[Job Story] Two Liebherr Cranes Building Alaska’s Longest Single-Span Bridge

Two Liebherr crawler cranes are currently deployed in the construction of the Juneau Creek Bridge: the longest, single-spanned bridge in Alaska. With a span of 290 metres, the bridge has the purpose to significantly increasing the traffic capacity on the Sterling Highway, a key corridor connecting Anchorage to the Kenai Peninsula, while also improving road safety. Traylor Bros, a U.S.-based heavy civil contractor, is leading the project and has chosen to employ two Liebherr LR 1300.1 SX crawler cranes for the most critical lifting operations on site.

The project is a launched bridge, likely the longest of its kind in North America. This construction method allows massive steel sections to be positioned with high precision, without the need for extensive scaffolding across the canyon. The structure relies entirely on solid steel girders, selected for their ability to span long distances while offering high load-bearing capacity with minimal material weight. But this is no ordinary build: the girders must be aligned with millimetre accuracy to achieve the structural stability demanded by such a span. That level of precision is one of the key reasons the contractor chose Liebherr tower cranes, trusted for their handling accuracy and reliability on complex infrastructure projects.

The steel girders are assembled on one side of the canyon and then gradually pushed across the deep Juneau Creek Canyon to Cooper Landing using hydraulic presses.

 ‘The most challenging lift for us was the first girders of the bridge. They were very heavy, and I had to rely on a lot of ground people because the wind was coming in. We could see up to 40 miles per hour winds. So I am very happy that we therefore have two Liebherr crawler cranes, one on each side of the project’

Explained Travis Ludlow, crane driver of one of the LR 1300.1 SX at Traylor Bros, Inc.

He also highlighted the performance of the cranes’ Gradient Travel Aid, a crucial feature given the steep and uneven terrain of the jobsite. The system enhances safety by continuously monitoring the crane’s centre of gravity and alerting the operator before the machine reaches a critical tilt. While moving across sloped ground, the operator receives real-time data on both actual and permissible gradients, as well as the current centre of gravity. If needed, the boom angle can be adjusted dynamically to keep the crane within safe operating limits.

The scale of the project also lies in the demanding conditions under which it is being built. The Juneau Creek Bridge must withstand Alaska’s harsh climate, along with the ever-present risk of seismic activity. All these factors were carefully integrated into the structural design to ensure long-term resilience. Adding to the complexity, the remote location and protected natural surroundings required precise environmental planning to minimise ecological impact. Steep terrain and narrow access roads made the logistics of transporting and placing massive bridge components particularly challenging. To overcome this, Traylor Bros relied on Liebherr’s Crane Planner 2.0 software to simulate every lift in advance. The 3D tool allowed the team to anticipate constraints and refine each operation, helping ensure that the project stays safe, efficient, and on schedule.

As the LR 1300 crawler crane marks its 18th year of service, the two latest LR 1300.1 SX units are taking part in a landmark assignment, building one of North America’s most ambitious bridge projects.

[Job Story] Two Liebherr Cranes Building Alaska’s Longest Single-Span Bridge published on The HeavyQuip Magazine.