For this balsa wood bridge, I used a ‘K-Truss’ design with seven vertical members and 6 ‘K-Trusses’ per side. The K’s were the most challenging part of the build, because I had to calculate each ones length, and the approximate measure of the angle I had to cut into each one. All in all, the … Read more Classic ‘K-Truss’ Bridge Design (Balsa Wood)
This bridge is supporting 191lbs of weight. It didn’t break, that was all the weight we could fit in the trash can. I believe this is close to the maximum load it could hold because the platform the jig is resting on was significantly bowed. The rest of the structure was rock solid. The construction of the bridge is popsicle sticks
Here is a bridge using the K truss design made from Balsa wood. This bridges uses a combination of end and lap joints. You can see that where the slanted members of each K join together at the vertical member, there is an end joint. At the top and bottom chords, the joint is a … Read more Balsa Wood K Truss Bridge
The K Truss design was a variant from the Parker truss design. The Parker, in turn, came from the Pratt truss. The idea of the K truss is to break up the vertical members into smaller sections. This is because the vertical members are in compression. The shorter a member is, the more in can resist buckling from compression.