Washington’s Olympic National Park was designated a UNESCO World Heritage Site in 1981 as “an area of exceptional natural beauty.” Now, roughly 30 years later, Otak is helping people access this natural beauty.

Saybr Contractors hired the Otak/Prime Cut Construction team to design and build a pedestrian bridge on the Boulder Creek hiking trail. The 135-foot-long suspension bridge stretches over Crystal Creek and is designed to withstand pedestrians, heavy snowfall, and mule trains which are used for trail maintenance.

The unique design of the bridge is turning heads on the trail. Only one of the abutments has a tower for the main suspension cable. At the opposite abutment, the suspension cable is anchored to a rock cliff behind the abutment. This stroke of ingenuity reduced construction costs and provided more clearance between the rock cliff and the end of the bridge.

When dealing with such a prestigious location as a World Heritage Site, constructability weighs heavily on the designers’ minds. Only one side of the site was accessible by machine, so the steel tower and equipment necessary on the other end of the bridge had to be transferred across Crystal Creek using a system of cables and pulleys. The size of equipment and weights of materials necessary to build the tower and its foundations were restricted due to the limited access. The design utilized gabion walls to stabilize the trail on the east approach.

The care shown for the natural environment on this delicate project paid off, and the National Park Service is pleased with the results.