The Trailblazers
Overview
Jefferson County Open Space is home to over 54,000 acres of land and maintains over 230 miles of trail. The bridges throughout are sometimes destroyed by floods, fires, or other natural disasters. When this happens, it can take months to replace the bridge, as they need to be fabricated off-site and brought in by helicopter. Not only are bridges needed for trail access, but sometimes search and rescue crews need temporary access to a location where a bridge does not currently exist.
The proposed solution includes a backpackable and modular trail bridge that is made up of several small aluminum segments. Each segment is identical, and when fully assembled it utilizes a Howe Truss with dimensions of 4’ x 20’. Because the design comes in pieces, the size of the bridge is adjustable. Each segment is two feet long and constructed of square Aluminum 6063 tubing. A connector of smaller aluminum tubing is slid inside of the ends of each piece, which allows them to be bolted together. The bridge includes reinforces steel corners to allow for the support of hikers, bikers, and equestrians.
The bridge can be used for both short-term and long-term solutions, depending on the need. Different abutments and bolts have been analyzed in order to determine the optimal solution.
Live Zoom Chat
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Meeting ID: 976 6417 8949
Team Members
- Lian Doerr
- Ryan Hart
- JohnPaul Luke
- Thomas Mitchell
- Sophia Modar
- Brendan Nichols
- Hunter Szuszczewicz
The Client
- Jefferson County Open Space
Acknowledgements
Project Advisor: Dr. Kristoph Kinzli
Video
Elevator Pitch
Jefferson County Open Space is home to over 54,000 acres of land and maintains over 230 miles of trail. There are numerous bridges throughout this land, each built to a variety of different standards, and made from a variety of materials. The bridges throughout are sometimes destroyed by floods, fires, or other natural disasters. When this happens it can take months to replace the bridge. They need to be built in a facility offsite which requires a large workspace and the bridges need to be heli lifted in. Not only are bridges needed for trail access, but sometimes search and rescue crews need temporary access to a location where a bridge does not currently exist.
Design Approach
The team decided to pursue a beam truss bridge. There would have smaller sections that connect to make one the span of the bridge but would incorporate smaller trusses within instead of using “I” beams. This would mean that there will be different members in tension and compression rather than having the top purely in compression and the bottom purely in tension. Similar to the full-size truss bridge, this design utilized the Howe Truss.
This style of bridge will combine the advantages of the other bridge types and minimizes the disadvantages. The bridge will also have a good ratio of strength to amount of material as well as have a low center of mass. The assembly of this bridge onsite will be simple because the truss system in the beam can be welded offsite. This can be done well in advance so there is a stock in case of an emergency. This bridge can easily be modified to fit the desired length.
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Pros |
Cons |
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– Low on-site assembly time |
– Off-site welding |
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– Efficient use of materials |
– Complex pieces |
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– Low center of mass |
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– Easy modification of length |
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Design Solution
The proposed solution includes a bridge that is made up of several small aluminum segments. Each segment is identical, and when fully assembled it utilizes a Howe Truss. This was to simplify the manufacturing and assembly process, so that the bridge can be assembled quickly. Each segment is two feet long and constructed of square Aluminum 6063 tubing. The aluminum initially researched was a 6061 alloy, but a local vendor suggested 6063 due to shorter lead time and a lower likelihood of cracking during assembly.
A connector of smaller aluminum tubing is slid inside of the ends of each piece, which allows them to be bolted together. They are currently modeled as circular tubing due to the availability of materials but are subject to change. These pieces can be bolted together ahead of time in order to reduce the number of connections needed in the field. Two segments can also be attached, assuming four-foot segments can be transported.
Next Steps
Looking ahead, more testing will be completed to ensure that our design is to the highest quality. Things that we have considered in testing so far are: Axial and Bending Stress, Displacement, and Factor of Safety. We will continue to use these as the base calculations, as well as ensuring that the corners and connections are adequately reinforced.
The corner reinforcement also needs to be finalized. Initial testing demonstrated that the corners do not have a high enough factor of safety and the shear stress is too great with the full load. The abutments will also need to be designed, for both short-term and long-term solutions. Once the corners and connections are entirely designed, we will recreate the assembly in SolidWorks and run final testing.
Building codes also need to be analyzed since the design may be open to the public. Jefferson County has its own codes and regulations in place which need to be researched further so that the design does not violate any of them. Another thing that goes along with this is researching snow loads. The decking we chose has holes in it to allow for water to easily pass through it, but the bridge needs to still be analyzed with the largest loads anticipated as well as the largest snow loads to accommodate for absolute worst case. Once a full-sized bridge is assembled, it will need to be tested on flat ground by applying the maximum load in the center of the bridge. As discussed earlier, this will be the point with the greatest deflection, and it creates the largest amount of stress on the edges.
Meet the Team
JP Luke
My name is JohnPaul Luke or as I’m also called, JP. I am graduating this semester as Mechanical Engineering Major. I am from a small town in southern Indiana called Jasper. Throughout my time at Mines I have been lucky enough to volunteer with YoungLife as well as directly with Golden High School as a Tutor. I have also been a member of the Air Force ROTC program the past four and a half years. I am looking forward to my journey ahead in the Air Force and wherever it may take me. Outside of class I enjoy hiking, camping, skiing, and going to breweries with friends just like any other college student.
Lian Doerr
My name is Lian Doerr and I am a Senior in Mechanical Engineering. I am from Centennial, Colorado and love that I was able to stay local for college. In my free time I like to get outside and go hiking or play tennis. I also enjoy drawing and painting as well as cooking and baking. I am a CASA tutor for the school and love to help my peers succeed in their classes. I have found out that there are so many things that I can do with my degree, so I am still unsure exactly what my path forward will look like. My goal is to find work that I am very passionate about and stick with it for a long time. This project helped me explore what a more civil-sided project looks like. I am grateful for the opportunity to work together in a group and help come up with a unique solution to a problem that will help others.
Brendan Nichols
I am a senior in the mechanical engineering program at Colorado School of Mines. I am in the Air Force ROTC program at University of Colorado Boulder, and the Kappa Sigma Fraternity here at Mines. I enjoy fishing, dirt biking, and cooking for my friends.
Ryan Hart
My name is Ryan Hart, and I am a Senior in Civil Engineering at Colorado School of Mines. I am from Littleton, Colorado and I am blessed to live in such a great state. In my free time I enjoy getting to hang outside and go up into the mountains. I really enjoy anything sports related, whether that is watching or playing. Mines has been a great experience for me and has helped me see how well it can prepare me for future employment in my field. I want to pursue a career in either Structural or Project Management, but I have found that there are so many things that I can do with my degree that I am still unsure exactly what my path forward will look like. I want to be able to make an impact with the knowledge I have received from School of Mines and find something I am deeply passionate about in the upcoming years. Being a part of this design capstone team has been beneficial and has allowed me to have more experience with finding the best solution with the same team. Being able to utilize a team full of different minded individuals over a longer project period have been a great experience.
Thomas Mitchell
My name is Thomas Mitchell, and I am in my last semester studying Mechanical Engineering at Colorado School of Mines. I am from Colorado Springs, Colorado and decided to go to Mines due to the challenging curriculum and the proximity to the mountains. I love doing anything outdoors and I am always looking forward to the next great adventure. If I am not outside enjoying nature or doing homework, you can find me watching sports and enjoying time with my friends. While learning at Mines, I began participating in Air Force ROTC and found my passion for service and an amazing team to be a part of. I am to commission as 2nd Lt upon graduation and will eventually begin training to be a pilot in the United States Air Force. I believe my experiences in Senior design have made a significant impact on my professional and personal skills and will undoubtedly make me a more prepared and ready servant leader for my country.
Sophia Modar
I am Sophia Modar, a senior in Mechanical Engineering at Colorado School of Mines. I am originally from Sacramento, California but it looks like I will be making Colorado my home for the foreseeable future. I am excited to be joining the Aerospace industry after I have graduated. Outside of school I enjoy skiing, tubing down the creek, and hanging out at one of Golden’s breweries. I play on the Mines Women’s Rugby Team in times when tackling people is social acceptable. I thoroughly enjoyed being a part of this Senior Design project because of the new skills I learned, being able to help the community I live in, and having a fun group of people around me.
Hunter Szuszczewicz
My name is Hunter Szuszczewicz, and I am a senior majoring in mechanical engineering and minoring in chemistry. I was raised in Colorado Springs, Colorado, and consider myself lucky to have been able to live in this state for so long. In my free time, I enjoy tinkering, outdoor recreation, and online gaming. My professional aspirations are to move into the field of nuclear energy, where I hope to be part of developing the groundwork for a cleaner and more prosperous future. Being a part of this group has been a good exercise in working in a group environment, which will undoubtedly be foundational to my future success.