For my final project, I plan on using photogrammetry to expand on my Typology project of Pittsburgh’s bridges
My goal is to create a collection of bridge captures that highlights our aging infrastructure, and the beauty present within it. My intention is to show the beauty of the bridges when taken out of context, and to show the different types of erosion that can affect them.
Background
I came up with the idea for this project in September after reading this article about the state of steel bridges in the US. They found that over 25 percent of all bridges in the US will collapse by 2050, due to the extreme temperature fluctuation throughout the planet as a result of climate change. I immediately connected this to Pittsburgh, and the Fern Hollow bridge collapse. There are almost 450 bridges within Pittsburgh city limits (446 to be exact) and I found this report from June 2024 that concluded that 15 percent of these bridges are in poor condition and at risk of failure right now.
As my project developed, I began to realize how beautiful the undersides of bridges actually are. My interest became less about their safety, and more about their beauty, especially because the undersides of the bridges are usually only understood for their utility and not their aesthetics. We often pay attention to bridges while driving across them, or seeing them from a distance, but we don’t notice them as much while driving under them, and the undersides of bridges are often just as beautiful as the top. These parts of the bridges are almost always designed to prioritize safety and functionality over beauty, but they are often incredibly beautiful anyways.
Method
I plan to use photogrammetry and Agisoft to create my 3d models. In the past I used Polycam, so I hope to expand my project and the detail within the bridges by using a more professional camera and better software. My original scans were pretty crunchy, and at times the detail didn’t translate properly, so I’m hoping that using a better camera and professional software will lead to better results. That being said, I’m more interested in volume than perfection, so I will most likely prioritize having more scans over having a couple really great ones/perfecting my process. I think the bridges are most powerful when placed in relation to each other, rather than isolated, so I want as many as I can.
My biggest concern right now is that I’m not going to do it correctly! It is actually incredibly challenging to do Photogrammetry for something so large. It’s hard to standardize camera angles, lighting, and takes an extraordinary amount of time to do correctly, and not many people have made tutorials for capturing something at this size. In my first iteration, I only had about a 65% success rate, which is difficult when each bridge takes so much of my time, and if I do one incorrectly, that’s an hour or more of work left unusable. This was the biggest benefit of Polycam, as I could find out in realtime if a capture had failed and potentially fix it before moving on. I’m hoping that now that I’m more familiar with photogrammetry, I should be able to get better results, but I’m worried about the inconsistent lighting conditions that come with being outside, and the reflective nature of metal in daylight. I’m trying to remain flexible, and I think it’s possible Polycam will actually be my best option, but it’s worth trying with more professional software. I am also thinking about using polycam to take the captures, but then processing them through Agisoft.
Additional Resources:
More about bridge diagnosis methods