September 4 - Ohio, USA-headquartered PSC Crane & Rigging has supplied a Hydra-Slide HT500 heavy track hydraulic skidding system and four newly acquired JS250 jacking load shoes to setup and assemble a boring machine at the Dugway Storage Tunnel in Clevel

The boring machine, which had a diameter of 27 ft (8.2 m), is part of a USD150 million project to reduce the level of environmental pollution in Lake Erie by collecting, storing and treating waste and rain waters.

PSC was responsible for transporting the over-dimensional tunnel boring machine components to an installation shaft, lowering six of 12 pieces - the largest of which weighed approximately 500 tons (453.6 tonnes) - and assist with the assembly 200 ft (61 m) beneath the surface.

The other six, smaller components were lowered using a crawler crane.

PSC loaded the components onto 20 axle lines of self-propelled modular transporters (SPMT) before moving them 0.8 km to the shaft. There, a 700-ton (635-tonne) capacity hydraulic gantry served as a lift tower in conjunction with an 800-tonne capacity Enerpac strand jack atop 80 ft (24.3 m) girder beams spanning the 200 ft (61 m) deep shaft, which had a diameter of 50 ft (15.2 m).

Randy Sever, executive vice president at PSC, explained: "The main shield or protective structure of the boring machine was the heaviest and 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 was combined with Hydra-Slide's 250-ton (227-tonne) capacity JS250 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 tons (907 tonnes). The skidding system and load shoes were operated with a Hydra-Pac synchronous diesel pump, also supplied by Hydra-Slide.

Sever said: "The advantages of using the "Up 'N Go" skid shoes were two-fold. First, we were able to increase the capacity of the HT500 to 1,000 tons [the total assembled weight of the boring machine was 608 tonnes] and, second, they offered us finite final placement and alignment capabilities."

The project is overseen by a joint venture formed by Lane Construction Corporation's subsidiary S.A. Healy, and Lane Construction's parent company, Salini Impregilo. The project is scheduled for completion in the first or second quarter of 2018.