The construction of the Juneau Creek Bridge with a span of 290 metres is the centrepiece of one of the largest infrastructure projects in Alaska, in the U.S. The bridge will significantly increase the traffic capacity on the Sterling Highway between Anchorage and the Kenai Peninsula and also improve safety.
Traylor Bros, Inc. relies on two Liebherr LR 1300.1 SX crawler cranes, which play a crucial lifting role during the assembly of the bridge sections. The steel girders of the bridge are assembled on one side of the canyon and then gradually pushed across the deep Juneau Creek Canyon to Cooper Landing using hydraulic presses, a technique known as bridge launch. Using this technology, the massive individual sections can be positioned precisely without the need for complex scaffolding across the chasm.
“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 have two Liebherr crawler cranes – one on each side of the project,” said Travis Ludlow, crane driver of one of the LR 1300.1 SX at Traylor Bros, Inc.
Ludlow says he is particularly pleased with the cranes’ Gradient Travel Aid for safely negotiating slopes, which is challenging given the project’s topographical conditions. The crane’s control system automatically calculates the centre of gravity and warns the operator before the crane leaves the safe area. While travelling, the operator receives real-time information on the permissible and actual gradient, as well as the crane’s overall centre of gravity. If necessary, the main boom angle can be adjusted to keep the machine within the safe area.
Decisive factors to choose a Liebherr crawler crane
Only solid steel girders are being used for the Juneau Creek Bridge. These allow for wide spans and a high load-bearing capacity with minimum material weight. The girders must be aligned with millimetre precision to achieve the necessary stability for the bridge. Traylor Bros, Inc. is carrying out this job with two crawler cranes, LR 1300.1 SX, so that the bridge can be built safely and efficiently across the canyon.
“There were several factors that went into the decision to choose the LR 1300.1 SX. The reliability of the crawler cranes is incredibly important for our project site. We have a small window before the weather kicks us out. Any malfunctions would cause massive schedule delays. The LR 1300.1 SX works when we need it. It has the versatility and the capacity to handle all the lifts we need to do,” said Tyler Becker, senior field engineer at Traylor Bros, Inc.
From planning software to lifting operation
The bridge has to withstand the extreme weather conditions in Alaska: strong snowfall, biting winds and great temperature swings. The seismic activity in the region was also considered in the technical calculations to ensure sufficient safety in the event of earthquakes. The remote location and the surrounding natural habitats required careful planning of the project to minimize ecological impact. Steep slopes and limited access roads make the positioning of large bridge components extremely difficult. Traylor Bros, Inc. planned the deployment of the two crawler cranes in advance and during the work, using Liebherr’s 3D software, Crane Planner 2.0. By simulating the lifts, the company is supported in accounting for all scenarios and finding solutions in advance so that the bridge project can be completed safely, efficiently and on time.
The crawler crane type LR 1300 just celebrated its 18th birthday. With the construction of the Juneau Creek Bridge, the two LR 1300.1 SX – the two newest models of the type – have found a spectacular anniversary project in breathtaking surroundings.