Bamboo’s Not Just For Pandas

 

Courtesy of Mr. Lucas Bergstrom

So while a panda would have endeavored to eat all that bamboo, I happened to find an alternative use for it with the help of my two classmates.  Let me take a step backwards to explain just how I ended up making a bamboo truss as opposed to several thousand chopsticks.  (Although at times, that felt like a very, very, viable option.)

So I’m at the green dot and Roatan, Honduras is at the reddish dot.  There’s A LOT of distance between us, and Google maps keeps refusing to give me driving directions there.  Perhaps because Roatan is an island located off of the mainland of Honduras.  Now how exactly does someone firmly rooted in the Midwest, amidst a sea of grass, find themselves working on an island project several thousand miles south?

The abridged version of the story goes something like this.  I started my fifth year of architecture and selected a studio that would be focusing on two projects.  The first project would be located in Kansas City and the second would take place in Roatan, Honduras.  Midway through the fall semester, after having worked on the Kansas City project, I switched gears and began working on what was to be a Marine Reef Research Center.  In order to really kick off the project I planned on traveling down to Honduras for a week with three of my classmates and one of my professors.  Through some unforeseen passport issues (a year earlier my passport had been stolen in Sierra Leone) I wasn’t allowed to board the plane.  Honduras requires that your passport is valid for 3 months beyond your date of departure and mine missed that deadline by three days.  But all was not lost!  My classmates returned with plenty of photos, information, interviews and solid material to start the research and design of the project.

One of the most notable realizations that my classmates and I came across was the fact that the indigenous people emulated the architecture of the more wealthy occupants of Roatan.  This was embodied in their construction of CMU brick houses.  The problem in a tropical climate with a CMU brick house is that you’ve in essence created yourself a wonderful little oven to bake in.  If you’ve ever been to a tropical area, the last thing you want is more heat!  And unfortunately due to the thermal mass of the CMU, it would re-radiate all it’s stored heat from the sun onto the occupants during the night.  This meant that their homes were almost always WARMER than the temperature outside! So the lesson I took from this experience was that I needed to create a type of architecture that could be easily replicated by the people that would in fact function in a manner that would improve their quality of their life.  Interestingly enough, this is the exact same thing that I saw occurring on the other side of the Atlantic Ocean over in Sierra Leone!

Now along comes the problem of getting rid of the CMU block.  The construction of a CMU building isn’t too difficult so I knew that my idea needed to be just as easy.  Since CMU acts as the structure and facade of the house I believed that I needed to concentrate on finding some kind of structure that could be an alternative and then look into possible alternatives for cladding.  I also wanted to ensure that whatever the selection was, that it would be sustainable, wouldn’t require material to be imported, could help stimulate the local trades, and wasn’t so high tech that it would require a master’s degree in engineering to assemble.  After looking and looking, I finally found some hope in none other than bamboo scaffolding.  People were successfully piling bamboo scaffolding several stories high by lashing it together and it was performing tremendously!  It rivaled concrete in compression, has a higher tensile strength than many steel alloys, and in a tropical environment can grow up to a meter in a day!  In many places it is considered an evasive weed.  But to me, I looked at it fondly as being a potential solution to a problem.

Roatan is an island and the main way to travel is out on the water in a boat.  Usually the boat is made from fiberglass.  So the people of Roatan know how to work with fiberglass and readily have it on hand.  And I have bamboo that I need to form into a truss.  But I don’t want to bolt through it, or it may shear at the connection.  And I don’t want to embed it in concrete because I need it to remain light.  Metal connections could accommodate the circular profile of bamboo but they are expensive.  Once again looking at the scaffolding that is lashed together, it seemed that kind of thinking was in the right direction.  But instead of lashing the bamboo together with waxed cord or twine, what would happen if it was fiberglassed?  Fiberglass would adapt to any type of joint or connection no matter how oddly shaped it was.  It also possesses an incredible strength to weight ratio that would keep the truss nice and light.

My two colleagues, Mr. Campbell and Mr. Bergstrom, and I decided that even though we had no prior experience to fiberglassing, we would give it a shot and build two full scale bamboo trusses to see if this idea was possible.  So after ordering bamboo from San Diego I set about cutting the bamboo into the members we would need for the truss.  Since the bamboo came in 8′ lengths we decided to make this our truss length and after calculating expected loads, settled on a depth of 18 inches.  Using the CNC mill, we milled a jig out of rigid insulation that would hold the members in position as they were fiberglassed.  Photo montage!

We’ve already placed 600 lbs on the truss without any noticeable deflection and plan on going to 1200 lbs tomorrow.  If it successfully bears that weight, than it will will have carried twice the normal load which equates to a factor of safety of 2.  Which, all in all, isn’t too shabby for something pandas munch on and people consider a weed.

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