In 2012, the Honolulu Rail Transit Project began the construction of a 20-mile elevated rail line. The goal of the rail system is to alleviate significant traffic issues affecting Hawaii’s most congested city. Kiewit, a construction company headquartered in Omaha, Nebraska, was tasked with the design and construction of the elevated rail guideway.
Once the steel box girders are launched and aligned on the pier brackets, custom Enerpac 150-ton locknut cylinders are mechanically locked, ensuring the system maintains its precise location.
PRECAST SEGMENTS
In order to accelerate the construction timeline, while maintaining a high level of quality, Kiewit selected a segmental precast span-by-span construction technique to complete the project, which featured a twin underslung girder system designed by Kiewit. The first 10 miles of guideway consists of 5,200 guideway precast segments, which are casted at an off-site casting yard, then delivered onsite for installation. Each segment weighs up to 50 tons, and requires a positioning system with a significant amount of force and precision to ensure accurate installation.
In designing the twin underslung girder system, Kiewit turned to Enerpac to engineer and deliver the hydraulic control package. Each of the twin underslung girder systems are supported by pier brackets on each end, which are transversally positioned and aligned with custom Enerpac TR-Series hydraulic tie rod cylinders. The double-acting tie rod cylinders allow for a high amount of precision, combined with a durable seal design for long cycle life.
“We specified our hydraulic tie rod cylinders to provide accurate positioning for each bracket, and to ensure reliable performance of the girder systems,” says Tyson Wiegel, integrated solutions specialist, Enerpac.
PRECISE PLACEMENT
Once the steel box girders are launched and aligned on the pier brackets, custom Enerpac 150-ton locknut cylinders are mechanically locked, ensuring the system maintains its precise location. The guideway segments are then picked via crane and placed onto a set of segment carts where they are supported by 50-ton custom Enerpac CLL-Series hydraulic locknut cylinders.
“Our safety lock nut cylinders are available in capacities up to 1,000 tons, which makes them ideal to support the guideway segments of various weights,” says Wiegel. “They also provide superior corrosion resistance to withstand a variety of environmental conditions.”
Utilizing the segment carts, the segments are precisely aligned and maneuvered into position. The segments can then be epoxied and post-tensioned together, completing the span.
“Utilizing span-by-span advancement enables multiple phases of the project to occur simultaneously, thus helping to reduce the overall project timeline while ensuring each span is installed correctly,” adds Wiegel. ■
For More Information: For more information on Kiewit, visit www.kiewit.com. For more information on Enerpac, visit www.enerpac.com.
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Modern Contractor Solutions – February 2016
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Span-by-Span Advancement
