The Bridge That Can Withstand Anything (under 13lbs) !!!

Hello and welcome to my blog. The subject of this blog post is based on the class I have been taking for the last couple of weeks called Urban Planning. In this STEAM focused course, we have been studying the laws of physics and how they apply to the structures around us that are utilized every day. We began this unit, Load, by looking into Issac Newton's three laws of motion. We also got deeper into some trigonometry and in combination with our knowledge of physics, looked at some foundational structures used all around the world, bridges! My class took a short walk to the Chicago Riverwalk to investigate the well-known Chicago bridges. Looking at these structures in real time helped contextualize the things we had been learning in the classroom and get a better sense of how to move forward in my own project. Which brings us to my first unit Action Project. For this action project, I partnered up with one of my classmates, DC, who I’ve worked with in the past. Together, we created a model version of a hypothetical plan for an existing bridge in Chicago called the I-90 overpass. We got inspiration from an existing bridge in Chicago, located at north Wells st., crossing over the Chicago River. The rest of this blog post will showcase the process and finalized version of our completed project.

In the beginning process of creating our bridge design, my partner and I began sketching out some ideas. While my original idea was a bit more creatively reaching, with a spiraling base and neon lights lining the sides, my partner went for more simplicity and efficiency of resources. We decided to go with a design that was closer to my partner’s idea. This bridge ended up being similar to those currently in Chicago with trusses on both sides and two levels, the first for cars and other automobiles, and the second for bikers. While he was adding further details to his sketch, I decided to actually lay out the 50 popsicle sticks we were given, as our only resource besides glue, to see how our design would play out and if there were adjustments that needed to be made. Once we had a better idea of what exactly we wanted, we started gluing. 

In the process of creating our bridge, my class had a guest structural engineer come speak to us about his job and give feedback on some of our bridges. He gave some helpful advice on my partner and my bridge. He suggested some ideas on adding additional support. 

Here, you can see the image of our original sketches.

 

 

Here is an image of our finalized bridge model.

 

Above, is our inspiration bridge.

Above, shows the bearing points of the bridge along with the top and bottom chords.

 

Above, shows the compression and tension acting on the bridge. 

Our bridge was able to hold about 13 pounds before breaking.

Here, we can see the law of sine and the law of cosine at play within our structure.

Energy:


Potential -

mass x gravity x height

5.8kg x 9.8m/s/s x 0.889m = 503.7 J


Velocity -

9.8m/s/s downward


Kinetic -

½ (mass)(velocity)^2

½ (5.8kg)(9.8m/s)^2

(2.9)(96.04) = J


The law of conservation of energy tells us that energy cannot be created nor destroyed, it merely changes form. In this situation, we can see that it takes more energy for the bridge to stay in place than to be actively falling.

Sustainable development goal 11, sustainable cities and communities, aims to “make cities and human settlements inclusive, safe, resilient, and sustainable.” This goal addresses the current issues with communities regarding their infrastructure deterioration, affordability, and access to basic needs. The design of the bridge we created focused on resilience and safety. 

 I was proud of what I was able to create with my partner. I think being able to combine our skills was helpful in creating this project. I to begin this class with this action project was helpful because now I'm looking forward to what else this class has to offer.