The length of the ramp and height of the tower became key factors in keeping the project on budget and in meeting objectives to minimize the project ’ s impact on the forest as much as possible , Sydow said .
“ We wanted a tower that went vertically to the appropriate views , but also we didn ’ t want to disturb more trees than necessary or other features in that area , including an older pavilion that ’ s been there for years and years , and stone masonry retaining walls that we wanted to avoid impacting . The whole layout of the ramp and tower also had to function well with the parking area and with nearby trails for hiking and biking . We needed to be sure it all worked together in a safe way .”
To determine the optimal tower height and ramp length given budgetary and environmental factors , Ayres conducted a study using a camera-equipped drone to capture views at various heights ( 35 feet , 45 feet , 55 feet , and 65 feet ). The team concluded the new tower could be built to a 55-foot height – down from the 75- foot height of its predecessor – while still offering visitors the expected spectacular views and providing accessibility via an 850-foot approach ramp . Upheld by 20 support towers increasing in height along the approach to the main tower , the ramp would maintain a grade of no more than 8.3 percent , per ADA requirements .
Also guiding the planning for the new Eagle Tower was stakeholders ’ commitment to nature-based design .
“ That was always a desire of everybody involved ,” Sydow said . “ We didn ’ t want to build something out of steel or concrete that didn ’ t fit the natural environment of that area . So that meant looking at alternatives that are not only from sustainable resources , like timber , but also would be appropriately treated to last there for a long , long time .”
The Ayres structural engineering team worked in consultation with the worldrenowned federal Forest Products Laboratory , a part of the U . S . Forest Service , to select materials for the new tower . “ They have a laboratory here in Madison , Wisconsin , where they do research into various uses of timber products ,” Sydow said . “ We met with their experts to talk through what would be the desirable types of materials to use and how we would use best practices to make sure that the tower not only matches well with the natural environment but performs well long into the future .”
Taking It to the Finish
In 2018 , Ayres was hired again to provide final design , construction bid documents , and construction administration services for the new Eagle Tower . Ultimately , the work of Ayres ’ landscape architecture , geospatial , structural engineering , municipal engineering , architecture , survey , and environmental services groups contributed to the project ’ s success .
The new Eagle Tower , which in addition to its iconic ramp includes 95 steps leading to its two observation decks , was opened to the public in spring 2021 . The $ 3.7 million project was a partnership between local and state legislators , the DNR , and the Friends of Peninsula State Park , which donated $ 750,000 to the effort .
A “ Fresh ” Approach to Accessibility
Those involved in the new Eagle Tower project say the use of an accessible approach ramp through the surrounding forest canopy is a unique solution not found
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34 | TRENDS Ingenuity , Integrity , and Intelligence .