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PSE&G Orange Height Substation

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The project consisted of the replacement of existing Coal Bay Walls for PSE&G Substation. The walls are bound by NJ Transit Railroad that needs to be protected. Underpinning worked closely with the client and geotechnical engineer to complete a load testing program and install drilled micropiles.

The project consisted of the replacement of existing Coal Bay Walls for PSE&G Substation. The walls are bound by NJ Transit Railroad that needs to be protected. Underpinning worked closely with the client and geotechnical engineer to complete a load testing program and install drilled micropiles.

There were 168 each 9-5/8-in drilled micropiles installed across 12 Coal Bays adjacent to NJ Transit Railroad using air with a Casagrande C5 micropile rig. Micropiles were installed in 5-foot cased sections to an average depth of 30 feet with an additional minimum rock socket of 20 feet. Out of the 168 micropiles, 96 each were installed plumb and 72 each were installed at a 30 degree batter. Piles were designed to optimize loads transferred at each coal bay.

The confined space within the coal bays posed a significant challenge, especially for the battered piles, with the C5 micropile rig barely fitting in the tight quarters. The rig's set up in the area also blocked an access lane outside. Careful coordination with the General Contractor to schedule their adjacent work strategically was necessary.

Did you know?
The plumb micropiles were designed with a 119-kip tension capacity and the battered micropiles 166-kip compression capacity. Test piles were installed prior to production work commencing for a total of four test piles (one plumb and three battered micropiles). Careful design and construction of the piles and load test frames was vital to accurately measure design loads especially at the battered locations.