Moving a fully assembled bridge across a remote Alaskan canyon demanded more than hydraulic power. It required precision, synchronization, and control at every stage of the launch.

The Juneau Creek Bridge, located on Alaska's Kenai Peninsula, spans 928 ft across a steep canyon and stands 285 ft above the creek below. Expected to become the longest fully assembled bridge launched into position in the United States, the project presented a unique engineering challenge for the construction team and project partners.

Working alongside KWH Constructors Ltd. and Traylor Bros., Inc., Enerpac designed and supplied a custom hydraulic bridge-launch system to help move approximately six million pounds of permanent steel safely into place.

Constructing a bridge in a remote Alaskan location brings challenges of its own. Launching one of the longest bridges ever assembled before installation adds another level of complexity.

With no practical access beneath the canyon, the bridge could not be erected using conventional methods. Instead, the entire structure had to be assembled on one side of the canyon before being pushed incrementally across the gap into its final position.

The project team faced several critical requirements:

• Move a 928-ft bridge weighing approximately six million pounds
• Maintain alignment throughout the launch process
• Monitor how the structure responded as loads changed
• Provide operators with real-time feedback
• Stop or adjust movement quickly if conditions varied from plan

Perhaps most importantly, the bridge needed to remain within extremely tight alignment tolerances as it advanced hundreds of feet above the canyon floor.

To meet these demands, Enerpac developed a custom synchronized hydraulic launch system designed specifically for the project. At the heart of the solution were four custom hydraulic launch cylinders, each featuring a 10-ft stroke. Working alongside integrated clamping and leveling cylinders, the system provided the coordinated movement required to advance the bridge safely and accurately.

The launch system continuously monitored pressure, position, and movement throughout each stage of the operation. This real-time feedback enabled operators to track bridge behavior, monitor hydraulic loads, and maintain alignment as the structure progressed across the canyon.

Enerpac engineers from North America and Madrid provided engineering support throughout the project, working closely with KWH and Traylor Bros. during planning, commissioning, and launch operations. During the initial push cycles, actual bridge loads and structural response were evaluated, allowing the team to fine-tune system performance and support smooth, controlled movement.

The outcome was more than a powerful hydraulic system. It was a coordinated platform combining launching, leveling, clamping, monitoring, and control into a single engineered solution.

Over approximately seven to eight days, the bridge advanced across the canyon in carefully controlled increments. Through synchronized hydraulic movement and continuous monitoring, the project team maintained alignment within a reported tolerance of approximately one inch while moving one of the largest bridge structures ever launched in the United States.

Project Highlights

• 928-ft bridge length

• 285 ft above Juneau Creek

• Approximately 7 mil.lbs of permanent steel

• Four synchronized hydraulic launch cylinders

• 10-ft cylinder stroke

• Real-time pressure, position, and movement monitoring

• Approximately 1-inch alignment tolerance

• Engineering support from North America and Madrid

Beyond helping deliver a landmark infrastructure project that improves connectivity between Anchorage and the Kenai Peninsula, the custom launch system demonstrates the value of combining hydraulic technology with engineering expertise and close project collaboration.

Designed with future bridge-launch applications in mind, the system also provides a reusable platform for tackling large-scale infrastructure projects where access constraints, structural loads, and precision requirements demand a highly coordinated solution.

Planning a complex bridge launch? Talk to our engineers about your next heavy-lifting or bridge-launching challenge.