At historic Penn’s Landing, developers faced two potential hazards when constructing the 24-story Hyatt Regency and its adjoining nine-story parking garage along the waterfront. Would they encounter existing soft hydraulic fill? Or remnants of old piers that predated construction of the adjacent Boat Basin and Maritime Museum? Schnabel was engaged to help address these risks.

At the site of what is now known as the Hilton Philadelphia, we conducted a comprehensive subsurface investigation and provided geotechnical design and follow through construction monitoring. We concluded that deep foundations were needed to support these structures due to the very high column loading and subsurface conditions. Based on our analysis and past experience with nearby projects, driven piles were expected to be the most cost effective foundation system. However, working closely with the developer and local piling contractors, an alternative foundation system using auger cast piles was selected.

A test pile program was developed to evaluate whether the auger system would be able to penetrate the random fill to the depth necessary to obtain the required capacity of 120 tons. Based on the test program, including a load test to three times the design capacity, 16-inch diameter auger cast piles were adopted, resulting in significant cost savings. We provided full-time pile installation observation services for the nearly 550 production auger cast piles.

Photo: Courtesy of Hilton