Photo by Ali Harper Photography
HIDDEN IN PLAIN SIGHT A Gabion Bridge
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In order to construct the Selborne Lane gabion bridge, its path was cleared with edging placed around the border and a weed mat positioned to keep weeds out. Builders then began stacking the wire boxes filled with rocks. Rock placement is as important as the box material, with the flat side facing outward and corners positioned inside. Cement blocks were used for the middle portion, and there are vertical diaphragms used to keep the bridge intact and hinder internal movement of materials within the boxes. This ensures plants and water can flow in between the materials and help us build with nature not against it. “Serenbe was designed to be a part of nature, and the best part of the gabion bridge is that it accomplishes that by becoming one with nature over time,” says Steve. “Silt and vegetation collect within the rocks to form a naturally imperishable structure, which strengthens the environment.” Take a walk along one of the two gabion bridges.We just built a second one to connect Grange to the Mado neighborhood across another natural ravine and stream crossing.
Photo by Ali Harper Photography
f you’re driving or taking a stroll on Serenbe Lane in Grange past the Textile Lofts, you may have looked out into the woods and noticed the earth seems to just drop off past the road. It looks like a bridge, and yet it also looks like the road is just an extension of the land. This is because it’s not your average bridge, but a bridge with a Serenbe twist – it’s called a gabion bridge and it’s inspired by engineers in South America. The roads in Serenbe are curved to follow the natural ridge lines of the land. When it came time to continue Serenbe Lane into Grange it needed a curve – difficult to do in our straight, pipe-filled bridge world. A gabion, however, infuses recycled materials – rocks, concrete, etc. – inside multiple stacked coated, galvanized or stainless-steel cages, cylinders or boxes, which nurture the shape of the bridge structure and ensure its lifespan. “Building a traditional bridge through this area would have required razing nearly 70 feet of land and trees from each side,” says Serenbe CEO Steve Nygren. “We found the gabion model to be a better and more environmentally-friendly way to handle stream crossings.”
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FALL/WINTER 2018