Directional drilling is playing a key role in the upgrade of a section of Historic Route 66 in San Bernardino County, Calif.
PTM Engineering Services Inc. of Riverside, Calif., will update existing obsolete traffic signals at three intersections as part of the work in the Caltrans project.
Caltrans requires the installation of conduit under its roadways with directional boring, only allowing a contractor to trench if boring wonâ€™t work for some reason. PTM subcontracted the directional drilling to Longâ€™s Directional Boring.
â€śWe have them come in and do just the drilling,â€ť said Peter Kobus, superintendent for PTM Engineering. â€śWe assemble the pipe and pull it in.â€ť Longâ€™s started boring conduit on July 22. There are actually a total of 20 boring shots to be made among the three locations, Kobus said. Each location receives three street crossings, plus the conduit that goes to the advanced vehicle detectors (loops) that are approximately 200 to 250 linear feet from the intersection. Average intersections get seven directional drill shots: three crossings and four advanced loops for each direction.
Boring for the intersection varies by the width of the street and the amount of working space that is available, which can be challenging.
â€śAt the location at Acacia and Route 66 we failed the first attempt to cross Acacia on the South side because of inadequate working space,â€ť Kobus recalled. â€śWe had to relocate the boring machine, which added another 10 feet to the bore shot.â€ť
The Ditch Witch JT2020 Mach 1 directional drill that Longâ€™s Directional Boring is using on the Historic Route 66 project packs 20,000 pounds of pulling power and is engineered with a one-step anchoring system for quick setup. Its groundbreaking pipeloader allows column selection from the operatorâ€™s station.
According to Ditch Witch, the JT2020 Mach 1 has the highest ratio of power to size in its class, which allows it to install larger product in a wider variety of soil types, even in tight areas.
The 85-horsepower Cummins B3.3TAA engine produces only 103 dbA of noise due to Tier 3 update, for increased operator comfort and reduced environmental impact in urban areas. The new Tier 3 design also allows incorporation of an advanced cooling system with a variable-speed fan; this provides additional cooling automatically, for better all-day operation, especially in warmer climates.
On average, an intersection street crossing will be between 60 and 80 feet, but some major intersections can range from 120 to 140 feet, Kobus added. The distance for advanced loops (vehicle detection) for intersections depends on the speed limit of the street. The higher the limit, the farther away they are from the crosswalk of the intersection. Generally this will range from 180 feet to 350 feet, depending on the speed limit.
Kobus said the project is scheduled for completion in 60 to 90 days and was on time when he talked to CB&E in late July.
Note: This article appeared in the September 2009 issue of California Builder & Engineer, an ACP magazine.