Work

A wooden walkway spans between rocky cliffs above a narrow creek, with green trees growing amidst the rugged terrain.

Tonto Natural Bridge State Park

Immersed in an Iconic Natural Landmark

Tonto Natural Bridge, believed to be the largest travertine natural bridge in the world, is one of Arizona’s most striking geological formations. Standing 183 feet high and spanning a 400-foot-long tunnel that measures 150 feet at its widest point, this natural wonder was shaped over thousands of years by Pine Creek’s erosion of travertine deposits.

Our project aimed to enhance visitors’ experience with the creation of a new steel pedestrian bridge and viewing platform. Designed to blend seamlessly with the native landscape and geology, the bridge’s materiality and texture were carefully selected to complement its surroundings. The entrance to the bridge climbs against the canyon wall, reaching a natural cleft in the rock where the bridge spans over Pine Creek.

Given the remote location at the bottom of a canyon, the bridge structure was designed as a modular system, allowing for off-site fabrication and helicopter delivery of bridge sections. Anchored to the existing bedrock, the bridge and viewing platform provide immersive and safe access to this unique piece of Arizona’s natural heritage.

A view from inside a cave looking out towards a rocky landscape with trees and a small footbridge in the distance under a partly cloudy sky.
Topographic site plan featuring contour lines, labeled paths, and natural features. Indicated locations include “Outlook,” “Clearing,” “Waterbody,” among others. Scale and north direction shown at the bottom.
Rock formation with a large cave opening and a wooden walkway bridge crossing over a stream surrounded by dense greenery.
A person stands on a bridge over a rocky stream surrounded by dense greenery and a large rock formation.
A wooden walkway leads to the large, rocky entrance of a cave. Surrounding vegetation includes lush green trees and shrubs with rocky terrain on the hillside.
A cross-section illustration of a canyon showcasing a bridge over a deep chasm with trees on the cliffs and a waterfall cascading from the top into the canyon.
Two rusted metal bridges span between rocky cliffs in a forested area with lush green foliage.
People walk along a metal bridge path leading to a large cave entrance surrounded by rocky cliffs and greenery.
A child walks toward the camera while an adult follows on a footbridge surrounded by trees and rocky terrain. Another person is visible on a parallel footbridge in the distance.
A group of people stand and sit on a wooden deck, observing the large rock formations inside a cave with greenery around.
Visitors stand on a viewing platform, looking at the natural landscape and rock formations in a canyon. The scene includes trees, rocks, and a cloudy sky.
Visitors explore a scenic nature trail with wooden platforms and stairs amidst rocky terrain and lush greenery.
Topographic site plan of a natural area showing entry stairs, foot bridge, walking platform, walking trail, Pine Creek, and waterline. The plan highlights the Natural Bridge South opening.
A wooden bridge spans a narrow river within a deep, forested valley surrounded by steep, rocky hills.

Project Information

Location

Pine, Arizona

Awards and Recognition

AIA Arizona, Honor Award

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