NPCA Staff Report
It’s a sight drivers hate to see – orange barrels shutting down lanes of traffic on their rush-hour commutes. Such a scenario was exactly what Hawaii DOT could not tolerate when it became necessary to reconstruct 3.63 lane miles of Interstate H-1, the longest and busiest interstate in Hawaii, near Pearl Harbor just west of Honolulu. Sections of H-1 in this area, originally built on volcanic ash deposits between ancient lava flows, were heavily patched over many years, resulting in pavement surfaces that were unacceptably rough and deteriorated for the heavy, high-speed traffic in the area. A permanent upgrade was needed – without disrupting heavy traffic flow.
Photo courtesy of The Fort Miller Co., Inc.
Precast concrete paving slabs were chosen for a major highway project in Hawaii.
Permanent solution
In 2017, Hawaii DOT explored the concept of rebuilding this area with precast concrete paving slabs because of a growing interest in the method and its proven success as a way to repair heavily traveled roads without causing major disruption to the traveling public. By mid-January 2018, HDOT awarded a design-build contract to a team headed by Kiewit Infrastructure West Co., based in Kapolei, Hawaii. This method of contracting was selected because of the complexity of the underlying pavement structure, the difficulty in designing a new surface that could be built under heavy traffic conditions and because of the need for designing and building the entire project in just seven months.
Kiewit elected to use the Super-Slab System because of a proven track record of successfully installing similar projects during overnight work windows and a proven long term durability record.
Project Execution
Keys to the success of the project included Kiewit’s decision to place a temporary asphalt overlay on the existing pavement to minimize grade differences during slab installation, taking a Ground Penetrating Radar survey of the existing pavement prior to any excavation and use of laser-controlled grading equipment. Kiewit began installation during the first week of May 2018, and completed it the second week of August. Installation rates varied from approximately 20 to 30 slabs per 7.5 hour work window in most areas and as many as 57 slabs per extended weekend closures. Kiewit worked closely with all team members to accommodate design and schedule requirements throughout the project.
Photo courtesy of The Fort Miller Co., Inc.
By being able to quickly install the slabs during non-peak hours, traffic disruption was minimal.
Peter Smith, The Fort Miller Co., Inc.’s vice president of market development and product engineering, said the Super-Slab System provided many benefits for the project including shop drawing design, opening the slabs to traffic before they were fully grouted and the ability to meet all geometric requirements of the project including non-planar (warped) slabs. The final pavement design required slabs that varied in shape, thickness, reinforcing and planarity. Approximately 44% of the slabs on the project were non-planar as required to meet the final design surface model.
Successful precasting partnership
GPRM Prestress manufactured more than 1,300 paving slabs for the project in fewer than three months, and they received a lot of technical and engineering help from The Fort Miller Co., Inc. along the way.
Will Wong with GPRM Prestress said they were able to cast nearly 20 panels per day once they got up and running.
“The Fort Miller Co., Inc. ended up being a big help on this,” he noted. “We were both new to each other. We were able to integrate our business styles and get the project executed. Everyone felt really pleased afterwards.”
Wong said thanks to the success of this project, HDOT is considering precast paving slabs for other projects.
Certainly the goal of keeping drivers happy was achieved on this challenging project.
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