorporate new materials and methods.

[Paul Pangrazzi]

Hello Eric,

You're asking great questions, and I hope for similarly interested parties... we'll get some answers (or at least healthy discussion around the ideas involved.) I find wikihouse fascinating as a concept. In reality, it's been difficult for me to get involved due to the high barrier for entry (personally.)

I considered getting the shapeoko cnc kit just to start creating models, but even that seemed a high price to pay for testing concepts... and I have secretly been waiting for someone, anyone, to jump in with unlimited time and resources to show us all how it can be done. :)

I suppose I'm being unrealistic and need to contribute, which is exactly the nature of this open sourced model. Still, I'm not convinced *enough* to put any money/time into it quite yet.

【ツ】paul

[nick]

Frame and panel construction is a pretty solid and time tested method for building.  Sometimes I feel that most of us here are bound by the standards and codes of first world building practices. The ironic part is that this concept would be most beneficial, needed and excel in the developing world.  Granted, when you make direct comparison to the modern components of "stick Frame" construction, the list of perceived differences and discrepancies will begin and run for miles. Believe me, I have asked those same questions and drawn similar conclusions many many times over.  I started working on my project in 2009 and worked on it primarily in 2011 and 2012.In those few years, my work was very closely tied to AEC and I was able to pursue a lot of R&D. During that time I found the Wikihouse. Since then, the focus of the work coming into our CNC shop has shifted.
     There are infinite debates to be had regarding overhangs, weight distrubution, DP ratings, seismic loads, foundations, multiple stories etc.  What I have found personally through seeking out structural engineers, building code officers and such is almost the same thing every time. " Well I don't have a table or static chart for reference data to compare it to."  I had never really used Sketchup until I really got involved with the project. Most of my data was originated in other CAD software. I did try to shift most of the information over and in that time. Sketchup was updated and ultimately became another companies asset.  I had problems with the Ruby plugin, so I bought a book on Ruby script to teach myself. It has been a long, slow road for me with that one.  To address the structural issues, I started designing parts in SolidWorks to use the Von Mises ductile failure criteria for testing the isolated parts.  Once again, very steep learning curve. 

    There are a lot of geographical factors that are in play here as well.  The conventional home design follows a rectilinear pattern. Which is easy to build and relatively stable but also very weak in certain situations. The platform here lends itself to having more freedom to design a suitable structure based on the particular needs of people and their regions.  For example, people living in a very rainy, environment may want to clad the exterior of their wikihouse with a continual impervious membrane. 

  I too feel like this is still a very design heavy concept and the necessary real world application and testing needs to catch up. I also believe that the designs represented are totally adequate for their intended purpose and it is hard to make a direct comparison to the conventional. 

Someone here once mentioned a more basic and affordable way to test the concepts with the suggestion of making a Wikibeehive or doghouse. A few months later, someone did show up with a Wikibeehive.  The Wikished seems to be a logical step in working through some concepts as well.  Personally, I am leaning more to the SIP approach.  Being able to have interior and exterior cladding, insulation, mechanical and structural support.  It too has its own limitations but there are so many upsides that can be taken advantage of with the CNC and digital fabrication as well as transportability and ease of assembly.

At this time I have exhausted my own personal resources to put into the cause and without some sort of endowment or University to fund me, I am on pause. Hopefully not for too long!

[*-*]

I'll agree that starting with useable and functional sheds (or demonstration emergency shelter) certainly seems to be a logical step.

As for: " Well I don't have a table or static chart for reference data to compare it to."

Well, it falls upon the people proposing new construction methods to standardize their methods and test the components so that those comparisons can be made.

Seeing as there are industry associations for the wood industry, perhaps one of those would be a required partner to move the idea forward with materials and testing.

Was by the local hardware big box store and you can buy plywood and pre-built shed frames. IMO, a wikihouse challenge should be to match the cost and ease of assembly of those parts.

[nick]

The process appears to be heading in that direction in a general sense.  WISA ply for example.

Hitting a certain price point of a mass produced kit shed is a great goal. 

There are test facilities that will certify the structural and safety ratings of the engineered parts and buildings as a whole unit.  Wind tunnels and seismic shake tables etc. and they require copious amounts of funding. Which, as you said, partnering with a manufacturer could possibly help ease that financial burden. Or an engineering school like MIT has done with their digitally fabricated house.  I have tried my hand at reaching out to an engineered wood manufacturer and they appeared to like the idea and of using their product especially. 

[Alex Whitcroft]

Yes.  Been thinking about this.  A partnership agreement with manufacturers would be really useful.  Eg:

- Discounted materials for WikiHouse projects

- Them helping to fund testing / certification approvals, etc

It may even work for other materials beyond the wood.  Systems, cladding, finishes, etc... they get associated with WikiHouse projects and more business and WikiHouse gets cheaper materials.