A2: Breslin

     The aim of this project was to build a bridge using different Knex pieces. Each piece had a different length and price tag. The goal was to construct a bridge that I believed would be durable and strong as well as low in cost. When designing the bridge I had come up with many different ideas but none that I thought would be constructed with a lower price tag. I had decided to keep the design simple and stick to basic concepts. Below is the design of the bridge I have created.

Bridge Design

Red lines represent 5" long chord
Yellow lines represent 3-3/8" long chord
Purple dots represent 180 degree grooved gusset plates

     Side View of Bridge Design:

     Top View of Bridge Design:

      Throughout the design process, my bridge design had not changed drastically. I knew from the start that I would like the bridge to take on the shape of a trapezoid from the side view. This aspect of the design remained constant throughout. Then next thing I decided was to add a series of right triangles into the side of the bridge. After completing the sides I determined that I would like to carry on the same idea to the top and bottom of the bridge as well. Over all I has used thirty-four 3-3/8” long chords, fourteen 5” long chords and forty-eight 180 degree grooved gusset plates. The price of the bridge design would cost a total of $175,000. Below is the Truss Bill of Materials which indicated the cost of each piece used and the total cost of the bridge.

     Truss Bill of Materials:

      After completing the design of the bridge I had learned many things. Developing an idea for a bridge takes a lot of time and effort. It is important to stick to simple realistic concepts and only get fancy if it is needed. Also building the strongest and safest bridge possible does not make it the most efficient. A bridge must have as much sustainability as possible with the lowest overall cost.