API Summer 2021

While the catenary bridges are not wheelchair or stroller accessible like the ADA bridges, the open access de- sign still offers visitors of differing ages and mobilities the opportunity to dial up the challenge. Utilizing a tight team of riggers and carpenters, Synergo began the build in June 2020 after a year of R&D in part- nership with the zoo and design and management firm Greenway Partners. The project took 7 months to complete. To minimize the environmental impact of the installation, the crew “stayed off of the ground as much as possible to avoid soil damage from root compac- tion,” says Marter. “Once the project was done, you couldn’t even tell the crew had been there.” The nine platforms utilize Synergo’s nor- mal design “reworked,” Marter explains, built so they’re not right up against the tree, as always, with the added ability to open and close like a camera lens to adapt to different tree sizes. The most labor-intensive part of the job was pull testing the brackets that connect the

bridges to the platforms. It took half a day to two days each depending on load requirements. “We had to do 32 of those tests,” says Marter. The elevated walkway blends in with forest as much as possible. The ascent ramp and launch deck are wood struc- tures with concrete foundations and surfaced with Dynaplank (a walkable tread surface that is non-slip and dura- ble). Posts and handrails are redwood, and metal panels are infilled between posts. Fabricated aluminum was used for the bridges and platforms, which have the same Dynaplank surface for walking, with railings made from cable and metal mesh panels. VINS Forest Canopy Walk (Weller & Michal Architects, Phoenix Experiential Designs) Vermont Institute of Natural Science, Quechee, Vt. When choosing a site for its Forest Can- opy Walk, the Vermont Institute of Nat- ural Science (VINS) had two main goals: get everyone into the trees at elevation, and minimize environmental impact.

“We looked at various sites when we were trying to place the walkway,” says lead builder Robbie Oates of Phoenix Experiential Design. “By utilizing the topography, we were able to eliminate a lot of the design challenges that come with building for ADA access.” The natural elevation variations of the land, which slopes toward the Ottau- quechee River, allowed the crew to fore- go structural elements with big foot- prints, like long access ramps or lifts, and build a canopy walk that remained largely level as the ground dropped away beneath it. The 815-foot wood-structured board- walk quickly puts visitors roughly 50 feet up in the trees. The walk’s 42-inch- high wood and mesh guardrails allow views of the woodland “for both young and old, regardless of one’s eye-level height,” notes VINS programs director Chris Collier. The landings, constructed of semi-solid wood plank decking, are connected by semi-transparent fiberglass grate walkways that shed rain and snow. “For anyone with a fear of heights, the ‘solid’ platforms of wooden decking provide a goal and relief as one moves along the fiberglass grating to the next platform,” says Collier. The design has several other ac- cess-conscious touches. Benches offer respite throughout the walk, which vis- itors take at their own speed. The entry approach path is constructed of small, crushed stones set in a plastic grate for wheelchair and carriage access. ^ The whole family can play on the VINS Forest Canopy Walk Spider Web, an open access net suspended 40 feet in the air.

The Treehouse, an emergent tower on the VINS Forest Canopy Walk, allows visitors to reach 100 feet above the forest floor without the need for ropes and harnesses.

Three feature nodes, while not ADA accessible, are open access. The first

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