OasisLMS

Abstract: A chemical facility was constructed in the early 1900’ s along the Delaware River in Philadelphia to allow for movement of chemical products through the waterway. The facility was constructed with a roughly 152 meter (500 foot) long timber relieving platform, including timber decking and timber piles extending into marine soils and backfill atop the platform. The facility includes two containment slabs on grade that house a majority of the piping and mechanical equipment, multiple storage structures, and 14 columns that support the overhead piping across the length of the platform. The columns are supported on spread footings bearing on the fill material that was placed above the timber decking. A dive inspection of the platform was performed in 2022 and concluded that the timber decking and piles had notable deterioration. It was also noted the relieving platform, and site in general, required rehabilitation to support further operation of the plant. Rehabilitation activities included replacement of the platform decking and construction of a new structure. The facility needed to be kept operational during construction to support plant production, therefore bypass systems and temporary underpinning was required to keep pipes and instrumentation in operation. Given an allowable deformation of 6 mm (1/4 inch) for overhead utilities and site constraints such as an reduced capacity of the existing timber platform, soft marine soils, and restricted working room, an unconventional underpinning method was required. Opposed to supporting the structures from the bottom as seen in conventional techniques, the structures were picked up from the top using a series of steel members and jacks, and suspended in air during construction. This paper will focus on the design and successful implementation of the innovative techniques. Implementation of these techniques provides more opportunities to perform underpinning at locations where typical underpinning is impractical.


Keywords: underpinning, deep foundations, marine, innovative

Mike Senior; Mrs. KIRSTEN Grant

Annual Conference Proceedings