BRIDGE THE GAP
2nd Year Design-Build
(Video: Bridge at Capacity)
Our group was tasked with the assignment of building a footbridge, while making thrifty and economical material choices, that spans exactly 12 feet and supports a high capacity with the smallest expenditures possible.
The group decided to recycle nearly all of our materials—metal fencing, fence clips, frames and posts—from the Penn State salvage yard. The wood and brackets were leftovers from one of the groupmate’s home deck project.
I had a hand in nearly every stage of design and construction of the bridge, including: choosing fencing as the material for the footpath, designing the connection from the steel frames for the fences to the pipes—which held it to the truss—cutting the fencing panels and frames to size and welding them together, and connecting the planks of the truss together by brackets.
SECTION A
Ninety-degree notches were cut on both ends of each recycled fence post so that they could be set on the top face of the upper truss chord and rest between both sides of the wooden chords.
Then, fence clips (bottom left) were pulled over these posts and had the rectangular steel frames for the walkway panels fit in the gap, before the whole assembly was secured by bolts. Metal fencing was woven around and inside of these frames and welded shut at the ends.
The entire walkway assembly could be folded into the length of one panel and carried elsewhere, whereas the truss system was more permanent.
The trusses were assembled from 2 x 4's gathered from a group-mate's previous project and from wooden pallets at the snowy salvage yard (bottom right) on Penn State's campus for no cost. We connected all the cut-to-fit wooden members with mending (top left and right) plates from the same group mate's extracurricular deck project.
We got the fencing material from the same trip to the salvage yard, where we discovered and took a 30-foot spool of fencing wire. We cut strips from spool to the exact width of the walkway panels before trimming them in the other direction (bottom left) with a grinder.
We cut to size individual sides for each frame, 16 pieces in total, from a few strips of salvaged steel. We retrofitted these frame pieces so that they could be woven precisely through the fencing panels.
