Boring unit lowered into the Dugway Storage Tunnel
To set up and assemble a 27-foot diameter boring machine at the Dugway Storage Tunnel in Cleveland, Ohio, PSC Crane & Rigging supplied a Hydra-Slide HT500 heavy-track hydraulic skidding system and four newly acquired JS250 jacking load shoes.
PSC role on the project was to load the over dimensional, overweight tunnel boring machine components, transport them to an installation shaft, lower six of 12 pieces (the largest weighing nearly 500 tons), and assist with assembly 200 feet beneath the surface. The other six, smaller parts were lowered by crawler crane with the piecemeal descent taking place in sequence. PSC was then slid the reassembled boring machine approx. 300 ft.
Before moving the components a half mile into the shaft, PSC loaded the components onto 20 lines of self-propelled modular transporter (SPMT). SA 700-ton capacity hydraulic gantry served as a lift tower in conjunction with an 800 metric-to- capacity Enerpac strand jack atop 80-foot girder beams spanning the 50-foot diameter, 200-foot deep shaft.
Randy Sever, executive vice president at PSC, said: “The main shield or protective structure of the boring machine was the heaviest and was lowered onto the HT500 first. Then we lowered the cutter head that was mounted onto the main shield. The other 10 parts of varying sizes and weight we lowered sequentially by the strand jack and crawler crane.”
Once on the shaft floor below, the HT500, which can be used to move almost all types of heavy loads, combined with Hydra-Slide’s 250-ton capacity JS250 “Up ’N Go” load shoes that are engineered as an add-on to the standard HT500 track. The shoes can be connected hydraulically with any number of other units, increasing the system capacity to multiples of 1,000 ton while maintaining equal load support and weight distribution between all points. The skidding system and load shoes were operated with a Hydra-Pac synchronous diesel pump, also supplied by Hydra-Slide.
“The advantages of using the “Up ’N Go” skid shoes were two-fold,” Sever said. “First, we were able to increase the capacity of the HT500 to 1,000 tons [the total assembled weight of the boring machine was 671 tons], and, second, they offered us finite final placement and alignment capabilities. The HT500 and “Up ’N Go” load shoes added efficiency in setup, skidding, lifting and lowering operations.”
The equipment was integral to the heavy lift and transport portion of the $150-plus project, which is part of a broader plan for the collection, storage, and treatment of waste and rain waters. The project’s objective is to reduce the level of environmental pollution in Lake Erie.
Overseen by a joint venture formed by Lane Construction Corporation’s subsidiary, S.A. Healy, and Lane’s parent, Salini Impregilo, the project included a contract to build the Dugway Storage Tunnel. The boring machine is now in full operation with tunneling well underway. The project is scheduled for completion in Q1 or Q2 2018.
