Technology Engineering and Design: Balsa Bridge

The goal of this class project was to design and construct a balsa wood bridge that could hold as much weight (in lbs. of books) as possible. Criteria included: the bridge had to be identical on both sides, it had to be between 10.5-11.5 inches in width, be atleast 2 inches in height, and have a minimum of 2 inches in width. While Constraints included: 3 balsa sticks per side, 2 balsa sticks in the middle, and no metal pins or fasteners to help strengthen the bridge.

West Point Bridge Simulator

Before I began any virtual or physical modeling, I used the West Point Bridge Simulator to confirm research I did about which bridge structures were the strongest against factors such as torsion, bending or the load on the bridge.

Refined Sketch

My next step was to create a refined sketch for my Truss bridge design that I would then use to create a SolidWorks model.

SolidWorks Stress Analysis

In order to gauge how many pounds of books my Truss birdge could hold until breaking, I ran a Stress Analysis Test in SolidWorks.

SolidWorks 3D Model

Here is an isometric view of my virtual 3D model with the balsa wood material selected.

Template for Construction

Once I was ready to build my prototype, I did so by converting my 3D model into a drawing file to use as a "to scale" template for construction.

Testing the Prototype

After physical testing, my bridge held 17 pounds of books before breaking.