What is a Moveable Bridge?!?

I figure it’s about time I talk about one of the key tasks for me this semester, the 236 Moveable Bridge project. While you may suspect this is simply a version of the first-year truss project we all know and love, the 236 bridge project is far, far better.

This is a 12-week long 45% project, representing the culmination of your design knowledge and ability as a 2nd year mechanical engineer. As Mechanical engineering fundamentally is about working in team with the purpose of designing products for practical use, skills in team-work and project management you learn during this assignment are far more important in your growth to become a mechanical engineer than any theoretical knowledge you will gain in lectures.

The project starts on the first day of semester. In the very first tutorial in the first week, you select a team of three other students to work together. How well you work as a team basically decides your project outcome, so make sure you get on well with your team members. I’m extremely happy with my team members. They are all interesting, intelligent people with a hilarious sense of humour and a passion for mechanical engineering.

The design brief changes from year to year, but the core requirements remain the same. The brief calls for a relatively short bridge (this year, the required length is 5m) to be built over a small body of water. The bridge must somehow be able to raise to let water traffic to pass underneath. As a team, you must design the structural and mechanical aspects, complete all necessary stress, strain and force calculations to ensure the bridge will not fall down, and then build a physical scale model to show to the stakeholders (the tutors and lecturers) during an interview. This relies on theoretical knowledge from first semester, and content being taught in courses this semester.

After research and conceptual design, my team selected a design based of the Wynyard Crossing. This is a single leaf cable stayed bascule bridge. To help us with the detailed design process, we got in contact with the company who designed and maintains the Wynyard Crossing, and they agreed to show us the detailed drawings and then take us on a tour of the bridge. This involved taking us underneath the deck and into the mechanism housing, where we got to see the motors and transmission system that raises the bridge. The complexity of the design was amazing. The hundreds of people who cross the bridge everyday have no idea the engineering magic that goes on behind the scenes to operate the bridge.

The Wynyard Crossing, an example of a Moveable Bridge.

At this point in the project, we must now create CAD files of our design and begin construction of the scale model and the accompanying report.

As someone who did not enjoy the first semester design course (MECHENG 235) or ENGGEN 115, I was very wary going into this project, but it was been thoroughly enjoyable and engaging. We are creating something entirely new. From a few brainstorming sessions and moments of inspiration, we came up with the idea and have transformed this into the technical drawings, specifications and a scale model of a functioning bridge (hopefully). This is what the mechanical specialisation is all about. Taking ideas and using science to make them a reality and create a safe, functioning product for the final customer to use.

Until next time