Treetop Trail at the Minnesota Zoo

THE PROJECT

Project Highlights

Public-private partnership project led by the Minnesota Zoo Foundation
1.25-mile-long, 32 ft high elevated walkway, the longest pedestrian loop in the world
Adaptive reuse of a former aging monorail track, closed in 2013

Treetop Trail at the Minnesota Zoo, the world’s longest elevated pedestrian loop, reimagines a decommissioned monorail track into a 1.25-mile accessible walkway. Rising up to 32 feet above ground, the trail offers immersive views of animals and nature, enhancing the visitor experience while exemplifying sustainable design through material selection and intelligent strengthening methods. Constructed amid a global pandemic, while the zoo remained fully operational, the project overcame unique site constraints including building over wetlands, existing structures, and guest areas.

OUR IMPACT

ADAPTIVE REUSE

of old monorail into elevated walkway

UNINTERRUPTED

zoo schedule during construction

VIBRANT PUBLIC ASSET

for the community

Service Provided

Structural Engineer of Record

OUR SOLUTIONS

MBJ served as the Structural Engineer of Record, along with design partner Buro Happold, navigating complex structural challenges including structural integrity, site constraints, thermal expansion, and environmental impact. A lightweight steel reinforcement structure was selected for its compatibility with the existing weathering steel, ability to modularize construction, and the lowest embodied carbon of systems considered. A key complexity of the 1.25-mile steel loop was its continuous nature with no expansion joints, requiring advanced modeling to predict thermal movements and locked-in forces. Structural solutions using existing slide bearings, keeper plates, and soil spring analysis were utilized to maintain the walkway’s integrity. With ADA-compliant access points and seating throughout, the trail offers an inclusive experience for all visitors. Our collaborative approach with the zoo, contractor, architects, and engineers ensured the project remained within budget and achieved all functional and aesthetic goals. The trail now provides a unique perspective of the zoo while delivering lasting value to the community.

Project Details

Location:

Apple Valley, MN

Completed:

2023

Construction Cost:

$37,000,000

Owner:

Minnesota Zoo Foundation

Architect:

Snow Kreilich Architects

Contractor:

PCL Construction

Structural Partner:

Buro Happold