A2 - Lester

The truss was made with interconnecting right triangles in a rectangular shape that comes to points at either end. Triangles are the strongest structures and can bear the most weight in a stress test, as opposed to rectangles which could morph and bend. Pieces include blue (2.215”) and yellow (3.375”) K’nex chords, as well as 180 degree gusset plates and 360 degree gusset plates to serve as connectors. The top has only 180 degree gusset pieces to keep a flat surface for the testing board to be placed. The two sides of the bridge are connected by yellow (3.375”) pieces that are securely fastened in the unused snaps of the 180 degree gusset plates. The images show the basic structure of the design, but do not show the connecting gusset plates due to their complex shapes. The length of the bridge is estimated at this point since the connecting gussets are not taken into account. They are not essential to illustrating this first-draft model, although they are essential in cost calculations. Future models will show the connecting gusset plates and incorporate the exact dimensions of the K’nex chords and gussets.

My bridge did not change much during the design. I began with the intentions of using right triangles, since K’nex pieces are made with the intention that each piece completes a right triangle with the next largest size. This knowledge helped me choose the pieces I wanted to use; the blue and yellow chords fit perfectly with my design intentions. The only aspect that changed was the type of connecting gussets being used. At first, I used the 360 degree gussets for all connections. Later in the design process I realized that a flat top bed would be needed, so I switched to the 180 degree gusset connectors.

During this process, I realized that K’nex pieces are made with precise dimension that perfectly connect with each other in successive right triangles. I worked with the Autocad – Architectural Desktop program for the first time in a few months and was able to refresh my memory of the features it has available. I practiced creating a design that was both functional and cost efficient, something that will be essential in future academic and real-world problems. 

-Belinda Lester