Suspension Dock
Geometry & Trigonometry
Explore the shape of the cables and the design of this dock.
Introduction
A post on social media: "Any of you guys have any experience with a suspension dock? I just completed mine. I think it should be ok but im no engineer, (just an idiot with an impact driver). I tapered the holes for the back post and concreted them in. Front post are sitting on concret cookies. Hoping that the front dont sink and back ones pull up. Holds my 240 pounds ok so far. 20' long 6' wide. Pond still a cple feet low. Hopefully it works out for the long haul but im not holding my breath lol"
Guiding Questions
- The dock hangs from cables between posts. What curve does each cable section follow under load?
- Model one span: fit a curve to its shape and find how steep the curve is at each support.
- How does adding a person at midspan change the sag? Predict how it changes, then check with your model.
- Compare designs: more posts with shorter spans versus fewer posts with longer spans. Which uses less cable?